Tuesday brought a lot of sun and great heat from 35 to almost 38 degrees. At many stations there were top rankings for July in this respect, in Vaduz it was even the hottest July day so far. In the evening, strong thunderstorms spread from the west. There were above all exceptionally many lightnings and much wind – partly even in hurricane strength! Also on Wednesday thunderstorms are on the program!
Almost 100,000 lightning strikes across Switzerland
Last Tuesday afternoon, the first thunderstorms formed in western Switzerland (see ticker). Since then, staggered and partly powerful thunderstorms have moved across Switzerland. This has resulted in an exceptionally large number of lightning strikes during the past 36 hours. From Tuesday afternoon until Thursday morning, about 95,000 lightning discharges were registered throughout Switzerland. Thus, more lightning flashed over Switzerland in this short period of time than in the whole month of July last year (84,727 lightning flashes). The following table shows the number of lightnings by cantons. The measurements are based on the highly precise and worldwide leading lightning location system LINET from the company nowcast.
| Canton | Number of lightnings |
| AG | 5'181 |
| AI | 397 |
| AR | 1'012 |
| BE | 11'765 |
| BL | 913 |
| BS | 245 |
| FR | 4'092 |
| GE | 356 |
| GL | 753 |
| GR | 8'822 |
| JU | 2'750 |
| LU | 7'320 |
| NE | 385 |
| NW | 626 |
| OW | 1'282 |
| SG | 4'910 |
| SH | 836 |
| SO | 633 |
| SZ | 2'127 |
| TG | 8'471 |
| TI | 5'496 |
| UR | 1'219 |
| VD | 6'40 |
| VS | 3'802 |
| ZG | 1'743 |
| ZH | 13'527 |
In the current year, the lightning count for Switzerland currently stands at 236,810. For comparison, there were 354,484 lightning strikes over Switzerland in the entire 2022.
Area-wide precipitation
Since Tuesday, large amounts of rain have also accumulated in many regions throughout Switzerland. Locally, more than 80 liters of rain per square meter have fallen, for example at the measuring stations Flühli (LU) with 89 mm, Grono (GR) or Engelberg (OW) with 82 mm each. Since the rain fell in a staggered manner and thus with interruptions, there were no major problems with it. On the contrary: the rain was important for nature! The map below shows the rainfall amounts of the last 48 hours. The least rain has fallen from Geneva over the Jura arc to Basel.
Fig. 1: Rainfall amount for the last 48 hours until 05:00 Thursday morning; Source: MeteoNews AG / UBIMET
Since yesterday evening about 75,000 lightning bolts across Switzerland
Also today, Wednesday, repeated showers and thunderstorms passed through, the number of light nings has meanwhile increased to about 75'000 (yesterday just under 35'000 lightnings, today until 6 p.m. just over 40'000 lightnings, see the following two tables).
Fig. 1: Lightning number yesterday Tuesday; Source: MeteoNews, Ubimet
Fig. 2: Flash count today Wednesday until 18; Source: MeteoNews, Ubimet
Most lightning occurred in the cantons of Bern (10,559) and Zurich (9,563).
Up to over 60 liters of rain
With the thunderstorms, there were also large amounts of rain in the last 24 hours, locally over 60 liters per square meter (see table below). For the thirsty nature truly a blessing...
Precipitation amount (as of 18:00)
| Measuring stations | Precipitation amount (in mm) |
|---|---|
| Bosco/Gurin (1486 a.s.l., TI) | 61 |
| Faido (747 a.s.l., TI) | 61 |
| Grono (325 a.s.l., GR) | 60 |
| Bülach (403 a.s.l., ZH) | 56 |
| Innerthal (903 a.s.l., SZ) | 53 |
| Flühli (884 a.s.l., LU) | 52 |
| Vicosoprano (1089 a.s.l., GR) | 51 |
| San Bernardino (1639 a.s.l., GR) | 48 |
| Soglio (1086 a.s.l., GR) | 48 |
| Robbia (1078 a.s.l., GR) | 47 |
| Oron-la-ville (830 a.s.l., VD) | 46 |
| Biasca (307 a.s.l., TI) | 45 |
| La Valsainte (1044 a.s.l., FR) | 44 |
| Trun (834 a.s.l., GR) | 43 |
| Wädenswil (463 a.s.l., ZH) | 43 |
| Güttingen (440 a.s.l., TG) | 42 |
| Comprovasco (575 a.s.l., TI) | 41 |
| Cevio (416 a.s.l., TI) | 41 |
| Mosogno (771 a.s.l., TI) | 39 |
| Rickenbach Sulz (462 a.s.l., ZH) | 38 |
Outlook: Further downpours and thunderstorms
It is not over yet with the showers and thunderstorms, especially in the evening and at night more are expected with emphasis in the Alps, the number of lightning and the precipitation totals continue to increase. Tomorrow, Thursday, there will still be thundery showers, especially in the morning and in the foothills of the Alps, then it will dry up everywhere and the thundery phase will be over.
60'000 flashes in 24 hours
The number of lightning bolts continues to increase by the minute. Since yesterday, about 60,000 light ning bolts have now discharged over Switzerland. This is a very large number of lightnings. It does not happen to this extent every summer.
For comparison: Last year there were almost 85'000 lightnings in the whole month of July. In the entire year 2023, the lightning counter currently stands at a total of about 200,000 flashes. The following graphs show the temporal course of lightning from yesterday and today (until noon). This afternoon and evening, more thunderstorms will pass over Switzerland, an overview is shown in our precipitation radar.
Fig. 1: Lightning history from July 11, 2023; Source: MeteoNews AG / UBIMET
Fig. 2: Lightning history from July 12, 2023 (until noon at 12:50); Source: MeteoNews AG / UBIMET
Until the morning partly somewhat larger precipitation totals
After June, which was much too dry in the north, and July, which has also been much too dry so far, precipitation was very welcome for nature; this has now fallen in somewhat larger amounts in some areas with the downpours and thunderstorms in the last 12 hours. As a result of the thundery weather, however, the precipitation distribution is very different. Thus, there were locally up to more than 40 liters of rain per square meter and in Bosco-Gurin even 60 liters, but locally also less than 5 liters (see the following map for the precipitation distribution over the area as well as hit list with the stations with the largest amounts of precipitation).
Fig. 1: Precipitation total until 7 am this morning; Source: MeteoNews, Ubimet
Precipitation amount (as of 07:00)
| Measuring stations | Precipitation amount (in mm) |
|---|---|
| Bosco/Gurin (1486 a.s.l., TI) | 60 |
| Flühli (884 a.s.l., LU) | 46 |
| Grono (325 a.s.l., GR) | 46 |
| Oron-la-ville (830 a.s.l., VD) | 44 |
| Faido (747 a.s.l., TI) | 44 |
| San Bernardino (1639 a.s.l., GR) | 43 |
| La Valsainte (1044 a.s.l., FR) | 41 |
| Comprovasco (575 a.s.l., TI) | 39 |
| Biasca (307 a.s.l., TI) | 38 |
| Cevio (416 a.s.l., TI) | 37 |
| Marsens (722 a.s.l., FR) | 34 |
| Plaffeien (1042 a.s.l., FR) | 32 |
| Piotta (1007 a.s.l., TI) | 30 |
| Robiei (1898 a.s.l., TI) | 29 |
| Gütsch (2287 a.s.l., UR) | 28 |
| Kiesen (535 a.s.l., BE) | 28 |
| Zervreila (1738 a.s.l., GR) | 27 |
| Vicosoprano (1089 a.s.l., GR) | 27 |
| Güttingen (440 a.s.l., TG) | 26 |
| Locarno-Monti (367 a.s.l., TI) | 26 |
Further downpours and thunderstorms
Today, Wednesday, there will be some more rain, as more showers and thunderstorms are expected, especially in the second half of the day and in the first half of the night. Towards Thursday morning, there will be another surge of moisture in the north, which will move to the Alps in the morning and slowly subside. Until Thursday evening, the precipitation totals calculated in the following map can be expected.
Fig. 2: Expected precipitation total until tomorrow evening; Source: MeteoNews, Ubimet
The most precipitation is expected along the Alps, where locally more than 30 liters per square meter can be expected. In contrast, the least rain will fall in the Valais (partly less than 5 liters).
Dryness partly somewhat reduced
With regard to the currently quite pronounced drought, especially in the north, the precipitation that has fallen so far and is expected to continue until tomorrow evening will bring some relief regionally. For a total relief, however, much more and longer lasting rain would be necessary. At least, it is possible that by the end of the week the forest fire danger, which is currently considerable to high in the north, will be downgraded regionally.
Already over 50'000 flashes
From Tuesday afternoon until Wednesday morning (as of 06:20), 50'757 lightning bolts have been discharged over the whole of Switzerland. A very large number of lightnings within 12 hours, which is rather rare and occurs only every few years. The last time there was a similar number of lightnings on one day was on June 28, 2021. 2021 was the stormy summer, which brought besides many thunderstorms also floods. Below still the tables with the lightning discharges of July 11 and July 12 (as of 06:20). The number of lightning is a snapshot and will increase significantly today as more thunderstorms move across the country.
Fig. 1: Number of flashes on July 11, 2023; Source: MeteoNews AG / UBIMET
Fig. 2: Number of flashes on July 12, 2023; Source: MeteoNews AG / UBIMET
Gale-force winds and lightning fireworks!
This is a short interim balance of the first thunderstorm season, more thunderstorms are moving in from France in the coming ones. Both the great heat and the thunderstorms following it were announced, and so it has come! From about 17 o'clock more and more thunderstorm cells formed over France, also in our country there were first downpours and thunderstorms – this mainly along the Jura. In the run-up to a massive thunderstorm cluster consisting of several hail cells over France, the activity also picked up speed here. At first, this mainly affected French-speaking Switzerland as well as Ticino and the Gotthard region. The latter thunderstorm area then moved eastward over Graubünden, Glarus and Lake Walen. However, the main part followed further west, several subcells forming a coherent thunderstorm line. This moved across the Central Plateau and central and northwestern Switzerland. This was followed by the greater Zurich area, northeastern Switzerland and the Lake Constance area. In the early stages, there were areas of small-scale hail on Swiss soil, but this gradually disappeared. The thunderstorms were less concentrated in a few cells, but rather grew in width. The thunderstorms were very lightning sensitive, with over 32,000 lightning discharges by 11 p.m.!
Fig. 1: Number of lightning discharges on July 11, 2023 by 11 p.m.; Source: MeteoNews, Ubimet
But the main topic was the wind! Due to the strong high-altitude current, the thunderstorms shifted quickly, in combination with the line-like structure, there were severe squalls at several stations, partly even gale-force gusts – and that even at low altitudes! The front-runner up to the hour was the Uetliberg with a peak gust of 143 km/h, closely followed by the Hörnli with 142 km/h . Attached is a detailed hit list:
Strongest wind gusts (as of 23:15)
| Measuring stations | Strongest wind gusts (in km/h) |
|---|---|
| Uetliberg | 143 |
| Hörnli | 142 |
| Chasseral | 135 |
| Wildspitz | 135 |
| Bantiger | 134 |
| Säntis | 133 |
| Weissfluhjoch/Davos | 130 |
| Wädenswil | 125 |
| Pilatus | 124 |
| Steckborn | 124 |
| St. Chrischona | 123 |
| Salen-Reutenen, Homburg TG | 122 |
| Brülisau-Leugangen | 121 |
| Lucerne | 119 |
| Zurich-Zurichberg | 117 |
| Naluns-Schlivera | 115 |
| Einsiedeln | 113 |
| Napf | 112 |
| Moléson | 111 |
| Cham | 109 |
| Matro | 109 |
| Uttwil | 109 |
| Fahy | 108 |
| Chrüzegg/Atzmännig | 106 |
| Zurich Airport | 105 |
| Piz Martegnas | 105 |
| Altdorf | 105 |
| Bière | 104 |
| La Brévine | 101 |
| Glacier des Diablerets | 101 |
| Crap Masegn | 100 |
| Oberägeri | 99 |
| Schmerikon | 99 |
| Hirzel | 99 |
| Rünenberg | 98 |
| Eggishorn | 98 |
| Sattel | 98 |
| Güttingen | 96 |
| Fribourg-Posieux | 95 |
| Langnau im Emmental | 95 |
| Gütsch | 94 |
| Schiers | 94 |
| Weinfelden | 94 |
| Ebnat-Kappel | 94 |
| Oron-la-ville | 94 |
| Giswil | 93 |
| Koppigen | 92 |
| Berninapass | 92 |
| Bischofszell | 91 |
| Plaffeien | 91 |
Even now during the night, it can pour and thunder again and again. In addition, the cooling due to this first thunderstorm squadron is limited. Here is a snapshot from 22:30: In the Rhine Valley, the thunderstorm gusts mixed the air properly, the temperatures were still at 28 to 30 degrees despite the rain. But even behind the thunderstorms, after a short cooling, it became very warm to hot again – in the greater Geneva area, gusty southwesterly winds also drove the temperatures back up to values around 30 degrees. Even now, one hour later, the values are in this range!
Fig. 2: Temperatures on July 11, 2023 at 10:30 pm; Source: MeteoNews
Attached also the current precipitation amounts until 23 o'clock. In the coming hours, however, these can still change significantly:
Fig. 3: Precipitation amounts on July 11, 2023 until 11 p.m.; Source: MeteoNews, Ubimet
Currently only local hail, but a lot of wind and lightning
After the first local thunderstorms in the early evening, thunderstorm activity has now picked up considerably. In the run-up to a massive thunderstorm cluster over France, more and more new cells have formed. Until recently, we had four hotspots. One between Ticino and the Gotthard region, the second between eastern Lake Geneva and Bern, and two more over the Jura. Meanwhile, the different cells are increasingly organizing lines with a lot of wind. And indeed, there are now squalls at more and more stations! Locally also some hail falls, but at the moment this topic is not in the foreground. The focus is on the wind!
Strongest wind gusts (as of 20:15)
| Measuring stations | Strongest wind gusts (in km/h) |
|---|---|
| La Brévine | 101 |
| Eggishorn | 98 |
| Moléson | 97 |
| Fribourg-Posieux | 95 |
| Oron-la-ville | 94 |
| Gütsch | 90 |
| Marsens | 77 |
| Mathod | 76 |
| Niederscherli | 75 |
| Saignelégier | 74 |
| Glacier des Diablerets | 74 |
| Plaffeien | 73 |
| Payerne | 71 |
| Säntis | 70 |
| Andermatt | 67 |
| Les Charbonnières | 66 |
| Thun | 65 |
| Grimsel | 65 |
| La Dôle | 64 |
| Pilatus | 63 |
Fig. 1: Radar image from 18:10; Source: MeteoNews, Ubimet
Fig. 2: Current lightning discharges; Source: MeteoNews, Ubimet
Hottest day of the year so far, locally up to over 37 degrees!
As expected, there was today Tuesday the hottest day of the year so far, partly the temperatures rose even about 1 to 2 degrees higher than expected and locally even over 37 degrees. It was hottest in Chur with 37.6 degrees, followed by Geneva with 37.4 degrees (see table below). In the north, we partly came close to the July records and absolute records. Thus, the previous July record of 35.4 degrees from July 16, 2003 was surpassed in Vaduz with 35.8 degrees, and the absolute record of 36.0 degrees from August 13, 2003 was only just missed. A July record of 36.5 degrees was also set in Zurich Airport (previously 36.3 degrees on July 7, 2015).
Highest temperature (as of 17:00)
| Measuring stations | Highest temperature (in °C) |
|---|---|
| Chur (555 a.s.l., GR) | 37.6 |
| Geneva (420 a.s.l., GE) | 37.4 |
| Payerne (490 a.s.l., VD) | 37.0 |
| Mathod (435 a.s.l., VD) | 37.0 |
| Zurich Airport (436 a.s.l., ZH) | 36.5 |
| Sion (482 a.s.l., VS) | 36.3 |
| Zurich-Reckenholz (443 a.s.l., ZH) | 36.2 |
| Bern-Belpmoos (510 a.s.l., BE) | 36.0 |
| Würenlingen (334 a.s.l., AG) | 36.0 |
| Bad Ragaz (496 a.s.l., SG) | 36.0 |
| Gösgen (380 a.s.l., SO) | 35.9 |
| Mühleberg (483 a.s.l., BE) | 35.9 |
| Neuchâtel (485 a.s.l., NE) | 35.8 |
| Vaduz (460 a.s.l.) | 35.8 |
| Mosen (453 a.s.l., LU) | 35.6 |
| Beznau (325 a.s.l., AG) | 35.6 |
| Evionnaz (480 a.s.l., VS) | 35.6 |
| Bagnes (820 a.s.l., VS) | 35.6 |
| Buchs-Aarau (387 a.s.l., AG) | 35.5 |
| Lucerne (456 a.s.l., LU) | 35.5 |
After the heat, partly heavy thunderstorms expected
In the evening, it moistens from the west, as a result, partly violent thunderstorms with squalls, heavy rain and locally hail must be expected. Gale-force winds are expected to locally exceed 100 km/h, and gale-force winds (peak gusts of 118 km/h and more) are not ruled out. MeteoNews will keep you informed here.
Classification of the heat expected today
As mentioned earlier, temperatures today, Tuesday, will rise quite widely into the range of near 35 degrees and locally a bit more. However, it will probably not be enough for absolute July records anywhere, even if we come relatively close locally (see table below). Vaduz and Sion are likely to come closest to the July records. Some of the absolute records are even higher. Therefore, we cannot speak of historical heat today, but rather of a very hot midsummer day in the long term.
| Station | expected maximum today | absolute July maximum | July rank 10 | absolute maximum |
| Zurich-Airport | about 34.5-35 degrees | 36.3 degrees | 35.2 degrees | 37.0 degrees |
| Bern | approx. 33.5-34 degrees | 36.8 degrees | 34.6 degrees | 36.8 degrees |
| Basel-Binningen | approx. 34.5-35 degrees | 38.4 degrees | 36.7 degrees | 38.6 degrees |
| Geneva | approx. 36-37 degrees | 39.7 degrees | 37.0 degrees | 39.7 degrees |
| Sion | approx. 36.5-37 degrees | 37.4 degrees | 35.9 degrees | 37.6 degrees |
| Chur | approx. 35.5-36 degrees | 38.1 degrees | 35.6 degrees | 38.1 degrees |
| Vaduz | approx. 34-35 degrees | 35.4 degrees | 34.0 degrees | 36.0 degrees |
| Davos | approx. 27-28 degrees | 29.0 degrees | 27.6 degrees | 29.8 degrees |
| Lugano | approx. 32.5-33 degrees | 37.1 degrees | 33.8 degrees | 37.1 degrees |
In some places tropical night
Last night, temperatures never dropped below 20 degrees in some places, this is called a tropical night. The list below shows the official measuring stations where the temperatures were consistently 20 degrees or more. Numerous stations were also just below 20 degrees.
Lowest temperature (as of 06:00)
| Measuring stations | Lowest temperature (in °C) |
|---|---|
| Vevey | 23.2 |
| Lugano | 22.7 |
| Locarno-Monti | 22.3 |
| Le Bouveret | 22.1 |
| Evionnaz | 22.0 |
| Lägern | 21.9 |
| Vaduz | 21.9 |
| Lausanne Pully | 21.8 |
| Gersau | 21.1 |
| Neuchâtel | 20.8 |
| Bad Ragaz | 20.7 |
| Rünenberg | 20.6 |
| Chur | 20.6 |
| Galgenen | 20.3 |
| Stabio | 20.2 |
| Zurich-Zurichberg | 20.0 |
| Sankt Gallen | 20.0 |
After the balmy night, a very hot day is in store today. On the northern side of the Alps, there will be 34 to 36 degrees in the afternoon. Locally, for example in Valais or Geneva, up to 37 degrees are possible. The following chart shows the expected maximum temperatures for today. In the evening, the cooling will follow in the form of partly heavy thunderstorms, see severe weather warnings! We inform continuously here in the ticker.
Fig. 1: Expected maximum temperatures for today 11 July 2023; Source: MeteoNews AG
Monday afternoon widespread over 30 degrees
After rain showers and thunderstorms in the morning, it was quite sunny in the afternoon, the temperatures rose widely to 30 to 32 degrees. The leader was Geneva with 35.1 degrees, second place shared Sion and Biasca with 34.5 degrees. Tomorrow it will be even hotter, the 35-degree mark will be reached at several stations!
Highest temperature (as of 17:30)
| Measuring stations | Highest temperature (in °C) |
|---|---|
| Geneva | 35.1 |
| Sion | 34.5 |
| Biasca | 34.5 |
| Visp | 33.8 |
| Locarno-Magadino | 33.3 |
| Nyon | 33.0 |
| Mathod | 32.6 |
| Grono | 32.6 |
| Scuol | 32.6 |
| Cevio | 32.4 |
| Chur | 32.4 |
| Payerne | 32.2 |
| Stabio | 32.2 |
| Locarno-Monti | 32.1 |
| Vaduz | 32.1 |
| Lucerne | 32.0 |
| Comprovasco | 32.0 |
| Bad Ragaz | 32.0 |
| Zurich Airport | 31.9 |
| Würenlingen | 31.8 |
Today not quite as hot, but humid
In the Jura and northwestern Switzerland, one was awakened in the morning by the first rumblings of thunder or pattering rain, these thunderstorms quickly moved further across northeastern Switzerland. More cells formed over the Jura, which then also moved out into the midlands. In part, there was also small-grained hail.
Fig. 1: Precipitation total from midnight to 11 a.m. today; Source: MeteoNews, Ubimet
In the meantime, the activity has already decreased again. Around noon, there will still be local showers, but otherwise the sun will prevail again in the afternoon in the lowlands. Along the mountains, spring clouds will form, here the risk of downpours or isolated thunderstorms will increase. Compared to yesterday, it will be hotter, but the 30-degree mark will still be cracked. In addition, the air is somewhat more humid, it is humid. The coming night will be slightly cloudy to clear. Temperatures will drop only slowly, it will remain mild. Not necessarily conducive to a restful night's sleep.
Great heat!
Tuesday has some specialties up its sleeve in terms of weather! The day starts with a mostly undisturbed sunrise, and during the day it continues with lots of blue sky. The air mass is exceptionally warm, with zero degrees at altitudes around 4500 meters. The sun will quickly drive temperatures up, in the afternoon it will be supported by a freshening southwesterly wind, or a little Föhn in the Alps. The highs will reach around 35 degrees, but locally it will be a bit hotter. In the Rhone Valley and in the Rhine Valley of Chur, up to 37 degrees. In this range it also goes in the Geneva region, with the southwest wind here even up to 38 degrees are possible!
Fig. 2: Maximum temperatures on July 11, 2023. Widespread up to 35 degrees, but locally even higher; Source: MeteoNews, Ubimet
It is definitely the hottest day of the week, because a cold front is already approaching from the northwest. The mixture of energetic air and the stabilization in the run-up to the front gives reason to fear a turbulent and dynamic development for tomorrow evening and the night to Wednesday. In the course of the evening, the first violent thunderstorms will spread from the southwest and will quickly move northeastward due to the strong high-altitude winds. Hailstorms, intense rain and gale-force winds are to be expected – the full program. During the night, further strong thunderstorms will follow. There is severe weather potential!
Thundery downpours, temperature drop
Downpours and thunderstorms will continue into Wednesday, with the focus slowly shifting to the Alps. Often the clouds dominate, the sun shows rather only in between. Compared to the last days, it is less warm on the northern side of the Alps, there is even a considerable contrast to Tuesday afternoon! There is no question of cool, with highs of 25 to 26 degrees, the temperature level remains summery. On Thursday morning, showers are still possible in the lowlands, but later it will be mainly dry here with a mix of sun and clouds. Along the Alps, further downpours or isolated thunderstorms are on the agenda. Temperatures will reach 26 to 27 degrees.
Fig. 3: Outlook for the coming days; Source: MeteoNews
Sunny again, very warm to hot
On Friday and Saturday, our weather will again be characterized by high pressure, the air in the Alpine region will become drier and warmer again. As a result, the sun will be mostly in charge again, except for veil clouds and spring clouds, the sky will be blue. Temperatures will again approach the 30-degree mark, on Saturday it will be widely and partly clearly exceeded, even from today's perspective.
