When it comes to weather, people differ on the most memorable weather events of the year, notwithstanding something like the Ice Storm of ’98. For 2021, perhaps a lot of Mainers recall the unexpectedly chilly and rainy Memorial Day and July fourth weekends. Or the soaking storms right before and on Halloween. Or maybe the white Christmas most Mainers enjoyed two months ago.
What’s less obvious day to day are the trends, which often aren’t as immediately impressive, but tell us a whole lot about what the future probably looks like. For 2021? To Maine weather watchers it was no surprise. With the year seeing 21 warmth records tied or broken, compared to three cold records broken, the global warming trend continues to here in Maine.
Data-driven climatologists caution that a hot year or even several hot years should not be used to predict trends. “A single extreme weather event is not necessarily evidence of climate change. However, an increasing frequency of events is,” according to Maine state Climatologist Dr. Sean Birkel. “When we consider the changing weather, we have to put that in the context of the long-term trends.”
Birkel continued, “Over the past century, Maine’s climate has warmed by about 3 degrees and there’s also been an observed increase in annual precipitation. This, of course, means that average temperatures and average precipitation amounts are on the rise. These trends are also well represented on seasonal scales.”
The result: Winters are getting increasingly shorter and milder than they used to be, according to the data. Summers have become longer with more warmer days and nights.
The National Weather Service Office at Gray-Portland reported the average temperature for 2021 was 48.8 degrees, 1.3 degrees above normal and the fourth warmest year on record. 2020 gets bragging rights for a record-breaking average temp of 49.4 degrees. The coolest year on record was 43.3 degrees in 1962.
In addition to the warmth records broken in 2021 (see the records accompanying this story), 2021 was the warmest June on record for Portland and was the second warmest June for the state. August was the most humid month since 1950. And the three-month summer period was the second warmest for Portland and the seventh warmest for the state.
October was another warm one: It was second warmest for Portland and fourth warmest for the state.
Also reflecting the warmer temperatures, in part, was the fact that the winter of 2021 was the fifth least snowiest on record with only 33.4 inches of snow. That’s 35.3 inches fewer than normal. Some of what would have been snow fell as rain, but overall yearly precipitation was also lower than normal, with a total precipitation of 44.92 inches, 3.20 inches below normal.
Portland saw below normal precipitation in 10 out of the 12 months, creating a resurgence in drought conditions by early summer. The wettest month was July when remnant tropical systems and summer convection brought a total of 9.44 inches of rain, making it the second wettest July on record. Another wet month was October with 7.18 inches of rain (making it the 10th wettest October on record).
Taking a global view, 2021 tied with 2018 for the sixth warmest year on a record that extends back to 1880, according to NASA’s annual analysis of global average temperatures. The year contributed to an unprecedented, but well-understood trend in which the last 8 years have been the warmest ever recorded. Because this record is global, not every place on Earth experienced the sixth warmest year. However, multiple locales had record-high temperatures, and there were record droughts, floods, and fires around the globe.
SEASONAL HIGHLIGHTS
Winter
A year ago in 2021, southern Maine’s winter had a wimpy start with mild weather and little to no snow on the ground. For the first three weeks of the new year, high temperatures were in the 30s and 40s. There were even a couple nights when the temperature didn’t drop below freezing.
In fact, by the 16th it didn’t feel like January at all when the high for the day in Portland was 48 degrees and 1.41 inches of rain washed away the little bits of snow remaining on the ground.
It was the last week of the month when conditions turned colder and at last there were a few light dustings of snow. On Feb. 2, Groundhog Day, Portland saw its greatest snowfall of the year: 7.8 inches. It was underwhelming compared to Maine winter storms of the past. Expectedly, some residents were relieved while others were disappointed.
Temperatures below freezing coupled with a few more light snow events kept the snowpack at a mere 6 inches through the middle of February. On the 12th, Portland experienced the coldest day of the year when the temperature dropped to 1 degree below zero — the only day of winter 2021 when temperatures went below zero.
Warmer conditions complete with rain punctuated the month, obliterating what little snow had fallen and dashing any hope for typical outdoor winter activities such as ice fishing, skating, and snowmobiling.
March moved in with temperatures fluctuating from well below to well above normal several times. When it was over, the month went into the books with an average temperature above normal and a total snowfall of only 0.1 inch. With a full melt by March 14, winter 2021 could be proclaimed as being officially underwhelming and was the fifth least snowiest on record. Factoring in December of 2020, the winter season was the third warmest on record.
Spring
Not surprisingly after the year’s warm start, the mild trend continued through the spring with both April and May having above normal temperatures.
The last freeze arrived on April 22, one day earlier than in 2020, and one of the earliest on record. It was followed by the year’s first 70-degree day two days later.
The “good news” was that with the one-two-three punch of minimal snowfall, above normal temperatures, and precipitation far below normal, southern Maine did not experience the full-out traditional mud season that we all “look forward to.”
For the second year in a row, because of those conditions, official spring and the accompanying growing season got off to a dry start, bringing with it the concerning return of drought conditions.
You may remember that gorgeously warm day on May 26 when the temperature reached 88 degrees. Or was it the cold, wet Memorial Day weekend that was burned into your memory?
Summer
Early June tried to make up for the holiday weekend washout, starting out of the gate with five straight days of temperatures in the upper 80s to low 90s from the fifth through the 10th.
June’s middle was the coolest part of the month, though the final three days were sweltering as temperatures climbed into the mid- to upper-90s.
The heat wave marked the hottest weather of the year, with the hottest day occurring on June 28 with temperatures tapping out at 97 degrees.
“I would say that June was the most interesting month of the year because of the heat and dryness. Portland had their warmest June on record because of the consecutive hot days along with hot nights. The city recorded three consecutive days with a high of at least 95 degrees for the first time on record in June, also tying for an all-time hot streak for any month. There were 10 record-setting statistics with two additional days where the temperatures tied a previous record,” reported Jessica Spaccio, climatologist with the Department of Earth and Atmospheric Science, Northeast Regional Climate Center, at Cornell University.
This hot, dry pattern led to expanding and intensifying drought conditions, branding June 2021 as having the second hottest maximum monthly temperature, and being the 8th driest, on record. Furthermore, the low of 75 degrees on June 29 was the fourth warmest low temperature on record for that day.
If this pattern felt like déjà vu, it’s because we experienced the same conditions last year in July 2020 and in August of 2019.
As we made our plans for how to stay cool during Independence Day weekend, we were taken aback by Mother Nature once again when she brought us rain and chilly temperatures for the holiday teetering at 65 degrees and below, breaking last year’s record low of 70 degrees. That made two of the coolest Independence Days in 23 years.
On July 5, the low dropped to 49 degrees, the coolest July temperature in nearly 20 years. The conditions weren’t very popular considering we experienced them two holiday weekends in a row.
However, that soaking, paired with the remnants of Tropical Storm Elsa and its 2.33 inches of rain on July 9, helped bring an end to Maine’s ongoing drought conditions. These cooler, wet conditions turned out to be the theme for July 2021, making it the second wettest on record for Portland, where there were 19 days of measurable precipitation.
That weather pattern faded when we turned the calendar to August, which had the hottest minimum monthly temperature since records started being kept in 1895. There were two periods of typical summer heat with multiple days in the upper 80s to 90s along with an extended period of no measurable precipitation. This was interrupted by the remnants of Tropical Storm Fred when almost an inch of rain fell on Aug. 19. And it’s likely no one has forgotten the humidity August offered up; it was the most humid month overall since 1950. It was also the seventh warmest for Portland and the second warmest for the state. Additionally, this Maine summer had the highest minimum coastal temperatures on record.
Fall
In September, the remnants of Hurricane Ida brought nearly two inches of rain on the 1st and second of the month, continuing the trend of post-tropical systems bringing heavy rain to the area.
Mild, dry weather dominated the first half of October with the first freeze of the fall not arriving until the 24th, making this the fourth latest freeze on record. October also logged in as the fourth warmest for Portland and the second warmest for the state overall. At the end of the month, however, the pattern changed to favor Nor’easters.
One of these strong Nor’easters brought rain and winds gusting to 42 mph on Oct. 27, followed by another system bringing heavy rainfall over Halloween weekend. (Holiday weekends drew inclement weather like a magnet in 2021.)
This last blast in October brought the greatest storm total rainfall of the year of 4.17 inches, making it the 10th wettest October on record.
After the Halloween storm, November breezed in with temperatures rising to 60 degrees or greater several times during the first half of the month. More seasonal conditions arrived in time for Thanksgiving along with the first measurable snowfall of (0.1 inches) of the season on Nov. 27.
When the season was done, it turned out to be the third warmest fall (September, October, November) for Portland and the third warmest for Maine overall.
Portland’s first “big” snowfall of the 2021-22 season was on Dec. 18 and 19, when 7.4 inches fell, assuring a long-awaited white Christmas. Over 3 more inches of snow fell on Christmas Day, causing the city and surrounding towns to look like they could star in a Hallmark Christmas movie.
The temperature turned mild for the last week of the year, but the snowpack held.
2021 STATS
Average temperature: 48.8 (1.3 degrees above normal)
Average maximum temperature: 57.6 (1.2 degrees above normal)
Average minimum temperature: 40.1 (1.5 degrees above normal)
Days with temperature of 90 or hotter: 7 (average: 4.6 days)
Days with temperature below 0: 1 (average: 7.7 days)
High temperature: 97, on June 28
Low temperature: 1 degree below 0, on Feb. 12
Total precipitation: 44.92 inches (3.20 inches below normal)
Greatest rainfall in 24 hours: 4.13 inches, on Oct. 30-31
Total snowfall: 33.4 inches (35.3 inches below normal)
Greatest snowfall: 6.7 inches, on Feb. 2
Greatest snow depth: 7 inches on Feb. 20
First frost: Oct. 24
Last frost: April 22
RECORD BREAKERS
The following records were broken or tied in Portland in 2021 for the specific month/day noted:
January: Warmest monthly average low temperature (tied with 1956)
March 15: Coldest high temperature — 21 degrees
March 25: Warmest average temperature — 48 degrees (tied with 1953)
March 26: Warmest low temperature — 43 (tied with 1953)
April 22: Coldest high temperature — 39
May 26: Warmest average temperature — 76
May 29: Coldest average temperature — 47 (tied with 1968)
June 6: Warmest low temperature — 68
June 6: Warmest average temperature — 78
June 7: Warmest low temperature — 64
June 7: Warmest average temperature — 79 (tied with 1999)
June 8: Warmest high temperature — 92
June 8: Warmest low temperature — 72
June 8: Warmest average temperature — 82
June 29: Warmest high temperature — 96 (tied with 1944)
June 29: Warmest low temperature — 75
June 29: Warmest average temperature — 86
June 30: Warmest low temperature — 71
June 30: Warmest average temperature — 83
July 18: Greatest precipitation — 1.17 inches
August: Warmest monthly average low temperature
Aug. 13: Warmest low temperature — 72 (tied with 1944)
Aug. 20: Warmest low temperature — 68
Sept. 24: Warmest low temperature — 63
Oct. 30: Greatest precipitation — 2.78 inches
Dec. 16: Warmest low temperature — 36
Information was obtained from the Annual Climatological Report for Portland issued by the Gray-Portland National Weather Service Office; Sean Birkel, assistant Extension professor, Maine state climatologist at the Climate Change Institute, Cooperative Extension, University of Maine, Orono; Climatologist Jessica Spaccio, Department of Earth and Atmospheric Science, Northeast Regional Climate Center, Cornell University, Ithaca, New York; NASA’s Goddard Institute for Space Studies in New York.
Writer and editor Karen Schneider has been a regular contributor to the Lewiston Sun Journal for over 25 years. Contact her at iwrite33@comcast.net.
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