Massachusetts Climate – July 2026 Update
Top 5 Cities: Boston, Worcester, Springfield, Cambridge, and Lowell
Summary
July brought a deluge to Massachusetts, marked by torrential downpours, flash flooding, and air quality alerts from Canadian wildfire smoke alongside local fire activity. While local temperatures were only modestly above average, global land temperatures reached near-record heat. Meanwhile, a moderate El Niño in the tropical Pacific is intensifying and forecast to peak at Very Strong in Oct-Dec, with atmospheric conditions expected to maintain elevated storminess and warmth in the coming months.
This month in numbers
Massachusetts recorded 160.53 mm of rainfall (+69.6 mm vs baseline), marking its 8th wettest July in 77 years of records. Average temperatures settled at 21.61°C, placing the month 33rd warmest on record with an anomaly of +0.5°C. Globally, land temperatures reached 15.8°C (+1.6°C anomaly), the 3rd warmest July in 87 years of global observation.
What changed
Over the May to July period, Massachusetts averaged 18.48°C (+1°C anomaly), its 19th warmest such season in 77 years, while afternoon high temperatures reached 24.74°C to rank 15th warmest. This regional moderation stood in contrast to global trends, where the three-month global land temperature reached 14.34°C (+1.5°C anomaly) to rank as the 2nd warmest May to July on record. Across the United States, national temperatures ran +1.5°C above average, while Massachusetts lagged behind its regional group at US Northeast. Over the past 12 months, the state's rolling anomaly of +0.60°C placed it 226th out of 232 tracked regions globally, ranking among the bottom 10 for relative atmospheric warming.
What’s driving change?
Erratic directed heavy tropical moisture across the Northeast, fuelling widespread torrential rains and flash flood threats across southern New England. All of Massachusetts's 3 wildfires this year have happened in the past month, tracked on our live map at Extreme Weather tracker. Global climate dynamics are also being shaped by an active ENSO cycle, with a moderate El Niño recorded in the tropical Pacific, where the Relative Niño Index reached +0.98°C at ENSO. While winter weather in the northeastern United States shows only a modest historical teleconnection to Pacific warming, atmospheric shifts across North America remain influenced by these tropical ocean anomalies alongside broader drivers like .
Looking ahead
Seasonal models indicate an 81% probability of El Niño peaking at Very Strong in Oct-Dec, pointing toward elevated potential for milder temperatures and active storm tracks across New England as autumn approaches.
Sources:
Generated by Gemini from climate data and web sources
At a Glance
Temperature – Average
Climate Map – USUnited States
Source: NOAA Climate at a Glance — US states & climate regions (tavg, pcp), plus GPCC (Snow, water-equivalent). Anomalies are vs the 1961–1990 baseline. See methodology.
Typical Climate – Massachusetts
Köppen Dfa · ContinentalMassachusetts has a continental climate (Köppen Dfa: Humid continental - hot summer), with distinct warm summers and cool-to-cold winters. July is typically the warmest month, averaging 22.7°C, while January is the coldest at -2.0°C. Annual precipitation averages around 1236mm, spread fairly evenly across the year.
Monthly climate normals (2016–2025) - bar colour and height show average temperature, the shaded area shows average monthly rain, with snow (water-equivalent) shown separately.
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Long-Term Trends
Combined Timeline – Massachusetts
Right axis: everything else standardized to standard deviations (σ) from its own average, since mm/hours/days aren't directly comparable to °C or to each other.
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Heatwave Days – Massachusetts
Warm Spell Duration Index (WSDI) - the WMO/ETCCDI heatwave measure: days in a 6+ day run above the local 90th-percentile temperature for that time of year.
Data: World Bank Climate Change Knowledge Portal (ERA5-derived). Refreshed roughly 1-2x/year, ~7-8 months behind present.
Year-on-Year Trends
The 4byo Climate Helix – Massachusetts
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Monthly Temperature – Massachusetts
Background lines show the last 40 years (plus the record year and its opposite, wherever they fall).
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Records – Massachusetts
NOAA National Centers for Environmental Information (frost: World Bank CCKP; snow: GPCC (DWD)) - Anomalies vs 1901-2000 mean
Shifting Seasons
Warm / cold seasonsKöppen Dfb · ContinentalHow spring and autumn have shifted in Massachusetts. Spring is defined as the date monthly temperatures first rise above the long-term annual mean (8.4°C, from 1950–1979); autumn is the date they fall back below it. Temperature swings 25.4°C peak-to-peak across the year - a classic four-seasons rhythm.
Baseline vs recent monthly temperature climatology. Biggest warming: Feb (+3.0°C).
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Emissions & Energy
Explore
Explore Climate Data
Data Sources
Data Sources for Massachusetts
Every figure on this page is sourced from official, openly published climate datasets. Anomalies are calculated against the 1961–1990 baseline (temperature) and 1991–2020 (rainfall, sunshine, frost) - see the Methodology & Sources page for the complete dataset list and update calendar.
Statewide monthly temperature and precipitation (nClimDiv).
Frost Days and Heatwave Days (Warm Spell Duration Index), ERA5-derived. World Bank Climate Change Knowledge Portal.
Monthly snow water-equivalent, Global Precipitation Climatology Centre (DWD).
FAQs
FAQs
How is the climate in Massachusetts changing?
Massachusetts is warming in line with the rest of the world. The page above shows the latest monthly temperature anomaly versus the 1961-1990 baseline, the long-term annual trend, and the region's rank in the historical record. The headline panel also shows the long-term trend rate per decade and the warmest and coolest years on file.
What is the climate like in Massachusetts?
Massachusetts has a continental climate (Köppen Dfa: Humid continental - hot summer), with distinct warm summers and cool-to-cold winters. July is typically the warmest month, averaging 22.7°C, while January is the coldest at -2.0°C. Annual precipitation averages around 1236mm, spread fairly evenly across the year.
Where does the climate data for Massachusetts come from?
Climate data for Massachusetts comes from NOAA Climate at a Glance (temperature and precipitation), refreshed every month, when the upstream temperature and rainfall data are refreshed.
What is the climate baseline used on this page?
Anomalies on this page are calculated against the 1961-1990 climatological baseline, which is the standard reference period used by the Met Office, NOAA, IPCC and most national climate services. Some panels also show the source-native 1901-2000 (NOAA) or 1991-2020 (WMO) baselines for verification. See Methodology & Sources for the full reference.
Which areas does the Massachusetts climate data cover?
The Massachusetts climate profile covers Boston, Worcester, Springfield, Cambridge and surrounding areas. Massachusetts climate data from NOAA Climate at a Glance
How often is the Massachusetts climate update refreshed?
The Massachusetts climate update is refreshed monthly, typically a few days after the previous month closes and the upstream provider (Met Office HadUK-Grid, NOAA Climate at a Glance, Copernicus ERA5 or the Global Carbon Project) publishes its update. See the Climate Rankings for cross-region comparisons.
What counts as a Heatwave Day on the Massachusetts climate page?
Heatwave Days use the Warm Spell Duration Index (WSDI) - the WMO/ETCCDI-standard heatwave measure: days that are part of a run of 6 or more consecutive days above the local 90th-percentile temperature for that calendar day. The 90th-percentile threshold varies by time of year (a hot day in January is judged differently to one in July) but is fixed to the 1961-1990 baseline for every year shown - it does not shift as the climate warms, which is why Heatwave Days trend upward over time.
Does the Massachusetts climate page include frost and snow data?
Yes. Frost Days (days with a minimum temperature below 0°C, World Bank CCKP) and snow water-equivalent (GPCC) are shown alongside temperature and precipitation, each measured against the 1961-1990 baseline where a like-for-like historical comparison is available.