Historical weather data, all-time temperature records, and monthly climate averages for Mequon, WI. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4 in Mequon sits right on the edge of spring, with an average high of just 49° and lows still dipping to 30°. The date has seen wild swings over 81 years of records — from a balmy 73° back in 1956 to a brutal 13° low in 1995. There's a 40% chance of some precipitation today, though snow is unlikely at just 5%.
Mequon's weather has real teeth at both ends of the thermometer — the all-time high of 104° in July 2012 and an all-time low of -40° in January 1982 represent a jaw-dropping 144-degree spread. August 10, 2025 brought the wettest single day on record with 8.62 inches of rain, while a February 2008 snowstorm buried the area under 15.3 inches in one shot.
Summer is the sweet spot here, with highs peaking around 81-82° in mid-July and staying pleasant through August. Winter is a different story — January and February average highs barely crack the upper 20s to low 30s, so pack accordingly. If you're watching for rain, late June is the wettest stretch of the year, averaging over an inch of precipitation in a single week.