Already on Tuesday, tropical nights were promised, which means that the temperature does not drop below 20 degrees throughout the day.
The consequences of this are above all at the individual level.
The air does not cool enough during the evening and night to make them cooler indoors.
It's hot all the time, in short.
Risk groups exposed
Tropical nights have no direct effect on nature, the environment and society at large, according to Therese Fougman.
But human distress may require effort.
-People in risk groups who suffer from the heat and have difficulty long for it to be cool.
When it does not, it is extra hard.
In the long run, this can lead to, for example, an increased burden on healthcare.
SMHI has issued a class-1 warning for Gotland with high temperatures - 30 degrees or more - on Tuesday, Wednesday and Thursday.
To all areas in Götaland, Svealand and along the Norrland coast, SMHI sends a message about high temperatures, 26 degrees or higher.
According to SMHI, it is not relevant to raise them to a class 1 warning at the moment.
High pressure on Russia
TT: Why is it so hot now?
-We have warm air over us and have had it in parts of the country for 14 days.
High pressure is over Russia and Finland while Norway and Western Europe have clouds and rain.
Right now, the high pressure is stronger.
The air is constantly heating up over the land mass, so it is warm and continues to be so, says Therese Fougman.
Change is on the way for the northernmost parts of Sweden.
On Wednesday and Thursday, the temperature is still up to 26 degrees.
Then it is expected to drop to a maximum of 20-23 degrees.
Even in Oslo, the night that passed was a tropical night, the first in two years.