Historical weather data, all-time temperature records, and monthly climate averages for Portland, ME. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5th in Portland sits in that unpredictable shoulder season — the average high is only 49° with a low dipping to 31°, and there's a 44% chance of precipitation. History keeps it honest: this date has swung from a balmy 70° in 1991 all the way down to a brutal 11° in 1954, so don't put the layers away just yet.
Portland plays for keeps when it comes to weather extremes. The mercury has hit 103° in August and cratered to -39° in February — a jaw-dropping 142-degree swing — and a single October storm in 1996 dumped nearly a foot of rain (11.74") in one day.
Summer is your best bet for warmth, with highs peaking around 79–80° in mid-July before fading through fall. Winters are genuinely cold — January averages just 31° — and late November through early December is the wettest stretch of the year, averaging over an inch of precipitation per week.