Climate averages 1991–2020
Dorchester weather
in July.
A warm, moderately wet month: the warmest and the driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
July is a warm month in Dorchester: daytime highs average 27.2°C and nights cool to about 18.6°C. By daytime temperature it is the warmest month of the year.
Expect about 73 mm of rain on roughly 10 days, which makes July a moderately wet month (the driest month of the year). Daylight, from sunrise to sunset, lasts about 14 h 56 min on an average July day.
The nearest other city in this atlas is Boston (7 km away). In July its highs average 27.5°C, about as warm as Dorchester, with 73 mm of rain.
Among the 498 cities listed in the United States, Dorchester ranks joint 414th of 498 for the warmest July highs and joint 223rd of 498 for the driest July (rainfall, lowest first). The mean July high of those 498 cities is 30.3°C; Dorchester is 3.1°C cooler than that mean.
From July to August, average highs fall by 0.9°C to 26.3°C, and monthly rainfall rises from 73 mm to 85 mm.
The annual picture
July in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Dorchester climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 1.7°C-6.3°C | -6.3°C | 94 | 10.0 | 9.59 h |
| February | 3.0°C-5.5°C | -5.5°C | 84 | 8.9 | 10.511 h |
| March | 6.7°C-1.9°C | -1.9°C | 116 | 11.1 | 11.912 h |
| April | 13.0°C3.8°C | 3.8°C | 100 | 11.0 | 13.313 h |
| May | 18.5°C9.5°C | 9.5°C | 81 | 10.6 | 14.615 h |
| June | 23.8°C15.0°C | 15.0°C | 87 | 10.1 | 15.215 h |
| July, selected | 27.2°C18.6°C | 18.6°C | 73 | 9.6 | 14.915 h |
| August | 26.3°C18.1°C | 18.1°C | 85 | 9.1 | 13.914 h |
| September | 22.2°C14.4°C | 14.4°C | 88 | 8.1 | 12.513 h |
| October | 15.9°C8.5°C | 8.5°C | 108 | 9.8 | 11.111 h |
| November | 9.9°C2.8°C | 2.8°C | 95 | 9.6 | 9.810 h |
| December | 4.6°C-2.4°C | -2.4°C | 115 | 10.8 | 9.29 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
July in nearby cities
- Boston in JulyUnited States · 7 kmHigh 27.5°C · Low 18.4°C · 73 mm rain
- Quincy in JulyUnited States · 8 kmHigh 26.6°C · Low 18.8°C · 73 mm rain
- Newton in JulyUnited States · 12 kmHigh 27.7°C · Low 18.7°C · 77 mm rain
- Lynn in JulyUnited States · 21 kmHigh 25.2°C · Low 18.6°C · 74 mm rain
- Brockton in JulyUnited States · 24 kmHigh 27.1°C · Low 18.7°C · 77 mm rain
- Lowell in JulyUnited States · 42 kmHigh 27.8°C · Low 18.2°C · 82 mm rain
- Lawrence (Massachusetts), United States in JulyUnited States · 46 kmHigh 27.8°C · Low 18.4°C · 82 mm rain
- Pawtucket in JulyUnited States · 53 kmHigh 28.3°C · Low 19.0°C · 84 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Dorchester) is explained once on the Dorchester year overview and on the Sources, method and limits page.
Boston and Quincy lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.