In Finland, ‘hot days’ – also translating to ‘heatwave days’ – are days during which the temperature rises above 25°C. This year, a record number of hot days has been set. On September 5th, the temperature breached the limit of 25.1°C for the 66th time this year, surpassing 2002’s record of 65 hot days. In terms of average temperature, the past meteorological summer (June-August) tied the record warm summer of 1937 with an average temperature of 16.2°C.
Since September 5th, the temperature kept reaching the ‘heatwave day’ limit every day, meaning that at this point (September 8th) we tightened the record to a total of 69 hot days. In the upcoming week, several more hot days are likely to be measured, further strengthening the record. For comparison: an average summer measures 36 hot days.
Record of hot days in May and September
The record number of heatwave days is partially the consequence of anomalously many hot days in both the beginning as well as at the end of the summer.
Specifically, the summer season already started off in record-style, with May measuring 16 hot days. This was more than the previous May-record of 14 hot days measured in May 2018.
The summer is ending in record-fashion too. As of today (September 8), September already measured 6 hot days – one more than the previous September record set in 1968. Most likely, at least a few more hot days will follow in the upcoming days.
The anomalously warm September weather is caused by a high pressure system to Finland’s east. Thanks to the high pressure, the weather conditions are very sunny, while warm air masses from the south are advected towards Northern-Europe. This pattern will last for – at least part of – next week too.
Scandinavia shatters September temperature records
Finland isn’t the only country in which September started off extremely warm. For instance, up to this year, Norway and Sweden never measured a temperature 30°C in September. On September 5th, the countries broke this threshold for the first time with a national maximum temperature of 30.6°C in Etne and 31.1°C in Lund, respectively.
Lapland record warm
Although the summer in Finland as a whole tied the previous record from 1937, Lapland stood out in particular. Most weather stations in Lapland recorded the highest temperatures in their measurement history. For instance in Tähtelä, Sodankylä, the past summer was 0.5°C warmer compared to the previous record warm summer, with an average summer temperature of 15.9°C.
Besides the unusually hot summer in Lapland and Finland, the summer was record warm in Europe as a whole.
