Composites: Extremely cold May 2025 in Eastern Europe, so far, Iceland (+27°C) and Norway (+29°C) heatwave, next frosts in continental Europe around Friday, Saturday (23.-24. May), heatwaves hit mainly Mediterranean and Eastern Europe, floods in the Alps and Balkan expected

Marek Kučera May 18, 2025 3 min read

May 2025, as you should notice in Mkweather daily weather reports since the start of the month on our homepage, is bringing to parts of Europe anomalously cold weather.

On Sunday, 18. May 2025, the next cold morning appeared mainly in Balkan, Poland and the Alps. From the coldest stations up to circa 1000 MASL, the coldest was in La Brevine, Switzerland, -1,5°C, Sjenica, Serbia, -1,3°C, Suwalki, Poland, -1,2°C, Bugojno, Bosnia and Herzegovina, 0,0°C, Skopje, North Macedonia, 0,0°C.

The period of 1.-16. May 2025 according to ESRL composites was extremely cold mainly in parts of Europe, in Belarus region more than 3°C below temperature average. Cold anomaly is reaching to eastern half Poland, Latvia, Lithuania, Estonia, up to Moscow and Kyiv, and litle weaker anomaly to Romania, Hungary, Slovakia, Czechia, southern Finland and SE Sweden.

Causes of this anomaly we can find in geopotential / air pressure configuration, with a high pressure above the British Islands, Denmark and Norway and a low pressure above European Russia, Eastern Europe, Baltic states and Finland. Between these pressure anomalies, very cold air from the Arctic is flowing to many parts of Europe in May 2025, with frosts and ground frosts even in lowlands.

Meanwhile, in westernmost Europe, is slowly beginning a heatwave, which will be shifting above the continent during June 2025. After +26,6°C in Iceland in the last days, the next hot May days appeared, with up to +26,4°C at the weekend. Grimsey Island and Hornbjargsviti (near the Artcic circle) reported +20,4°C / +20,5°C and the hottest May night in history in the country was measured in Skrauthólar with Tmin of +14,2°C.

In he following days, hot air will shift above Norway, with +28/+29°C, maybe rarely tropical +30°C.

Cold weather will continue above continental Europe until the start of Summer 2025 (Summer 2025 forecast here: https://mkweather.com/summer-2025-forecast-for-europe/), but in the Mediterranean and Eastern Europe, heatwaves are already in the third decade of May expected. In Spain and Sicily, +40°C, in Turkey, +44°C is possible, Ukraine should see +35°C (Central Asia in the last days up to historic +46°C (!!!) /https://mkweather.com/madness-in-central-asia-brutal-heatwaves-up-to-46c-in-spring-turkmenistan-456c-uzbekistan-445c-kazakhstan-440c-siberia-366c-heatwaves-in-the-middle-e//.

Severe storms and floods are prepared mainly for the Alps and Balkan until the start of Summer 2025, with a potential life threat near heavy rains.

June 2025 should finally bring summer and tropical days (above +25°C / +30°C, shortly supertropical days, above +35°C) to continental Europe.

EXTREMELY COLD MAY 2025 IN EASTERN EUROPE, SO FAR

Temperature anomaly in Europe at level 1000 mb in the first half of May 2025 /Source: https://psl.noaa.gov/data/composites/day/

Geopotential (an equivalent for air pressure) anomaly in Europe at level 1000 mb in the first half of May 2025 /Source: https://psl.noaa.gov/data/composites/day/

Precipitation per day anomaly in Europe at level 1000 mb in the first half of May 2025 /Source: https://psl.noaa.gov/data/composites/day/

HEATWAVES IN ICELAND AND NORWAY

That's INSANE, really
Another 26.4C in Iceland 🇮🇸
Records include:
20.4 Grimsey Island
20.5 Hornbjargsviti (near the Artcic circle)

CRAZY MINIMUM 14.2c Skrauthólar
HOTTEST MAY NIGHT IN ICELAND HISTORY

On Monday Norway 🇳🇴will reach 28/29C ! https://t.co/CwbmpX6d9i pic.twitter.com/7rWfCPXyPv
— Extreme Temperatures Around The World (@extremetemps) May 18, 2025