The weather in Maine may be below freezing right now, but evidence points to a trend in the other direction.
The average annual temperature in the Portland area last year tied a record set just two years ago, affirming a recent trend of higher temperatures in the region, according to data from the National Weather Service.
Since 1941 — the earliest year that reliable climate data was available for Portland — the annual average temperature is 45.6 degrees. But the number has been higher every year since 2004 and hit 49.2 degrees in 2012, tying the 2010 record.
In fact, Steve Capriola, a meteorologist with the weather service in Gray, said six of the top 10 warmest years on record for Portland are within the last 15 years, but he cautioned against reading too much into the data.
“The trend has been warmer for the last several years, but our data is still new in meteorological terms,” he said. “Things go in cycles, so if we start trending the other way, these numbers won’t mean a heck of a lot.”
The warming trend also holds true elsewhere in Maine and around New England. Bangor saw its 10th warmest year on record with an average of 46.6 degrees. Caribou, in Aroostook County, saw its second warmest year with an average of 42.6 degrees. Farther south, Boston saw its highest average annual temperature in 2012. Concord, N.H., tied a record that had stood for 140 years, Capriola said. Other cities across New England also reported record or near-record warming last year, including Hartford, Conn., Providence, and Burlington, Vt.
Global climate change is still an abstract and controversial concept for some people, but while the cause is being debated, warmer weather is a scientific fact.
“There certainly is an enormous amount of evidence that we’ve been in a warming trend for decades,” said George Jacobson, Maine’s state climatologist. “People don’t see a huge difference in their daily life, but cumulatively, those differences are enough to change patterns.”
Seasonal or monthly data often is more illuminating than annual average temperatures. In nine out of 12 months last year, the median average temperature in Portland was higher than the typical average. Only June, September and November saw slight decreases from the norm.
The average temperature in March of 41.2 degrees was 7.7 degrees higher than the normal average. Some parts of the state saw 70 and even 80-degree days in March, shattering single-day records for that month. January and February were higher than their averages, too, reflecting the overall mild winter most southern Maine residents experienced last year.
The impacts of warmer weather seemed to vary.
Higher temperatures shortened the ski and snowmobile seasons in Maine during the last months of 2011 and the first part of 2012. Mild winters also resulted in late freezing of lakes and rivers, which in some cases led to tragic consequences, Jacobson said. Just last weekend, four people died in snowmobile accidents connected to thin ice or open water.
The mild weather had impacts in less tragic ways, too. It shortened the maple syrup season, both in Maine and elsewhere in the Northeast, and led to less production.
Crops were affected, too. The March heat wave caused many apples to blossom early, but frost in April and May then disrupted the growing cycle. The overall apple crop in Maine for 2012 was about 700,000 bushels, compared to nearly 1 million in 2011.
Maine’s potato crop was affected by weather, too, but more by rain than high temperatures. While the 2011 crop was beset by wet weather that contributed to rot, 2012 was dry, which stunted potato growth. Jim Dwyer, a potato crop specialist with the University of Maine’s Cooperative Extension in Houlton, said gradual warming is not as much of a problem as extreme fluctuations in weather.
David Yarborough, a wild blueberry specialist with the University of Maine Cooperative Extension, said the weather overall in 2012 was good for blueberry production, but weather is only one piece of the puzzle. Even though mild weather is generally good, it sometimes has side effects, too.
“Warmer weather brings more insects and the possibility of disease,” he said. “If there is warmer weather in the fall, next year’s buds don’t harden early enough and that can be a problem.”
A warm winter and wet spring in 2012 also resulted in many more pests attacking gardens across Maine, according to James Dill, a pest management specialist with the UMaine Cooperative Extension in Orono. Some of the pests were perennial pests such as slugs and ticks, but others were pests new to Maine and had the potential to cause major problems for both home gardeners and commercial farmers.
The warmer weather also had some positive effects. An analysis by the Portland Press Herald last October revealed that, as a whole, Maine winters are milder now than they were 100 years ago, especially within the last decade. That means Mainers likely spent less money to heat their homes in 2012.
Staff Writer Eric Russell can be contacted at 791-6344 or at: