September Climate Summary

Autumn, my favorite season, accentuates Wisconsin's four season climate. Summer heat is pushed back down south. Days become shorter. A sense of calm sets in as a steady transition of soothing orange, red and yellows appear on the trees. The cool air outside currently cannot let us forget about the dozen beautiful days that preceded our first real taste of cold air this season. The warm, sunny days and cool, clear nights helped create the exceptional fall foliage we see this autumn. They are truly the best weather conditions for great colors.

(Oct-4, 2012)


September was an over achieving month. It recorded below average precipitation staking claim as a top 25 driest of all time. All of Winnebago County is currently in a Moderate Drought condition. September also recorded below average temperatures becoming the first month since September of 2011 to do so.

OSNW3 September 2012 Daily Observations

(click on graph for the month summary data - it will open a new tab/window)

On September 19 the overnight low dipped to 30 degrees at Wittman Regional Airport, breaking a daily record, but the overnight low observed at the Wastewater Treatment Plant, Oshkosh’s official daily climate station, was much warmer at 38 degrees. This single event provokes the idea that perhaps the City Of Oshkosh could be considered an urban heat island. Oshkosh's average first freeze is October 12 and is currently, as of October 9, still awaiting the official first freeze to be observed at the WWTP.

October 1st marks a new year for COOP precipitation observers to begin recording snowfall for another winter season. The average snowfall for Oshkosh in October is 0.1 inches. Oshkosh’s snowiest October occurred in 1929 when 4 inches accumulated. The most recent October snowfall was in 1997, when 1.5 inches fell.

Our days will become 1 hour and 27 minutes shorter by the end of the month.