Climate in Sammatti is mild and humid for most part of the year. This region of Finland does experience four distinct seasons.
Spring (April to May): In this season, the temperature during day hours remain slightly warm. But the nights turn out to be cooler because of fall in the temperature. Hence, if you are visiting Sammatti in this season, carry few layered clothes to keep yourself warm. As far as rainfall is concerned, its level is quite low as compared to the other seasons.
Summer (June to August): The temperature drastically rises up in this season. July is the hottest month of the year. Days are quite clear and the nights are as usual a bit cold. If you can bear the scorching heat of the day hours, then this off-season can also be chosen as the time to visit Sammatti.
Autumn (September to October): Like spring, autumn is another favorite season for tourists to visit Sammatti. Though the level of precipitation slightly rises up. Still the pleasant temperature makes the climate quite favorable for exploration.
Winter (November to March): Winter is as usual very cold. The temperature sometime goes below 0 degree Celsius. Added to this, occasional showers do take place, which makes the weather extremely cold.
Thus, spring and autumn turns out to be the best time to visit Sammatti. However, both these seasons are the peak seasons for Sammatti. Hence, expect high price in hotel deals and lots of tourist crowd at the tourist spots. So, if you wish to avoid the crowd summer can be your option.