Historical weather data, all-time temperature records, and monthly climate averages for Duluth, MN. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4th in Duluth is a classic late-winter transition day — expect something in the low-to-mid 40s with a decent shot at overnight lows still dipping into the 20s. The date's range tells the real story: it's hit 73° (1929) and bottomed out at exactly 0° (1995), which is about as wide a spread as you'll find anywhere in early spring.
Duluth plays for keeps on both ends of the thermometer. The city has swung from a brutal -38° in February 1967 all the way up to 105° in July 1936 — a 143-degree range that reflects just how much weather Lake Superior's influence can and can't soften. A single February storm in 2001 dropped 18 inches in one day, which should surprise exactly no one who's spent a winter here.
Summer is short but real in Duluth — late July peaks around 79° and June brings the heaviest rain, averaging over an inch in its wettest week. The cool season is long and serious, with January highs averaging just 21° and the thermometer not reliably clearing 40° until April. If you're planning a visit, the sweet spot is July through early September before the lake breezes start carrying a bite again.