Meteorological autumn has officially arrived in Latvia, though today brings warm weather
Latvian meteorologists confirm that meteorological autumn has begun this year, yet Riga will still see a warm, dry day with highs of +19 degrees. This year's onset came later than in 2025 but earlier than the long-term average.
Data from the Latvian Environment, Geology and Meteorology Centre show that meteorological autumn has now begun across the country. September 10 is considered the starting date, since the nationwide daily average air temperature has stayed below +15 degrees for five consecutive days from that point — the standard threshold used to mark the seasonal shift. As recently as September 9, temperatures had reached +27 degrees before dropping sharply.
On Monday, September 14, the national average temperature climbed to +14.8 degrees, though this figure remains preliminary, as it is based on operational data that has not yet undergone quality control.
Today's forecast
Despite autumn's arrival, Monday's weather in Riga is expected to stay pleasant: no precipitation is forecast, winds will be light, and sunshine should push temperatures up to +19 degrees. The conditions are being shaped by an area of high atmospheric pressure, measured at 1020–1021 hectopascals at sea level.
Compared with previous years
Over the 1991–2020 reference period, meteorological autumn in Latvia typically begins on August 31 on average, meaning this year's onset is slightly later than usual. Last year the season began unusually early, with the qualifying cold spell running from August 20 to 28. In 2023, by contrast, the record for the latest-ever start to meteorological autumn was set, with the season not beginning until October 4.
Seasons can be defined in several different ways. Calendar autumn always runs from September 1 to November 30, while astronomical autumn will begin this year on September 23. Solar autumn, based on dividing the year by daylight periods, already started on August 6.
While earlier forecasts pointed to a warm, wet autumn, the latest data from the European Centre for Medium-Range Weather Forecasts now shows a rising likelihood of drier and cooler spells as well this season.
