Quarterly climate impacts and outlook for the Gulf of Maine Region: September 2020

Gulf of Maine region significant events – June to August 2020

Long description

The image shows a background map of the Gulf of Maine region, which includes New Brunswick, Nova Scotia, and Prince Edward Island, as well as Maine, New Hampshire, and the eastern half of Massachusetts. Overlaid text highlights significant weather and climate events that occurred in the months of June to August 2020.

The region experienced unusually hot and dry conditions this summer.

Several severe storms produced localized damage in parts of the region during summer.

Summer was hotter and drier than normal across the region. Caribou and Portland, ME; Kejimkujik (National Park), N.S.; and Moncton, N.B., had their hottest summer on record, while Concord, NH; Yarmouth, N.S.; and Fredericton and St. John, N.B., had one of their five hottest. Charlottetown, P.E.I., and Bas-Caraquet, N.B., had their driest summer on record, while several other sites including Caribou, ME, and Summerside, P.E.I., had one of their five driest. Drought developed in the region in June and intensified during summer, with many impacts noted. A few impressive storms, including three tropical systems, moved through the region during summer. See Regional Impacts for details.


There were a few late-season frosts in Maine and the Maritimes during the first half of June. On June 1 and 2, Caribou, ME, tied its June record for greatest number of days with a low of 0°C (32°F) or colder. The Caribou National Weather Service Office issued its first freeze warning for June since 2009. Another frost occurred in the Maritimes on June 10, with northern New Brunswick having below-freezing low temperatures through June 15. The late frosts and summer drought significantly reduced Maine's wild blueberry crop yield.

The region experienced unprecedented heat from June 17 to 24. The hottest temperature recorded in New England was 38°C (101°F) in Penobscot County, ME, while the Maritimes' hottest temperature was 37.3°C (99°F) in Kouchibouguac, N.B. Caribou, ME, and four New Brunswick sites had their hottest temperatures on record for any month. Elsewhere in the Maritimes, high temperatures ranked as the hottest or among the five hottest for June. Preliminary findings indicated that high temperatures caused a train derailment in Saint John, N.B., on June 20. Between June 18 and 23, Caribou recorded four days with a high of at least 32°C (90°F), its second greatest number for June and tied as fourth greatest for all months. Caribou also had its hottest June on record and longest stretch of days with a high of at least 27°C (80°F). This June was the driest on record for several sites including Caribou, ME; Sackville and Bas-Caraquet, N.B.; Amherst and Yarmouth, N.S.; and Summerside, P.E.I., and among the five driest for some other Maritimes sites.


The region experienced hot and humid conditions from July 25 to 29. On July 27, Portland, ME, had a low of 26°C (78°F), its hottest low temperature on record for any month. This July was the all-time hottest month on record for Portland and ranked among the three hottest for Caribou, ME, and Concord, NH. Caribou had its second greatest number of days with a high of at least 27°C (80°F) for any month. Anoxic events in P.E.I. waterways have occurred earlier than usual this year, possibly due to above-normal temperatures.


August featured several rounds of unusually hot and humid weather. Portland, ME, had its greatest number of days with a high of at least 32°C (90°F) for August with six days, contributing to the site having its third hottest August on record.

Regional climate overview – June to August 2020

Temperature: summer departure from normal

Map of temperature departure from normal, averaged over June to August 2020. Temperature normals are based on 1981 to 2010 data.
Long description

The map of summer temperature departure from normal (averaged over June to August 2020), shows that much of the Gulf of Maine region was 1 to 2° C above normal. Parts of eastern Nova Scotia were near normal. Parts of eastern Massachusetts were up to 3° C above normal.

The scale to the right defines the map colours. Shades of red represent positive anomalies (above normal), to +5° C and above. Shades of blue represent negative anomalies (below normal), to -5° C and below. White indicates near-normal conditions (+0.5° C to -0.5° C).

Summer temperatures (averaged over June, July, and August) ranged from near normal to 3°C (5°F) above normal. Through August 31, Truro, N.S., and Moncton and St. Stephen, N.B., had their greatest number of days with a high temperature of at least 30°C (86°F), while several other Maritimes locations including Summerside, P.E.I.; Greenwood, N.S.; and Fredericton, N.B., had one of their five greatest.

June ranged from near normal to 2°C (4°F) above normal, with the warmest locations generally in New England.

July ranged from near normal to 3°C (5°F) above normal, with the warmest locations generally in New England.

August temperatures ranged from near normal to 3°C (5°F) above normal, with the warmest locations generally in eastern Massachusetts.

Daily average temperature departure from normal during summer at Caribou, ME. Warmer-than-normal days are shaded red and colder-than-normal days are shaded blue.
Long description

The time series graph displays the daily average temperature departure from normal during summer (June to August 2020) at Caribou, Maine. It shows:

  • anomalously cold conditions early in June, then closer to normal up to the middle of June
  • sustained above-normal temperatures for most of the period from mid June to mid-August
  • A break in the pattern around mid August with cooler than normal temperatures for the last week of August

The vertical scale on the right in Celsius ranges from -11° (blue shading on graph) to +14° C (red shading).

Precipitation (Summer): percent of normal

Summer precipitation total as a percentage of normal (June to August 2020). U.S. precipitation normals are based on 1981 to 2010 data. Canadian precipitation normals are based on 2002 to 2019 data.
Long description

The map displays total precipitation as a percentage of normal precipitation over summer (totalled over June to August 2020). Conditions were much drier than normal over most of the Gulf of Maine region. The south-central sections of New Brunswick, much of Prince Edward Island, and southwestern Nova Scotia had less than half the normal amount of precipitation.

The scale on the right shows above normal (110% of normal and above) in shades of green, below normal (90% of normal and less) in shades of brown, and near normal (90% to 110% of normal) in white.

Summer precipitation (accumulated from June to August) ranged from 25% of normal to near normal for most areas, except a few Maine sites which were wetter.

June precipitation ranged from less than 25% of normal to near normal for most areas, with the driest locations generally in the Maritimes. However, some sites in western Maine and southeastern Massachusetts saw up to 150% of normal precipitation.

July precipitation ranged from 25% of normal in western New Brunswick and southeastern Massachusetts to 175% of normal in southwestern New Hampshire, western Maine, and Cape Breton, N.S.

August precipitation ranged from 25% to near normal for most areas, except a few Maine sites which were wetter.

Sea surface temperatures (summer): departure from normal

Sea surface temperature (SST) anomalies during summer. SST normals are based on 1985 to 2014 data.
Long description

The map of sea surface temperature departure from normal, averaged over summer (June to August 2020), shows that nearly all marine areas of the Gulf of Maine, Bay of Fundy, and waters south of Nova Scotia were warmer than normal. The main text gives more details.

The scale to the right defines the map colours. Shades of red represent positive anomalies (above normal), to +3° C. Shades of blue represent negative anomalies (below normal), to -3° C. White indicates near-normal conditions (departures near 0° C).

Summer sea surface temperature anomalies over the entire Gulf of Maine were above normal, around 0.75°C (1.3°F) in parts of the Bay of Fundy, from 2.0°C to 3.0°C (3.6°F to 5.4°F) in the western Gulf, and around 3.2°C (5.8°F) over the deeper basins in the central Gulf. Scotian Shelf anomalies ranged from 0.1°C (0.2°F) to 1.0°C (1.8°F). Marine species that typically live in the subtropics, such as the Portuguese man o' war, were seen in the region this summer. The Gulf's waters are warming quickly due to climate change, with studies indicating the changing conditions could negatively affect lobsters' health and cause American lobsters and sea scallops to seek colder waters.

Regional impacts – June to August 2020

Drought Conditions

Moderate drought developed in the region in June and intensified to severe to extreme drought during summer. The Maritimes had the worst drought conditions in Canada as of late August, experiencing extreme drought for the first time since monitoring began in 2002

August 31, 2020 North American Drought Monitor.

Long description

The North American Drought Monitor map for the end of August shows:

  • severe drought over much of New Brunswick with extreme drought over southeastern sections
  • severe to extreme drought over Prince Edward Island and northwestern Nova Scotia
  • moderate to severe drought over southwestern Nova Scotia
  • abnormally dry conditions over parts of eastern Nova Scotia
  • moderate to severe drought over most of New England, except for western Maine which was abnormally dry.

The letters “SL” on the map over the Maritimes indicates both short-term impacts (typically <6 months) (eg agriculture, grasslands) and long-term impacts (>6 months) (eg hydrology, ecology). The letter “S” on the map over New England indicates short-term impacts.

Drought Monitor map categories are:

  • DO (Abnormally Dry), yellow
  • D1 (Moderate Drought), tan
  • D2 (Severe Drought), orange
  • D3 (Extreme Drought), red
  • D4 (Exceptional Drought), dark red

Agriculture: Drought conditions stressed crops and caused some growers to be unable to plant crops. A community garden in P.E.I. that usually yields 20,000 pounds of produce is expecting only 1,000 pounds this year. Potato yields are expected to be reduced by as much as 50% in the Maritimes. Hay yields were down region-wide, by as much as 50% in the Maritimes, with some farmers purchasing feed or selling cattle early. A few Maine farmers applied for an emergency haying and grazing waiver. Use of irrigation was widespread; however, in some locations it was expensive or water supplies ran low or dried up. In addition, drought stress caused leaves to turn color and drop earlier than usual in parts of New England.

Fires: Fire risk was elevated in the region this summer. In June, New Brunswick enacted a provincial-wide fire ban and closed crown lands. By early July, fires had burned through more than five times more acreage of New Brunswick forest than the 10-year average. By late July, Maine had seen around 800 wildfires, the state’s greatest number of fires in a decade. An air quality alert was issued for fires in Nova Scotia, while air tankers aided firefighters in New Brunswick.

June 29, 2020 North American Water Watch streamflow.

Long description

The North American Water Watch stream flow map for June 29, 2020 displays daily streamflow at hydrometric stations compared to historical average streamflows on that date. The map shows that streamflows were much below normal at the majority of sites, with a few stations showing record low streamflows. The exceptions to the pattern were at the boundaries of the regions, including western Cape Breton, western Maine, New Hampshire, and northern New Brunswick, where some sites had near-normal or above-normal streamflows.

The colour of the circular marker at each hydrometric station indicates how the daily streamflow compares to historical percentile classes, with shades of red and orange for below normal (25th percentile and below), green for near normal (25th to 75th percentiles), and turquoise, blue, and black for above normal (75th percentile and above).

Water Resources: In June, dam releases were reduced in New Hampshire due to dropping lake levels, resulting in small hydropower plants no longer being able to generate power. The Aroostook, Penobscot, and St. John rivers had near record low water levels in late July, and there was exposed riverbed in the St. John River in mid-August. York Water District in Maine temporarily siphoned water from Kittery Water District. Some wells went dry in Maine and Nova Scotia. In late August, nearly 300 public water suppliers in Massachusetts and New Hampshire had water restrictions in place, with restrictions also enacted for private wells in a few New Hampshire locations. Warm, dry conditions contributed to the growth of blue-green algae in lakes and rivers in the Maritimes. Health advisories were issued for several locations including the Lake Major watershed, which serves over 103,000 residents in the Dartmouth, N.S., area.

Wildlife: Dry conditions in Maine caused a fungus that kills the pupa of the browntail moth caterpillar to grow too late this year, allowing the caterpillar, which defoliates trees and can cause health problems, to spread farther into central Maine. Another fungus turned drought-stressed grass black. There was an increased number of bear complaints in Maine due in part to dry conditions reducing the bears' food supply. Worms, birds, and aquatic species were affected by the drought in northern Maine. Several dam releases were conducted in the Lamprey River watershed in New Hampshire to help stressed aquatic species.

Summer Storms

Several notable storms moved through the region during summer.

On June 5, severe thunderstorms near Fredericton, N.B., produced estimated wind gusts of up to 130 km/h (81 mph), causing significant tree and property damage. Hundreds of trees were uprooted and some trailer homes were moved or lost sections of their roofs. More than 13,000 customers lost power. Nearly 29 mm (1.14 in.) of rain fell in 15 minutes, making it a 100-yr storm event and resulting in flash flooding and street wash outs.

Storm damage in Fredericton, N.B., on June 5. Credit: Rick Fleetwood
Long description 

Photograph of storm damage in Fredericton, N.B., on June 5. The photograph shows a large uprooted tree in full leaf.

From June 28 to July 1, a stalled storm system brought highly variable rainfall amounts to New England, from less than 3 mm (0.10 in.) in northern Maine to 178 mm (7 in.) in southern Maine. Some locations experienced flash flooding, with closed roads, water in buildings and yards, and cars stuck in floodwaters. The rain temporarily helped alleviate drought conditions in parts of Maine and New Hampshire.

On July 14, hail as large as ping pong balls damaged 1,000 vehicles at a car dealership near Sanford, ME, piling up enough to be plowed off the lot. Nearby, around $10,000 of blueberries were damaged. Heavy rain poured into the hospital operating room in Woodsville, NH, causing dozens of procedures to be cancelled.

On August 22, severe storms in Carroll County, NH, produced an EF-0 tornado, straight-line winds of up to 129 km/h (80 mph), and a waterspout over Lake Winnipesaukee.

Three tropical systems affected the region. On July 11, post tropical cyclone Fay helped spawn an EF-0 tornado in southern Maine.

Tropical Storm Isaias moved through western New England on August 4 and north of the Maritimes on August 5. The storm's highest wind gusts ranged from 64 to 97 km/h (40 to 65 mph). Mount Washington, N.H., had its highest August wind gust of 237 km/h (147 mph). The strong winds downed trees and wires, particularly in New Hampshire where more than 120,000 customers lost power, some for several days. The greatest rain totals of up to 50 mm (2 in.) were in the higher elevations of central New Hampshire.

The remnants of Hurricane Laura combined with another storm system to bring up to 50 mm (2 in.) of rain to the region from August 29 to 30.

Regional outlook – Autumn 2020

Temperature and precipitation

For September to November, NOAA's Climate Prediction Center (CPC) and Environment and Climate Change Canada (ECCC) favour increased chances of above-normal temperatures for the region. Equal chances of below-, near-, or above-normal precipitation were predicted for most areas for September to November, with a tilt towards drier conditions in parts of Nova Scotia and wetter conditions in northern New Brunswick.

Forecast probability of temperature above normal maps for September to November, 2020. U.S. Climate Prediction Center (CPC) temperature map produced August 20 (left). ECCC temperature map produced August 31 (right).
Long description 

Maps of probability of above-normal temperatures for fall (averaged over September to November 2020) for New England (left) and the Maritimes (right).

The forecast for the fall season is for warmer than normal conditions over all areas, with high confidence.

Atlantic Hurricane Season

NOAA's updated 2020 Atlantic hurricane season outlook indicates an above-normal season is most likely, with “19–25 named storms, of which 7–11 could become hurricanes, including 3–6 major hurricanes.” This is due to several factors including warmer-than-average sea surface temperatures and reduced vertical wind shear. By the end of August, there were a record 13 named storms. Four of these storms reached hurricane status, which is above the 50-year average for this time of year. The season runs from June 1– November 30, peaking from mid-August– late October. For more information on the hurricane outlook, see the NOAA Eastern Region Climate Services webinar recording from August 2020.

Quantity Updated 2020 Atlantic outlook (August) Initial 2020 Atlantic outlook (May) Average season
Number of named storms 19 to 25
13 to 19
Number of hurricanes 7 to 11
6 to 10
Number of major hurricanes 3 to 6
3 to 6
Early-September 2020 official probabilistic El Niño Southern Oscillation (EÑSO) forecasts, issued by the U.S. Climate Prediction Center (CPC) and the International Research Institute (IRI) for Climate and Society.
Long description 

The time series graph shows the forecast probabilities of El Niño, La Niña, and Neutral conditions through the next 12 months, as well as the climatological probabilities, produced in early September 2020.

The chart shows that La Niña conditions are most probable for the fall and winter (about 75%), with neutral conditions being most probable next spring.

Vertical bars represent the forecast probabilities. Lines represent the climatological probabilities. The colours blue, grey, and red, represent La Niña, Neutral, and El Niño conditions, respectively. Each bar represents probabilities over 3 months. Each interval overlaps by 2 months. The first 3-month interval is August-September-October 2020. The winter months are in the middle of the graph. The last 3-month interval are the spring/early summer months of April-May-June 2021.

The table below gives the forecast probabilities of La Niña, Neutral, and El Niño conditions for each 3-month interval.

Official ENSO Forecast Probabilities
Season La Niña Neutral El Niño
ASO 2020 73% 27% 0%
SON 2020
77% 22% 1%
OND 2020 79% 20% 1%
NDJ 2020-2021 78% 20% 2%
DJF 2020-2021 74% 23% 3%
JFM 2021 65%
29% 6%
FMA 2021 52% 40% 8%
MAM 2021 38% 50% 12%
AMJ 2021 29% 53% 18%

The climatological probabilities of La Niña, Neutral, and El Niño conditions (solid lines) are as follows:

  • La Niña: about 30% in the fall, 35% in the winter, and about 25% in the spring
  • Neutral: about 40% in the fall, 30% in the winter, and 55% in the spring
  • El Niño: about 30% in the fall, 35% in the winter, and about 20% in the spring

The EÑSO state is based on NINO3.4 Sea surface temperature (SST) Anomaly. The neutral EÑSO is defined as -0.5° C to 0.5° C.

During August, La Niña conditions were observed in the equatorial Pacific Ocean. NOAA's Climate Prediction Center indicates there is a 75% chance La Niña conditions will continue through winter 2020-21.


Environment and Climate Change Canada

Email : ec.enviroinfo.ec@canada.ca

National Oceanic and Atmospheric Administration

Northeast Regional Climate Center

Name: Ellen Mecray

Email: Ellen.L.Mecray@noaa.gov

Name: Samantha Borisoff

Email: sgh58@cornell.edu

Gulf of Maine partners

Receive this publication every quarter

Quarterly Climate Impacts and Outlook Reports – online

Drought report

Report a problem or mistake on this page
Please select all that apply:

Thank you for your help!

You will not receive a reply. For enquiries, contact us.

Date modified: