The fire risk is very high to extremely high in southern Sweden and up to Dalarna and Gästrikland. Along the Norrland coast and inland Norrland the risk is assessed to be high or very high, as well as on southern Gotland.
Swedish weather agency SMHI meteorologist Marie Stark said people should be aware that fires can easily start and spread quickly in forests and on the ground.
"Check if there is a fire ban in your area and exercise caution," she said.
By the weekend the fire risk may decrease.
"A few showers are starting to move in over Götaland and Svealand where the risk is greatest. More extensive rain is expected on Saturday and Sunday, which will reduce the fire risk," said Stark.
Scientists have shown that recurring heatwaves are a clear marker of global warming primarily caused by burning coal, oil and gas – and warn they are set to become more frequent, longer and more intense.