The highest day temperature in September 2025 was 93°F. The lowest night temperature was 37°F. The average values for day and night temperatures during September were 77.6°F и 57.9°F respectivly.

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

Precipitation total in September for Spirit Lake is 0.4 in. It makes september one of the least rainy months of the year.

The average wind speed in September is 10.3 mph. It makes September one of the most windless months of the year for Spirit Lake.

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 Spirit Lake in September is 9.2 hours.