Poland is heading toward its hottest point of the early-June forecast, with the highest temperatures now expected on 13 June in the west of the country. Near Zielona Góra, thermometers could reach 31 C, the clearest sign yet that the next warm spell will be strongest on the western side of the map.

That is why the forecast is being watched so closely now. The same day is expected to bring 28 C to 29 C in Gorzów Wielkopolski, Poznań, Leszno and the area around Wrocław, while Łódź, Warsaw, Płock and Radom are seen at 27 C to 29 C. The heat is not limited to the west: Kraków, Tarnów, Rzeszów and Katowice are forecast at 25 C to 28 C, and Gdańsk, Olsztyn, Elbląg and Białystok at 25 C to 27 C.

The contrast with the start of the forecast period is sharp. Cooler air is expected to pull temperatures down across northern and western Poland at first, before a clear warming takes hold late in the week. On 5 June, Gdańsk, Koszalin, Szczecin and the area around Słupsk are forecast at about 16 C to 20 C, while the southeast, including Kraków, Tarnów, Rzeszów and Przemyśl, should stay near 24 C to 25 C. Earlier, on 4 June, Poznań, Zielona Góra, Wrocław and Opole already reached 25 C to 26 C, but Zakopane was near 15 C.

The climb begins in earnest on 12 June, when temperatures are expected to rise quickly. In Zielona Góra, Gorzów Wielkopolski, Poznań and Wrocław, the forecast is 24 C to 26 C, and in Łódź, Warsaw, Kraków and Lublin it is 22 C to 25 C. The next day is when the pattern turns into full-fledged upał, with the west again set to lead the country.

That leaves one question open: whether the 31 C reading for 13 June will survive the next IMGW and ECMWF HRES updates. For now, the answer is clear enough for people in western Poland, especially around Zielona Góra. The hottest day in the current outlook is not at the end of the month or buried in a vague long-range trend. It is already pinned to next Friday.