Historical weather data, all-time temperature records, and monthly climate averages for Germantown, WI. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Germantown sits squarely in that unpredictable shoulder season — the average high is just 49° with a low of 30°, but 81 years of data show this date can swing wildly. It's reached 73° (1956) and bottomed out at 13° (1995), so don't put the winter coat away just yet. There's a 40% chance of precipitation today, with a small but real 5% chance it falls as snow.
Germantown's weather has a serious range — from a brutal -40° in January 1982 to a scorching 104° in July 2012, that's a 144-degree spread over the station's history. The wettest single day on record dropped 8.62 inches on August 10, 2025, and a February 2008 storm buried the area under 15.3 inches of snow in one shot. This is a place that earns every season.
Summer is the sweet spot, with highs peaking around 81-82° during the third week of July — warm, but rarely oppressive. Winter bites hard: January highs average just 27°, and the coldest stretch of the year runs mid-January through mid-February. If rain is a concern, late June is the wettest stretch of the year, averaging over an inch of precipitation in a single week.