The mountain peaks in the extreme north of Sweden, already have winter temperatures, and most parts of the Scandinavian mountain chain now has autumn, which means, after 5 days with average temperatures below 10°C, it is considered to be the beginning of autumn.

Almost half of Sweden already has autumn temperatures (24 hour average), but is still not considered to be the start of the autumn season (they're just autumn temperatures) However, those real autumn might come vey early, if this cool weather more than 5 days.

Which it likely will do, because we are entering a cold phase in Sweden, especially in the north. Also Stockholm could face some really cold day, with a mere max temperature between 11-13°C.

Speaking of low temperatures; Stockholm-Tullinge reported 3.3°C yesterday morning...

Early morning temperatures, 21 Aug 2025

Deviation from normal temperature, 21 Aug 2025

Deviation from normal temperature, 22 Aug 2025

Early autumn

To my observation and interpretation i would say that this weather period it is one of the earler autumn entries in recent history. The chart below looks more like what would be more common after the first week of September. Snow / snow mixed with rain is expected to fall at the higher region in the mountains.

The countdown has started

We might still get 2-4 summery days (>20°) as we enter the month of September, but the litterally stupid computer model prognosis are changing ... all the time, fluctuating back and forth between summer or autumn cold weather. So, in the end it is more like a lottery.

I say generally that after the second week in September, 20°C days in Stockholm start to become rare (but not impossible). Once you enter October, a temperatures of 20°C, are equival to the absolute record in the capital. A rather rare occurance, which i found to happen once every 10 years.