As fall progresses, we can expect more windy days. Although summer thunderstorms produce the winds which are most likely to be destructive, these winds are brief and usually spread over relatively small areas. Otherwise, most summer days are relatively calm with average wind speeds around 11 mph. However, fall brings powerful, large-scale weather systems. These have much greater pressure differences, and so we get more frequent windy days.
Average wind speed, along with the frequency of windy days, steadily increases through the fall, peaking in November. November winds average over 13 mph, and it is not unusual for 30 mph winds or greater to persist for eight to 12 hours or more. During December, the average daily wind speed drops a little, but it begins increasing again through the winter and spring. April is the windiest month with an average wind speed of 14.4 mph.