Historical weather data, all-time temperature records, and monthly climate averages for South Portland, ME. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 4 in South Portland is a coin-flip for rain — nearly a 50% chance of precipitation — with temperatures that can go almost anywhere. The date has seen a balmy 76° (2010) and a brutal 8° (1954), a 68-degree spread that captures early spring's unpredictability perfectly. Expect something in the middle: an average high of 48° and a low that still dips to freezing.
South Portland's weather has real teeth — 103° in August 1975 and -39° in February 1943 represent a jaw-dropping 142-degree swing between the all-time extremes. The wettest single day on record dumped 11.74 inches in October 1996, and a December 1970 storm buried the area under 22.3 inches of snow. This is a place that earns every season.
Summer peaks in the third week of July with average highs around 80°, while mid-January bottoms out at a frigid 30° — a full 50-degree seasonal swing. If you're visiting for warmth, aim for July or August; if you want to avoid the worst weather, sidestep late November through early December, the wettest stretch of the year. Spring and fall offer mild temperatures but come with real precipitation risk.