Then it’s autumn
Autumn arrives if autumn temperatures prevail for five days in a row.
Autumn temperature is when the daily average temperature is below ten degrees, but not yet five days in a row.
August 1 has been set as the earliest allowable date for the arrival of autumn.
The latest possible date for autumn’s arrival is February 14.
Source: SMHI
When the daily average temperature has been below 10 degrees for five consecutive days, it is autumn, according to the meteorological definition. Autumn has now crept down to the northernmost parts of Svealand.
Autumn has so far arrived a little jerky this year.
— It arrived in some areas in western Lapland and northwestern Jämtland right at the beginning of August. Then there was a jump to the end of August and the beginning of September when it became autumn in most of Norrland and Dalafjällen, says Sofia Söderberg, meteorologist at SMHI.
That most of the Norrland coast got autumn already at the beginning of September was unusually early, it usually gets there a couple of weeks later.
— There was a period of cool air then, which explains it. Otherwise, autumn has arrived about the time it usually does, says Sofia Söderberg.
Autumn usually comes last to southwesternmost Skåne, usually at the end of October. But then it is often already winter in the northern mountain areas.
“There, it is not unusual for winter to arrive in mid-October,” says Sofia Söderberg.