Before we delve into the question of whether Wisconsin is getting windier, let’s review some basics regarding wind.
Wind is moving air. Weather reports include observations of wind speed and direction measured at the height of 10 meters (33 feet) above the surface. If the wind speed is strong — greater than 17 mph — and highly variable, the weather report will include the wind gust, which is the maximum observed wind speed.
Wind direction is the direction from which the wind is blowing. A north wind blows from the north toward the south.
One way to answer the windier question is to average the wind speed measured over a city over a year, and so determine the annual wind speed. The change in the annual wind speed over a long period of time indicates the long-term trend in wind speed.
Madison has a record of wind speed observations dating back to 1948. The accompanying graph shows the annual average wind speed for Madison for a given year. The trend is decreasing wind speed over this time period. So, Madison is getting less windy with time.
Observations at Milwaukee also go back to 1948 and show a decreasing trend as well. The wind speed at Eau Claire also has trended slower since 1960s. There is no clear trend for the city of La Crosse.
If we calculate an average wind speed over each month for the entire time period of 1948-2022, we find that the month of April is the windiest with an average wind speed of 11.4 mph. The March average wind speed is 11.3 mph, greater than the February mean of 10.4 mph.
So, with respect to the monthly mean wind speed, March is windier than February and April is windier than March in Madison. After April, the monthly mean wind speed declines. The lowest monthly mean occurs in August, with 7.0 mph.
Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month. Send them your questions at firstname.lastname@example.org or email@example.com.