SMHI warns of high temperatures during Wednesday and Thursday as today's highest temperature is expected to exceed 30 degrees in many places.
The rescue service in Eskilstuna, Strängnäs and Flen went out on Tuesday with a recommendation against outdoor fire.
The reason is that it is assessed that there is a great risk of forest fires due to drought in forests and land.
Even in the more coastal municipalities Oxelösund, Trosa, Nyköping and Gnesta, the rescue service advises against outdoor fire.
May be banned from burning
This is not the same as a fire ban, but barbecuers are urged to be careful and have access to water to put out.
Even if there is no fire ban right now, there may be a decision on such in the near future.
- Especially if there is more wind.
Then we get completely different values in forest and land - and then we have a problem.
If that happens, it is highly likely that there will be a fire ban, says Thomas Knutsson at the rescue service in Eskilstuna.
"Take responsibility"
In Katrineholm and Vingåker, the rescue service has not issued any official advice.
- No, we had a fire ban a while ago, but it's gone.
We have not issued any specific advice, but people must take responsibility for what they do, says Lennart Ågren, internal commander of Västra Sörmland's rescue service.
In the clip, Thomas Knutsson tells more about what it looks like in the fields and what a dissuasion about burning outdoors means.