CLIMATE SCIENCE PORTAL CLIMATE SCIENCE 101
Is Maine's weather being impacted by climate change?
‘Climate’ is the patterns of temperature, precipitation, and other meteorological phenomena of a specific region averaged over a long period of time, while ‘weather,’ referring to short term atmospheric conditions, is what we all experience on a daily basis. Weather is when we say ‘It is cold today’ which is a short term condition and climate is when we say ‘Maine summers are usually moderate in temperature’ which is a long term average condition. A changing climate means that we should also expect to experience weather conditions here in Maine that were not at all common in the past as detailed below.
REPORT | University of Maine
Maine is getting warmer
Temperatures are increasing across the state. The average annual temperature has increased 3.2 degrees Fahrenheit (°F) in the last 124 years, with the rate of warming steadily increasing, especially since 1960. The six warmest years on record have occurred since 1998 with 2016 the warmest year on the planet and in Maine.
The Northeast is warming faster than any other region in the U.S., and is projected to warm 5.4 °F (3 °C) as much of the rest of the world warms by 3.6 °F (2 °C). To date, temperature increases in Maine have been greatest in coastal areas.
As Maine’s summers become warmer and longer, the number of excessively hot, humid days when heat indices rise above 95 °F (35 °C) are likely to increase. (The “heat index” is a measure of how hot it feels, taking into account both temperature and humidity.) This graph shows the projected increases in the number of excessively hot, humid days for various locations around the state.
Source: Maine’s Climate Future 2015 ed. p.4 “More Hot Days 2000 to 2050”
Across the state, most of the warmer-than-average temperatures have occurred in the winter, with average minimum temperatures increasing 3.7 to 4.3 °F over the long-term. Warming winter temperatures mean that more precipitation is falling as rain instead of snow. The statewide average annual snowfall is estimated to have decreased by about 17 % over the past century.
INTERACTIVE | Union of Concerned Scientists
KILLER HEAT AN INTERACTIVE TOOL This is an interactive tool that will show the high heat day changes for each Maine county. This analysis shows the rapid, widespread increases in extreme heat that are projected to occur across the country due to climate change.
REPORT | Union of Concerned Scientists
THE FUTURE OF DANGEROUSLY HOT DAYS Includes data and spreadsheets state by state and there are data for each Maine Congressional District.
Maine is getting winter whiplash
In addition to Maine winters becoming warmer, fluctuations between freezing and thawing conditions are becoming more common, with heat waves and rain in the depths of winter, cold snaps and snowstorms in the spring and fall, and Arctic blasts triggering severe snowstorms in the midst of otherwise mild winters. This phenomenon is known as “winter weather whiplash.”
Maine is getting wetter
As Maine warms, it is also getting wetter. Since 1895 Maine’s average annual precipitation (rain & snow) has increased 15% (5.8 inches more water from rain & snow per year), and the rate at which precipitation is increasing is accelerating: Since 1960, it has been more than twice as fast than it was from 1895 to 1960. The greatest increases are experienced in Coastal areas.
Source: Patty Wight/Maine Public "Power out for over 150,000 customers as wind, rain pummel Maine" 2022
GRAPH | University of Maine Orono
EXTREME PRECIPITATION EVENTS This graph shows the annual precipitation in inches recorded at 11 long-term meteorological stations across the state, where an ‘extreme event’ is defined as two or more inches of precipitation (water contained in rain or snow) per 24 hours period. Each bar represents a ten-year interval beginning in 1880 and ending in 2010.
Source: Maine’s Climate Future 2015 ed. p.9 “Extreme Precipitation Events 1880-2010”
Drought incidence might increase in Maine
With an annual average of more than 45 inches of precipitation, Maine is often considered a state with abundant water. Nonetheless, Maine experiences dry periods and episodes of drought, sometimes resulting in major impacts on agriculture (such as the potato and blueberry industries), water resources and communities. The years-long drought in the 1960s had a major impact on agriculture and other aspects of Maine’s economy, as did the much shorter but intense drought of the summer of 2016. We saw similar impacts from the summer 2020 drought. Rivers, such as the Piscataquis seen here, ran very low, and groundwater levels fell making Mainers’ wells more susceptible to drying up.
Forecasting the future of drought in a warmer Maine is difficult. Rainfall is projected to increase (and already has as shown above), but much of that additional moisture will run off into aquatic habitats during the more intense precipitation events. Higher temperatures will lead to more evaporation of water from the land. We’ve also already seen more volatility in precipitation, that is, more extreme periods of dryness and wetness. All of these factors suggest that Maine will likely experience more drought in the future. This is an area of Maine climate change research that deserves much more attention from scientists.