Calendar Year 2021

Maine 2021 Calendar Year Climate Summary

By Dr. Sean Birkel, Maine State Climatologist

Highlights

  • The 2021 calendar year was 2nd warmest and 39th driest in Maine based on observations beginning 1895.
  • While most of the state has seen near-normal annual accumulated precipitation this year, moderate to severe drought persists across an area of northern Oxford, Franklin, and Somerset counties along the Quebec border.
  • Global 2021 calendar year average temperature was 6th warmest based on observations beginning 1880, despite persistent cool conditions across the eastern Pacific in association with La Niña.

Statewide Overview

The Maine statewide 2021 calendar year (annual) average temperature was 44.2 °F, or 2nd warmest on record for the 127-year period beginning 1895 (Fig. 1). This temperature is 0.7 °F warmer than for the same period in 2020, and 4.1 °F above the 1901-2000 historical mean. The observed annual total precipitation was 39.3 inches, or 39th driest for the record period (Fig. 2). This precipitation amount is 1.3 inches less than for the same period in 2020, and 2.7 inches below the 1901-2000 historical mean.

Figure 1. Statewide annual average temperature and departure from 1901–2000 baseline climatology. Data from NOAA U.S. Climate Divisional Database and nClimGrid. These charts are also available on the Maine Climate Office website.

 

Figure 2. Statewide annual total precipitation and departure from 1901–2000 baseline climatology. Data from NOAA U.S. Climate Divisional Database and nClimGrid. These charts are also available on the Maine Climate Office website.

 

Table 1. Statewide 2021 annual (January–December) and seasonal temperature and precipitation statistics. Rankings are for a 127–year record period. “Anom” refers to anomaly, or the departure from the 1901–2000 historical mean. Note that the annual statistics are for the calendar year January – December 2021, whereas the DJF statistics are for the contiguous winter months December 2020 – February 2021. Data from the NOAA U.S. Climate Divisional Database.
Temp / Anom (°F) Rank Precip / Anom (in) Rank
Annual 44.2 / +0.7 2nd warmest 39.3 / +2.1 39th driest
DJF 22.4 / +6.8 3rd warmest 10.1 / +2.8 46th wettest
MAM 41.7 / +3.4 7th warmest 8.0 / 0.0 24th driest
JJA 65.6 / +2.9 4th warmest 10.3 / -0.8 49th driest
SON 48.2 / +4.3 3rd warmest 13.4 / +2.1 31st wettest

 

Table 2. Statewide 2021 seasonal number of daily temperature and precipitation records either tied or broken, as estimated from available stations with at least 30 years of observations. The DJF statistics are for the contiguous winter months December 2020 – February 2021. Data from NOAA Daily Weather Records.
DJF MAM JJA SON
Highest Maximum Temperature 52 55 78 20
Lowest Maximum Temperature 2 37 29 0
Highest Minimum Temperature 34 73 169 27
Lowest Minimum Temperature 0 1 10 0
Highest Precipitation 65 19 28 27

 

Drought Status

Despite some signal carryover from the 2020 drought and precipitation deficits in the first half of the year, the observed accumulated precipitation for calendar year 2021 is near normal (but with small deficits ranging 0.9 to 3.7 inches) in Bangor, Caribou, and Portland (Fig. 3).  In sharp contrast, observations at Rangley show a precipitation deficit of 15.5 inches.  These observations are reflected in the U.S. Drought Monitor where moderate to severe drought persists across an area of northern Oxford, Franklin, and Somerset counties along the Quebec border (Fig. 4). Abnormal dryness also extends across northern Piscatiquis and western Aroostook counties. Snowfall over the remainder of winter and snowpack/snowmelt in spring will be important factors in determining the hydrologic conditions when the warm season arrives.  The latest drought information is available from the Northeast Drought Early Warning System (DEWS).

Figure 3. Daily precipitation accumulation graphs, January–December 2021, for Portland, Bangor, Rangeley, and Caribou. The brown line indicates normal values for each site; green line shows 2021; and the red line shows values for the record driest year. Charts from SC-ACIS developed by the Northeast Regional Climate Center.

 

Figure 4. U.S. Drought Monitor map for January 4th, 2022.

 

Looking Farther Afield

The 2021 annual global average near-surface temperature ranks 6th warmest for the period of observations beginning 1880 (Fig. 5). A map of the global distribution of annual temperature anomalies shows particularly warm conditions across eastern Canada and the high latitudes of the North Atlantic, as well as Algeria, portions of the Middle East, and Antarctic Penninsula. Cool anomalies are found primarily over Australia, part of West Antarctica, and across the eastern equatorial Pacific and off the western coast of South America (Fig. 6). The cool anomalies over the Pacific are associated with La Niña, which has affected global weather patterns since late 2020 (Fig. 7). It is notable that despite the persistence of La Niña, global mean temperatures remain historically high. In contrast, Arctic sea ice extent bucked the trend of recent years and ranks only 18th lowest for December 31st for the satellite observation era (Fig. 8). Arctic sea ice extent at the end of 2020 was 5th lowest.

Figure 5. Global mean annual temperature anomaly time series. Image from NOAA/NCEI Climate at a Glance.

 

Figure 6. Map showing 2021 annual worldwide near-surface air temperature anomalies (1951-2000 climate baseline) estimated by the European Centre Reanalysis version 5 (ERA5). Images from the UMaine Climate Change Institute’s Climate Reanalyzer.

 

Figure 7. Map showing 2021 annual sea surface (SST) anomalies (1951-2000 climate baseline) across the Pacific Ocean. SST estimates by the European Centre Reanalysis version 5 (ERA5). Images from the UMaine Climate Change Institute’s Climate Reanalyzer.

 

Figure 8. Timeseries of daily sea-ice extent (> 15% ice coverage at each gridcell) across the Northern Hemisphere measured by satellites since late 1978 (top). Maps comparing sea ice extents on December 31st, 1978 and 2021 (bottom). The sea ice time series data are from the NOAA/NSIDC Sea Ice Index and maps from the NCEP Climate Forecast System model. Both visualizations are available on the UMaine Climate Change Institute’s Climate Reanalyzer.

 

Maine historical climate data and current weather forecasts are available on the Maine Climate Office website. For U.S. and global climate and weather data, visit Climate Reanalyzer. The Maine Climate Office and Climate Reanalyzer are developed and maintained by Dr. Sean Birkel, the Maine State Climatologist and Assistant Extension Professor at the Climate Change Institute and Cooperative Extension at the University of Maine.