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Charlestown climate
Typical historical weather for Charlestown, United States, averaged across 10 years of hourly climate data. Pick a date for a specific day.
Data last updated: 31 December 2025
Want today's actual conditions instead? See the current forecast for Charlestown. Planning a garden? See the gardening & growing season planner. Or browse the 365-day climate calendar.
Annual average
10.9°C
across all months
Warmest month
26.3°C
Jul average high
Coolest month
-3.7°C
Jan average low
Annual rainfall
1167mm
total per year
Charlestown is typically hottest in July and coolest in January, a swing of about 30°C across the year. About 31% of annual rainfall falls in the three wettest months (December is typically wettest, August driest).
Monthly averages
Average daily high/low temperature (band) and monthly rainfall (bars).
| Month | Avg high | Avg low | Rainfall | Wet days | Humidity | Wind | Cloud | Solar |
|---|---|---|---|---|---|---|---|---|
| Jan | 2.9°C · record 8.3°C–19°C | -3.7°C · record -19.5°C–-4.1°C | 101mm | 10 | 66% | 4.8 m/s | 58% | 1.9 kWh/m² |
| Feb | 4.5°C · record 9.6°C–18.9°C | -3.1°C · record -22.8°C–-8.7°C | 90mm | 10 | 66% | 4.6 m/s | 59% | 2.8 kWh/m² |
| Mar | 7.5°C · record 12.7°C–19.9°C | 0.3°C · record -13.9°C–-2.9°C | 112mm | 12 | 63% | 4.8 m/s | 59% | 4 kWh/m² |
| Apr | 12.1°C · record 14.8°C–26°C | 5°C · record -4.2°C–0.8°C | 117mm | 12 | 66% | 4.3 m/s | 63% | 4.8 kWh/m² |
| May | 17.6°C · record 23°C–30.3°C | 10.4°C · record 2.6°C–6.5°C | 89mm | 11 | 70% | 3.8 m/s | 65% | 5.6 kWh/m² |
| Jun | 22.8°C · record 26.6°C–34°C | 15.4°C · record 7.6°C–11.7°C | 77mm | 11 | 73% | 3.5 m/s | 59% | 6.1 kWh/m² |
| Jul | 26.3°C · record 29.6°C–33.2°C | 19.3°C · record 13.7°C–16.4°C | 94mm | 11 | 75% | 3.3 m/s | 57% | 5.9 kWh/m² |
| Aug | 25.7°C · record 27.7°C–33.8°C | 18.7°C · record 12.3°C–16.5°C | 73mm | 10 | 74% | 3.2 m/s | 55% | 5.4 kWh/m² |
| Sep | 22°C · record 25.8°C–32°C | 15.2°C · record 7.2°C–11.7°C | 87mm | 10 | 76% | 3.5 m/s | 56% | 4.1 kWh/m² |
| Oct | 16.8°C · record 22.9°C–26.8°C | 9.7°C · record -2.5°C–5.3°C | 116mm | 10 | 75% | 4.1 m/s | 54% | 2.9 kWh/m² |
| Nov | 10.4°C · record 15.7°C–24.4°C | 2.9°C · record -10.6°C–-0.2°C | 87mm | 9 | 67% | 4.5 m/s | 48% | 2.1 kWh/m² |
| Dec | 4.8°C · record 12.5°C–16.4°C | -1.7°C · record -17.8°C–-5.6°C | 123mm | 11 | 69% | 4.6 m/s | 56% | 1.6 kWh/m² |
"Avg high"/"Avg low" is the mean daily high/low for that month, averaged across every year on file. The "record" figure alongside it is a different statistic — the single hottest (or coldest) hour ever recorded during that month across all years — so it can sit above or below the average and does not describe the average's year-to-year spread. A "wet day" is any day with at least 1.0mm of rain.
Year to year
Annual average temperature, 2016–2025.
Across these 10 years, the annual average has moved by about +0.2°C per decade. That’s a short window for a reliable long-term climate trend — treat it as indicative, not definitive.
Annual rainfall has moved by about -31.69mm per decade over the same period.
2025 (the most recent year on file) averaged 10.3°C, below the 9-year baseline of 11°C by 1.99 standard deviations.
Typical extremes per year
Rainy days
126.5 days
≥1.0mm rain
Heavy rain days
13.6 days
≥20mm rain
Extreme heat days
0 days
daily high ≥40°C
Frost days
84.4 days
daily low ≤0°C
Averaged across 10 years on file. Thresholds match PastClimate's data pipeline definitions — see data & sources.
Records on file
Ranked across 10 years of data currently on file (2016–2025).
Hottest day
34°C
24 June 2025
2025 was 1.99 SD below the 9-year average that year
Coldest day
-22.8°C
14 February 2016
2016 was 0.45 SD above the 9-year average that year
Wettest day
68.1mm
5 December 2020
2020 was 0.88 SD above the 9-year average that year
Windiest day
11.4m/s
2 March 2018
2018 was 0.75 SD below the 9-year average that year
See the detail: Charlestown on 5 December 2020.
Nearby cities
Frequently asked questions about Charlestown's climate
What is the hottest month in Charlestown?
July is typically the warmest month in Charlestown, with an average high of 26.3°C. January is typically the coolest, averaging -3.7°C overnight.
How much does it rain in Charlestown?
Charlestown gets about 1167mm of rain a year on average, with roughly 31% of it falling in the three wettest months (December is typically the wettest, August the driest).
How many extremely hot or cold days does Charlestown have?
On average, Charlestown sees about 0 day(s) a year at or above 40°C and about 84.4 day(s) at or below 0°C, based on 10 years of data.
Is Charlestown getting warmer?
Across the 10 years on file (2016–2025), the annual average temperature has moved by about +0.16°C per decade. That's a short window for a reliable long-term climate trend — treat it as indicative, not definitive.
What is the hottest day on record for Charlestown?
The hottest day on file is 24 June 2025 at 34°C, out of 10 year(s) searched.
Data & provenance
↓ Download monthly CSVData source & coverage — ERA5 reanalysis, 2016–2025 (10 years)details
- Source
- ERA5 reanalysis, accessed via the Copernicus Climate Change Service (C3S) Climate Data Store
- Data type
- Reanalysis — a physically consistent reconstruction combining a forecast model with historical observations, not a live station reading or a forecast
- Coverage
- 2016–2025 (10 years) for United States
- Location
- Charlestown — 42.500°, -71.000°, ERA5 grid cell center, 14.5 km from requested point
- Time zone
- America/New_York
- What's shown here
- Monthly and annual averages, and dated extreme-value records, derived from an hourly base record.
- Spatial resolution
- 0.25° (~25 km) distributed grid — ERA5's native model resolution is finer; this is the publicly distributed regridded product
- Version / refreshed
- Methodology v2026.07 · data last refreshed December 31, 2025
- Limitations
- A model reconstruction, not a station observation — hyper-local extremes (a single storm cell, an urban heat pocket) can differ from a nearby gauge. See the full methodology.
- Attribution
- Generated using Copernicus Climate Change Service information
Cite this data
PastClimate (2026-07-20). Historical climate data for Charlestown, United States (42.50°N, 71.00°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Charlestown, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 20, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Charlestown, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 20, 2026, www.pastclimate.com.
@misc{pastclimate,
author = {PastClimate},
title = {Historical climate data for Charlestown, United States},
year = {2026},
note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-20},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.