According to weather forecasts, next weekend will be very warm. Sunday will be the warmest day. In Lahti, about 80 km north of the south coast, the daily maximum will be 17 C. The all-time national record for October is 19.4 C measured in Helsinki on October 2 in 1985. Next Sunday is the 14th day. The length day is about an hour shorter on the 14th of October than on the 2nd of October. Yet, the national all-time temperature record may be broken because the forecast temperature is over one degree higher in the west of the country.
The summer was exceptionally warm and it seems like a gift that keeps giving. But increasingly frequent bouts of unseasonable weather is exactly what you can expect with global warming. Because the polar regions will warm faster than the rest of the globe, the wintertime temperature differential driving the jet stream will be weaker. That will cause the jet stream to meander and guide frontal low pressure centers to move more slowly and along less regular trajectories. That in turn will cause warm air masses to end up in cold regions more frequently than before and vice versa.
@old-guy-photos mentioned temperatures in the 80's (Fahrenheit) or above 28 C in Michigan, USA. Is that very common even there at this time of the year despite the quite southerly location of the state (42 N)?