National Weather Service United States Department of Commerce

***Portland, ME Experienced Its Warmest Year on Record in 2020***

Portland, Maine experienced its warmest year on record in 2020.  The winter was mild with only brief bouts of Arctic cold.  The temperature reached 70 degrees on March 9, the earliest 70 degree temperature on record.  Persistent upper troughs in Spring brought a shift to cooler weather along with frequent storminess.  The cool weather continued deep into Spring with snow being observed as late as May 9.  In mid May, though, the precipitation shut off and drought conditions began to develop heading into the summer.  Very little precipitation fell during a 40 day period from mid May through the end of June.  A slow moving trough finally brought some drought relief at the end of June with showers and thunderstorms dropping more than 3 inches of rain in the final 3 days of June.  After a high of only 70 degrees on July 4, the coolest Independence Day in more than 20 years, Portland saw a sustained period of warm and humid weather.  Portland saw 3 straight days above 90 degrees in late July and again in mid August.  This was the first time Portland experienced a heat wave of 3 consecutive 90 degree days since 2011.  Although there were some periods of 90 degree heat, the warmth was most evident in nighttime low temperatures that often remained in the 70s. The low temperature on July 27 was only 78 degrees, by far the warmest low temperature ever recorded at Portland.  Tropical Storm Isaias brought a brief break from the heat in early August, but also came with 44 mph wind gusts.  A cold front in mid August finally brought the heat and humidity to an end, and the weather was cooler and drier for a while.  The very dry September allowed drought conditions to return.  By mid October more frequent storm systems brought heavy precipitation and occasionally strong winds.  While it was cold and even snowed just before Halloween, another warm up was just around the corner in November. The temperature topped 60 degrees on 7 out of 8 days including a high of 74 on November 7, tying as the warmest temperature on record for November.  As this late season warm spell ended, the stormy weather pattern returned.  A storm on November 30 into December 1 brought 52 mph winds and heavy rain. Less than a week later another storm brought a sticky, wet snowfall along with 49 mph winds.  Cold weather kept the temperature below freezing for 7 straight days, and another intense storm brought nearly 18 inches of snow on December 17.  This didn't last, though, as another strong storm arrived on Christmas Day bringing more rain and wind and washing away all of the earlier snowfall.

The below image represents the yearly observed temperature (blue lines) at Portland compared to the normal temperature range (tan area) and record high/low temps.  This graphic allows you to easily see cold and warm periods through the year with above average temperatures in the red area and below average temperatures in the blue area.  The record hot summer really stands out as almost all the daily lows were above normal and the majority of the high temperatures were above normal.  Interestingly, there weren’t any record high temperatures set through this stretch.  The only period that sticks out as a period of below normal temperatures was during the spring from mid-April through late May.  Another thing that stands us out was the lack of any persistent arctic air during the winter months with a few frigid nights, but only one night through the entire had a sub-zero temperature. 

                                        Portland 2020 Temperature

To look at the top 10 warmest years on record, visit this link: