Polar air, clear skies, and lengthening nights produced a cold Friday morning across Switzerland, with first frost recorded even in lowland areas (e.g., Ruswil, Lommis) and temperatures dropping to –8°C in the Engadine. Such cold nights are less likely in October, per Zurich’s ensemble forecasts.

“We are the most intellectual species to walk the planet, but we’re not intelligent. If you’re intelligent you don’t destroy your only home.” Dr. Jane Goodall

Monthly global climate data update from @copernicusecmwf.bsky.social ERA5 for the month of September 2025. Third hottest month of September since 1940. #climate datagraver.com/climate-data...

Now that Imelda is an extratropical cyclone and there's a break in the activity, here's a look back at the tracks of all 9 named storms so far this season. Their peak intensity, minimum pressure, and total Accumulated Cyclone Energy are listed on the right.

[1/2] 📢 GLAMOS @scnat.ch press release out today: Swiss glaciers lost another 3% of their volume in 2025, the 4th-largest decline ever measured. In just 10 years, they’ve lost a quarter of their ice mass. Over 1k small glaciers have already vanished. 🔗 to press release: scnat.ch/en/uuid/i/9d...

Can you spot the Polarstern amid the ice floes of the Arctic? 🧊A satellite image shows, that we are just a pixel amidst ice floes (light grey) and open water (dark). Polarstern appears as a bright spot in the image because it reflects electromagnetic radiation more strongly than its surroundings.

Again dry and often sunny autumnal weather prevails across Switzerland: the sun has re-emerged over the eastern pre-Alps for the first time since Monday! In the Alps, fresh snow is observed above 2000 metres, as indicated by the blue shading.

The post-tropical storm Gabrielle passed west and north of the Azores overnight into Friday morning. MTG3 satellite and radar data from 0700 UTC. Only higher elevations (e.g., Pico Alto) reported hurricane-force gusts, with Flores recording approximately 100 mm of rainfall.

As September 2025 is drawing to a close; below are the projected temperature anomalies for October, as simulated by 13 weather models. Additionally: a very first outlook for the winter of 2025/2026 is now available ↘️

Despite the recent cool spell, including fresh snow down to 2,000 m on Wednesday morning, September 2025 in Switzerland is projected to be average (western regions) to 1 °C above average in temperature. Across Europe and globally, the month has been significantly warmer than average.

Fresh #snow is visible on several of our #glaciers through the real-time stakes, and more is on the way. ❄️ Winter is coming, marking an important recovery phase for glaciers after the (big) summer melt.

Reminder, every location on this map has > 12 hours of daylight and < 13 hours of daylight; therefore, there are no lines on the map representing whole hour increments (no 12 hour line, no 13 hour line, and no other hourly lines). The "equilux" is September 25th.

CAT3 hurricane GABRIELLE will cross Acores Thursday night/Friday morning, according to GDM+ECMWF ensembles above all the western and northern island with up to 100 km/h. Saturday storm will weaken fast, remnants bring plenty of rain to Portugal til Sunday.

Lightning flashes around the strong eye of a category 4 Hurricane Gabrielle.

Tropical storm GABRIELLE is forecast to become a hurricane by Sunday and pass east of Bermuda Sunday night and Monday. Afterwards fish storm Gabrielle will move to north and northeast, according to ECMWF- and Google GDM ensemble ML model.

Tropical storm GABRIELLE struggling over central tropical Atlantic...but should become better organized over the weekend and move then as a fish-storm towards north.

Thursday to Saturday, a subtropical upper-level ridge brings sunny, dry, clear, and very warm weather to the Alps. On Friday, freezing level rises to 4500–5000 m: yet no September mid-month record: Zugspitze had 1947 13.3 °C, some stations then up to 36 °C!

First half of first autumnal month September 2025 in Europe: too warm in eastern/northern and too wet in central Europe.

First 10 days of first month of climatological autumn: too cold in southweatern, too warm in eastern/northern Europe. and too wet in central Europe... by JMA

This year's measurement of Kebnekaise's southern peak by @tarfalaresstation.bsky.social shows that the peak has decreased by 1.5 metres compared to last year. This is the seventh year in a row that Kebnekaise´s southern peak is lower than the northern peak. #Climate #Arctic www.su.se/english/news...

Good morning from Ilulisat🇬🇱 (69.2°N)

UPDATE: Official 12-hourly precipitation data, 09/09/25, 6 UTC. Highest amounts: Bedburg (Germany) 134 mm Luxembourg Airport 122 mm Mönchengladbach (Germany) 122 mm

Tuesday night at the North Cape

This summer, the unusually hot Mediterranean dominated headlines, yet throughout the whole season, the seas surrounding the UK and the Bay of Biscay reached unprecedented temperatures: marine heatwave!

Atlantic hurricane season activity traditionally peaks on or around September 10th - but for the next 7 days no new development is expected! Sub-seasonal forecasts show higher tropical storm probability in week 39...

Since late June, pieces of Iceberg A23a have been breaking off while it drifts near South Georgia Island. The iceberg has decreased in size enough that it is no longer the biggest in the world.

The Antarctic winter (Jun-Aug) averaged 1.0C above the 1991-2020 normal. It was the 12th warmest on record.

A dry and otherwise pleasant Sunday in the Alps, though characterised by very dense cirrus clouds at altitudes of 7 km (over Austria) to 9 km (Switzerland), attributable to WAA+PVA aloft. Suomi NPP/NASA

Friday afternoon, a thunderstorm over the Atlas Mountains (northern Algeria) intensified into an MCC, drifting eastward. By this morning, the system sat east of Tunisia, featuring dramatic high-level cirrus outflows to the north and a dense Saharan dust plume to the south. Credit:EUMETSAT/Eumetview

Summer 2025 in Europe: warmer than usual, among the ten warmest - record warm in western Europe (UK, SPA,POR)

Although August 2025 was too cool in the eastern United States and Europe, globally it was the third warmest since 1940. Credits to @climatologist49.bsky.social

According to ERA5 Reanalysis, this was the warmest summer on record for the United Kingdom. Seems bad. 🔥🔥🔥

Hiring Tips: Have a plan! In order to be a successful candidate, you'll need to explain how you'll help Trump destroy the lives of minorities and migrants! Math and forecasting skill are less important. Preparation is key to being hired! www.sfchronicle.com/politics/art...

The numbers are in. August 2025 was the 3rd warmest August on record globally. No, things are not back to normal. 🔥

We’re filling the atmosphere with CO2 like a bathtub with water. Most of it stays for millennia. That is why the cumulative emissions (the total amount, as pictured here) and not yearly emissions determine the amount of #globalwarming.

75-year September temperature trend for Europe. It's as if something has changed. 🔥

A spectacular "cold wake" is evident along former-hurricane Erin's track. This is a normal feature caused by strong winds upwelling/mixing cooler water from below. Erin was not only very intense but also very large, which also helps with the upwelling. The water temperatures will gradually recover.

Switzerland once again enjoys clear, very sunny and very warm summer weather (>30 °C)! Only tiny cumulus in the south; in the far west some cirrus and haze — a mix of Sahara dust and smoke (N Spain), detected by Payerne ceilometer at 2–4 km.

Erin, now extra-tropical storm, remains a huge cyclone south of Iceland (MTG 10:50 UTC) with record-low seasonal MSLP of 955–960 hPa at 12 UTC and still showing warm-core traits. Faint ash clouds visible over Biscay (from Spain) and behind the cold front (from western USA).

Cool night in Switzerland: not only due to the longer nights, but because of the cooler air that moved in over the weekend. In eastern Switzerland it was the coldest night of the summer, Combe Amburnex in the Neuchâtel Jura even had –3 °C! But 9 July was in most places even cooler ⭕ … Trend Zurich

Wildfires continue to affect northwestern Spain, with smoke plumes extending across the Bay of Biscay and into southwestern France. Additionally, ongoing wildfires in the western United States are generating smoke that is reaching as far as Atlantic Canada (RAP smoke)

A wave train entering into the North Sea, seen by #Sentinel1 on 12 August. I am guessing it's tidal-related, but I have never seen this kind of signal in this region in SAR data before, pretty cool 😎 @jowilliams.bsky.social

End of high-summer period (canicule) brings widespread rainfall across Central Europe, frequently intensified by local thunderstorms. Most precipitation last 24h: >100 l/m² in the southern Black Forest region, while the High Alps received fresh snow (e.g., Klein Matterhorn, 3873 m, −4°C).

Hurricane Erin is Cat 2, may strengthen again. Tracking north off the US East Coast with a vast wind field, bringing local gales, storm surge and rip currents. By Sunday transitioning to a strong extratropical cyclone. Track uncertain: ECMWF favours Bay of Biscay/Ireland, GFS/Google towards Iceland

Even though cooler North Atlantic air will flood into central Europe by Saturday, August 2025 will still end up far too warm overall – except in eastern Europe. And September: most models point to continued warmth, though there will be some exceptions :-)

Sunny and warm again in Switzerland with highs locally above 30°C. Ahead a frontal system from France, a thick aerosol layer of Saharan dust and smoke from Spanish wildfires dimmed the sun. The strange haze was detected by the CHM15k ceilometer in Bern at 4–5 km altitude.

It's still about a month away from official #sunrise at the #southpole, but they are starting to see signs of the Sun on the horizon! Picture by winterover Zeke Mills from the deck on the station! @NSF #southpole

Hurricane ERIN weakened due to internal structural changes, not environmental factors, but is expected to re-intensify by Monday morning (CET)! The system will track as a fish storm far from the US East Coast northwards, undergoing extratropical transition and impacting Europe early next week.

Sunday morning in Europe, as seen by MTG Geocolor imagery: with thunderstorms between Malta and Hungary, early-autumn stratus over Germany and eastern Switzerland, and a dense smoke plume over France from persistent wildfires in northern Spain, obliquely illuminated by low-angle solar radiation.

How fast was Hurricane Erin's intensification rate vs. past Atlantic storms? It wasn't record shattering - but still in the uppermost ranks of Atlantic hurricanes, especially over a 6-hour period: