July and August are the two least windy months of the year in the Red River Valley. July gets the nod for the least windy, but just barely.
Both months' long-term average wind speed is approximately 11 mph. The time of year from July 15 through Aug. 15 is statistically the least windy 30 days of the year, with average wind speeds around 9 mph.
Interestingly, it is this time of year which often brings the strongest wind speeds measured in our region from thunderstorms. However, thunderstorm winds are localized and momentary and so have very little influence on the daily average wind speed.