Historical weather data, all-time temperature records, and monthly climate averages for Portage, WI. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Portage sits right in that awkward shoulder season — expect a chilly 31° overnight with a high around 51°, though history shows anything is possible. This date has swung from a balmy 77° back in 1910 all the way down to a brutal 6° in 1972. There's about a 1-in-3 chance of rain, but snow is unlikely at just 3%.
Portage plays for keeps when it comes to weather extremes — its all-time record high of 111° in July 1936 and all-time low of -37° in February 1918 represent a jaw-dropping 148-degree range. A single storm in August 2020 dumped 7.5 inches of rain, and January 1940 buried the city under 13 inches of snow in one day.
Summer is Portage's sweet spot, with late July highs averaging 85° — ideal if you're chasing warmth. January is the deep freeze, with average highs barely scraping 27°. If you want to dodge the rain, avoid mid-June, which is the wettest stretch of the year at over an inch of precipitation per week.