IMGW issues first-level warnings for thunderstorms, hail and strong wind across northern Poland
The Institute of Meteorology and Water Management has issued level-one alerts for seven voivodeships on Monday, with the most dangerous conditions forecast for the afternoon.
Warnings issued
On Monday, 15 June 2026, the Institute of Meteorology and Water Management (IMGW) issued first-level meteorological warnings for thunderstorms across a large part of northern Poland. The alerts cover the whole of Pomorskie, Warmińsko-Mazurskie and Podlaskie voivodeships, the eastern half of Zachodniopomorskie, and the northern districts of Wielkopolskie, Kujawsko-Pomorskie and Mazowieckie. The warnings will remain in force from 7:00 until 23:00, with the probability of dangerous phenomena estimated at around 80 percent.
The warnings follow a clear schedule:
- Thunderstorm and wind warnings come into effect for northern Poland
- Afternoon hours: most intense storms and heaviest rain expected
- Coastal strong-wind alerts expire
- All thunderstorm warnings end
What the storms will bring
Thunderstorms moving in from the Baltic Sea and tracking from the north-west to the south-east are expected to bring short but intense spells of bad weather. IMGW forecasts heavy rainfall of around 20 mm, locally reaching 30 mm, and wind gusts up to 75 km/h. Hail is also possible in some places and could damage vegetation or parked vehicles. The most violent weather is expected during the afternoon hours, when the storms will be at their peak.
Coastal wind and hydrological risks
Separate first-level warnings for strong wind have been issued for coastal counties in eastern Zachodniopomorskie and western Pomorskie (including Gryfice, Kołobrzeg, Koszalin, Sławno, Słupsk, Lębork, Wejherowo, Puck and the city of Koszalin). In these areas a westerly wind averaging up to 40 km/h, with gusts reaching 75 km/h, is forecast from 7:00 until 19:00. IMGW has also activated hydrological warnings for rapid water level rises on rivers. In the zones of the heaviest downpours, especially in urbanised catchments and on smaller watercourses, sudden level fluctuations and local flooding may occur.
In areas with forecast thunderstorms, on smaller rivers, especially in urbanized catchments, there may be rapid water level increases and flooding.
Forecast context
The unsettled weather is driven by a filling low-pressure system over the Baltic Sea that is drawing in cool, humid polar maritime air. Maximum temperatures on Monday will range from 14°C in the Suwałki region to around 20°C in the west and south-east. Overnight the storms will gradually fade, though further showery outbreaks are possible on Tuesday in the north-east, where thunderstorms may reappear in the afternoon.
Advice and outlook
IMGW describes the warnings as the lowest in its three-tier scale, but stresses that conditions can still cause material damage and pose risks to health and life. The public has been urged to monitor updated forecasts and exercise caution when outdoors.
We recommend following current forecasts and communications and exercising caution when moving and doing outdoor activities.
