Historical weather data, all-time temperature records, and monthly climate averages for Muskego, WI. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in Muskego sits right on the edge of winter's retreat — the average high is just 50° with lows still dipping to freezing. It's a date that has seen everything from a balmy 78° back in 1929 to a brutal 15° in 1979, and there's still a 1-in-14 chance of snow falling today.
Muskego's weather history is a study in extremes: 128 years of records stretch from a scorching 109° in July 1936 all the way down to -28° in February 1996 — a swing of 137 degrees. A single day in August 2025 dropped 6 inches of rain, and January 1918 buried the area under 20 inches of snow.
Summer is the sweet spot, with highs peaking around 83-84° in mid-July before a gradual fade through fall. Winters are genuinely cold — expect highs only in the upper 20s in January, with February capable of record-shattering lows. If you're worried about rain, pack an umbrella for late June, the wettest stretch of the year.