IMGW issues dense fog warnings for most of Poland, with visibility below 200 m overnight

Warnings across most of the country

The Institute of Meteorology and Water Management (IMGW) issued first-degree warnings for dense fog on Wednesday, 4 November 2026, covering most of Poland. The alerts take effect at 22:00 on Wednesday and remain in force until 11:00 on Thursday, 5 November. The warning zone covers the whole of świętokrzyskie, łódzkie, wielkopolskie and kujawsko-pomorskie voivodeships, plus parts of ten others: lubelskie, mazowieckie, podkarpackie, małopolskie, śląskie, opolskie, dolnośląskie, lubuskie, zachodniopomorskie and pomorskie. One report gives the total as 14 voivodeships. A regional report puts the start of the Wielkopolska warning at midnight rather than 22:00, a difference the articles do not explain. IMGW's first-degree warnings cover weather that may cause material damage and pose a risk to health and life.

Visibility and the fog forecast

The forecast calls for dense fog with visibility dropping below 200 metres in places, and on roads it may fall below that level. Fog is expected to limit visibility to 100 metres at night in many areas, and hoarfrost may form locally. The institute put the forecast in these terms:

“Dense fog is forecast, with visibility in places below 200 metres.”

For the night from Wednesday to Thursday, cloud cover is mostly small to moderate, though it is large in the north-east. Light rain is possible locally in the Suwałki region. The forecast describes the night as one of freezing fog across much of the country.

Overnight cold and Thursday temperatures

Night minimum temperatures range from -4°C in the south-east and foothill areas to 9°C over the sea. Around 0°C is forecast in several regions, with -1°C in the west and south and up to 2°C in the north. The Wielkopolska forecast puts Poznań at about 0°C around 5:00 on Thursday, and it says thermometers could show negative night values at the weekend. Thursday's daytime highs range from 6°C in the south-east and Sudeten foothills to 11°C over the sea, and about 4°C in the Carpathian foothills. Winds are mostly light, though moderate and gusty north-westerlies are expected in the north-east on Thursday, and gusts of up to 60 km/h are forecast in the Sudetes overnight.

Timing and open questions

Thursday's forecast starts with fog limiting visibility to 200 metres, and locally to 100 metres, with cloud large only where that fog lingers in the morning. Winds ease in the second half of the night and turn variable, except in the north-east. The warnings lapse at 11:00 on Thursday, 5 November. The articles do not say whether the warnings will be extended beyond that time.