The celebration of Walpurgis Day and the King's 80th birthday on April 30 will take place under clear blue skies - the same applies to the demonstrations on May Day. Large parts of Sweden will experience heat on par with temperatures on the Spanish sun coast right now.
A high pressure system is building in and will bring very warm air in tomorrow. It will be warmest in northern Kalmar County and Östergötland, but even as far north as Dalarna there will be temperatures above 20 degrees, says Kjell Lund at SMHI.
Grass fires
But not all parts of Sweden will experience higher temperatures.
It is perhaps in the very far north of Norrbotten that you will not feel the heat.
But the warm weather also brings risks. SMHI is expanding forest and grass fire warnings this weekend to almost all of Sweden except the mountainous regions. There is also a high risk of grass fires in large parts of southern Sweden.
The heat also brings with it a pollen spike.
There will be high levels of birch pollen this weekend, from Götaland, Svealand and a bit up the Norrland coast.
Cold air on the way
It can affect people who usually don't react to pollen.
"We are often very enthusiastic about heat. It's fun, but you won't like it, especially if you have pollen problems," says Kjell Lund.
But the heat will be short-lived. There will be a change in temperature already this weekend.
The high pressure will stay at least until Saturday. Then colder air will return over almost the entire country. The air over the Arctic Ocean is heavy and wants to take over at this time of year.
