The warning for high levels, especially during dry weather, applies to all of Götaland and Svealand, as well as the regions along the Norrland coast, according to the Nordic National Museum's website Pollen Report.
In the stretch from Härjedalen and Jämtland north to Norrbotten, the risk of high levels is higher.
Pollen levels generally increase in areas near tall grass around the country. Rain showers occasionally dampen levels, but as soon as the sun comes out, they rise rapidly, according to the site.
The flowering of the grey boletus is also now beginning, and there may be a slight risk of high levels locally, mainly in the south.
The current assessment is valid until Wednesday.
