Fall 2021

Maine Fall 2021 Climate Summary

By Dr. Sean Birkel, Maine State Climatologist

Highlights

  • The 2021 fall (September–November or SON) was 3rd warmest and 31st wettest since 1895.
  • Abundant rainfall in September and near-normal conditions in October contributed the removal of drought and dryness across nearly all of Maine, with the exception of a contiguous area over western and northwestern along the Quebec border.
  • Global SON average temperature was 4th warmest since 1880, despite persistent cool conditions across the eastern Pacific in association with La Nina.

Statewide Overview

The Maine statewide climatological fall (September-November [SON]) 2021 average temperature was 48.2°F or 3rd warmest on record for the 127-year period beginning 1895 (Fig. 1). This temperature is 2°F warmer than for the same period in 2020, and 4.3 °F above the 1901-2000 historical mean. The observed SON total precipitation was 13.4 inches, or 31st wettest for the record period (Fig. 2). This precipitation amount is 2.4 inches more than for the same period in 2020, and 2.1 inches above the 1901-2000 historical mean.

maps and chart showing Statewide SON average temperature and departure from 1901-2000 baseline climatology.
Figure 1. Statewide SON 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.

 

Maps and chart showing Statewide SON total precipitation and departure from 1901-2000 baseline climatology.
Figure 2. Statewide SON 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 SON 2021 season and monthly 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. Data from the NOAA U.S. Climate Divisional Database.
Temp / Anom (°F) Rank Precip / Anom (in) Rank
SON 48.2 / +4.3 3rd warmest 13.4 / +2.1 31st wettest
Sep 59.0 / +4.1 7th warmest 6.5 / +2.8 6th wettest
Oct 50.2 / +5.9 2nd warmest 3.7 / 0.0 61st driest
Nov 35.3 / +3.0 23rd warmest 3.2 / -0.7 41st driest

 

Table 2. Statewide SON 2021 number of daily temperature and precipitation records either tied or broken, as estimated from available stations with at least 30 years of observations. Data from NOAA Daily Weather Records.
Sep Oct Nov SON
Highest Maximum Temperature 0 19 1 20
Lowest Maximum Temperature 0 0 0 0
Highest Minimum Temperature 21 6 0 27
Lowest Minimum Temperature 0 0 0 0
Highest Precipitation 14 7 6 27

 

Drought Greatly Diminished

Abundant rainfall in September (including two extreme events), near-normal rainfall in October (including one extreme rainfall event central/coastal), below normal in November. Drought/dryness removed across almost all of Maine and the Northeast region. Fig. 3, Fig. 4

map and chart showing U.S. Drought Monitor map and regional statistics for November 30th, 2021.
Figure 3. U.S. Drought Monitor map and regional statistics for November 30, 2021.

 

4 graphs showing Daily precipitation accumulation (January–November, 2021) for Portland, Bangor, Rangeley, and Caribou.
Figure 4. Daily precipitation accumulation graphs (January–November, 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.  Year-to-date precipitation deficits are labeled on each chart.  Charts from SC-ACIS developed by the Northeast Regional Climate Center.

Looking Farther Afield

The SON 2021 global average near-surface temperature ranks 4th warmest on record since 1880 (Fig. 5). A map of the global distribution of SON temperature anomalies shows particularly warm values over eastern Siberia and the Canadian High Arctic (Fig. 6). The prominent pattern of cool anomalies off the western margins of North and South America and stretching across the equatorial Pacific are associated with La Niña, which will affect winter climate globally for a second year in a row (Fig. 7). It is notable that despite the persistence of La Niña, global mean temperatures remain historically high. In the Arctic, the sea-ice extent at the end of November has bucked the trend of recent years and is the most extensive since 2014 (Fig. 8). The 10.83 million km2 areal sea ice coverage ranks 13th lowest since continuous satellite observations began in late 1978.  For comparison, late November sea ice extent in 2020 was 2nd lowest on record.

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

 

Map showing SON 2021 worldwide near-surface air temperature anomalies
Figure 6. Map showing SON 2021 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.

 

Map showing SON 2021 worldwide sea surface temperature anomalies
Figure 7. Map showing SON 2021 worldwide sea surface 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.

 

Chart showing timeseries of daily sea-ice extent (>15% ice coverage at each gridcell) across the Northern Hemisphere measured by satellites since 1979.  Maps comparing sea ice extents on November 30th, 1980 and 2021.
Figure 8. (top) Timeseries of daily sea-ice extent (>15% ice coverage at each gridcell) across the Northern Hemisphere measured by satellites since 1979.  (bottom) Maps comparing sea ice extents on November 30th, 1980 and 2021. 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.