Acton, United States experiences average highs of 15°C (59°F) and lows of 7°C (45°F) throughout the year. Rainfall is moderate, averaging about 10 rainy days per month. Average highs have cooled by 0.9°C (1.6°F) across the available records.
Acton, United States Weather & Climate 2026
Monthly climate averages for Acton, United States. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Dec 
Wetter season: Apr–Aug At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
5.2/10
Best: June, July, August, September
UV Index
5
Low
Temperature 15°C / 7°C
Feels Like 14°C / 4°C
Rainy Days 10
Rainfall 92 mm
Sunshine 8 h
Humidity 70%
Wind Speed 16 km/h
Dew Point 6°C
Snow Days 5 days
Frost Days 18 days
Hottest Month
29°C
July
Avg Low19°C
Rain12days
Coldest Month
-5°C
January
Avg High2°C
Rain9days
Driest Month
8days
September
Avg High23°C
Avg Low15°C
Windiest Month
19 km/h
March (Gusts 45)
Worst Time to Visit
Consider avoiding January, February, March, December due to very cold temperatures.
Sun Position
Sunrise 05:09
Daylight 15.3h
Sunset 20:26
Live conditions—
Acton on the map · live conditions
Acton, United States
- Continent
- Americas
- Country
- United States
- City
- Acton
- Population
- 20.9K
- Elevation
- 81 m
- Coordinates
- 42.49°, -71.43°
Seasonal Breakdown
Spring
Mar–May
Avg High 14°C
Avg Low 4°C
Rain 11 days/mo
Summer
Jun–Aug
Avg High 27°C
Avg Low 18°C
Rain 11 days/mo
3/3 best months
Autumn
Sep–Nov
Avg High 17°C
Avg Low 9°C
Rain 9 days/mo
1/3 best months
Winter
Dec–Feb
Avg High 4°C
Avg Low -4°C
Rain 9 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 2°C / -5°C . Feb: 4°C / -5°C . Mar: 8°C / -1°C . Apr: 14°C / 4°C . May: 20°C / 10°C . Jun: 25°C / 15°C . Jul: 29°C / 19°C . Aug: 28°C / 18°C . Sep: 23°C / 15°C . Oct: 17°C / 9°C . Nov: 10°C / 2°C . Dec: 4°C / -3°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 87 mm. Feb: 79 mm. Mar: 98 mm. Apr: 103 mm. May: 93 mm. Jun: 78 mm. Jul: 102 mm. Aug: 85 mm. Sep: 85 mm. Oct: 102 mm. Nov: 78 mm. Dec: 118 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 67%. Feb: 68%. Mar: 66%. Apr: 67%. May: 71%. Jun: 71%. Jul: 72%. Aug: 71%. Sep: 74%. Oct: 75%. Nov: 71%. Dec: 71%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 18 km/h . Feb: 18 km/h . Mar: 19 km/h . Apr: 18 km/h . May: 16 km/h . Jun: 15 km/h . Jul: 14 km/h . Aug: 14 km/h . Sep: 14 km/h . Oct: 16 km/h . Nov: 18 km/h . Dec: 17 km/h .
Sunshine
Sunshine
Sunshine: Jan: 6h. Feb: 7h. Mar: 8h. Apr: 8h. May: 10h. Jun: 11h. Jul: 11h. Aug: 11h. Sep: 9h. Oct: 7h. Nov: 7h. Dec: 6h.
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 2. Feb: UV 3. Mar: UV 4. Apr: UV 5. May: UV 6. Jun: UV 7. Jul: UV 7. Aug: UV 6. Sep: UV 5. Oct: UV 4. Nov: UV 3. Dec: UV 2.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy Oppressive
Snow Days
Snow DaysSnowfall
Snow Days: Jan: 9 days. Feb: 8 days. Mar: 5 days. Apr: 2 days. May: 0 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 0 days. Nov: 1 days. Dec: 6 days.
Climate Trends
Average highs have cooled by 0.9°C (1.6°F) across the available records. Average rainfall is trending wetter by about 18 mm.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 29°C | Jul · 29°C |
| Coldest month | Jan 2025 · -7°C | Jan · -5°C |
| Wettest month | May 2025 · 215 mm | Dec · 118 mm |
| Windiest month | Jan 2025 · 21 km/h | Mar · 19 km/h |
Month-by-Month Weather Table
January
Poor 
February
Poor March
Poor April
Fair May
Good June best
Excellent July best
Excellent August best
Excellent September best
Excellent October
Good November
Poor December
Poor | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 2°C / -5°C | -2°C / -10°C | 9days (87 mm) Wet | 5.9h Fair | 67% Muggy | 2.2 Moderate | Poor | View Details |
| February | 4°C / -5°C | 0°C / -9°C | 9days (79 mm) Wet | 6.8h Fair | 68% Muggy | 3.3 Moderate | Poor | View Details |
| March | 8°C / -1°C | 4°C / -6°C | 10days (98 mm) Wet | 7.8h Good | 66% Muggy | 4.2 Moderate | Poor | View Details |
| April | 14°C / 4°C | 11°C / 1°C | 12days (103 mm) Wet | 8.4h Good | 67% Muggy | 5.2 High | Fair | View Details |
| May | 20°C / 10°C | 19°C / 8°C | 11days (93 mm) Wet | 9.5h Good | 71% Muggy | 6.1 High | Good | View Details |
| June best | 25°C / 15°C | 26°C / 15°C | 11days (78 mm) Wet | 10.8h Excellent | 71% Muggy | 6.7 High | Excellent | View Details |
| July best | 29°C / 19°C | 31°C / 20°C | 12days (102 mm) Wet | 11.1h Excellent | 72% Muggy | 6.9 High | Excellent | View Details |
| August best | 28°C / 18°C | 29°C / 19°C | 11days (85 mm) Wet | 10.6h Excellent | 71% Muggy | 6.4 High | Excellent | View Details |
| September best | 23°C / 15°C | 23°C / 14°C | 8days (85 mm) Wet | 8.5h Good | 74% Muggy | 5.1 High | Excellent | View Details |
| October | 17°C / 9°C | 16°C / 7°C | 10days (102 mm) Wet | 6.9h Fair | 75% Muggy | 3.7 Moderate | Good | View Details |
| November | 10°C / 2°C | 7°C / -2°C | 9days (78 mm) Wet | 6.5h Fair | 71% Muggy | 2.6 Moderate | Poor | View Details |
| December | 4°C / -3°C | 0°C / -7°C | 10days (118 mm) Wet | 5.5h Fair | 71% Muggy | 1.9 Low | Poor | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Acton are June, July, August, September, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Acton, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Acton is July, with average daytime highs of 29°C (83°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Acton is January, with average overnight lows of -5°C (23°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Acton is December, averaging 118mm of precipitation across 10 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Acton runs through April, July, May, June, with the heaviest rainfall in April. Based on 10-year averages for Acton.
Acton receives approximately 98 sunshine hours per year. The sunniest month is July with around 11 hours. Based on climate data for Acton.
The least favorable months to visit Acton are January, February, March, December, primarily due to very cold temperatures. For the best conditions, consider June, July, August, September instead.
The annual average UV index in Acton is 5, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Acton is 70%, classified as moderate. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes, Acton receives snow. Months with snowfall average 5 snow days and 17 cm (7 in) of accumulation, with about 18 frost days during winter.
Average wind speeds in Acton are 16 km/h (10 mph). The windiest month is March with peak winds reaching 19 km/h (12 mph) (gusts up to 45 km/h / 28 mph).
Acton averages 4 clear-sky days per month with overall cloud cover around 58%. The clearest skies occur in November.
The annual average dew point in Acton is 6°C (43°F), which feels dry and comfortable. Outdoor activities are comfortable year-round from a humidity standpoint.
Acton has a Humid Subtropical climate, classified as Cfa under the Köppen system. Temperate climates have mild winters and warm summers, with rainfall spread across the year and four distinct seasons.
The 'feels like' temperature in Acton ranges from 4°C (39°F) to 14°C (57°F) on average. Wind chill makes winters feel noticeably colder than the actual temperature — layered clothing is recommended.
Yes, June is a great time to visit Acton. It earns a climate score of 8.5/10 with Excellent.
For June in Acton, pack Umbrella, Waterproof jacket, Breathable clothing, Sunscreen (SPF 30+), Sun hat. With average highs of 25°C (77°F) and 11 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
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