The highest day temperature in September 2025 was 71°F. The lowest night temperature was 37°F. The average values for day and night temperatures during September were 59.9°F и 51.4°F respectivly.

Most of the days in September are gloomy but you can also expect sunny days.

Precipitation total in September for Joensuu is 2.1 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 8.4 mph. This value is relatively stable throughout the year.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Joensuu in September is 5.6 hours.