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Chester climate
Typical historical weather for Chester, United States, averaged across 10 years of hourly climate data. Pick a date for a specific day.
Want today's actual conditions instead? See the current forecast for Chester. Planning a garden? See the gardening & growing season planner. Or browse the 365-day climate calendar.
Annual average
6.7°C
across all months
Warmest month
29.1°C
Jul average high
Coolest month
-12.4°C
Feb average low
Annual rainfall
356mm
total per year
Chester is typically hottest in July and coolest in February, a swing of about 41.5°C across the year. About 41% of annual rainfall falls in the three wettest months (May is typically wettest, January 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 | -1.7°C · record 4.5–12.3°C | -10.4°C · record -46–-16.6°C | 17mm | 5 | 75% | 4.3 m/s | 63% | 1.6 kWh/m² |
| Feb | -3°C · record 1.7–15.4°C | -12.4°C · record -39.2–-9.7°C | 25mm | 6 | 72% | 4.4 m/s | 66% | 2.7 kWh/m² |
| Mar | 4.7°C · record 5.7–20.7°C | -5.5°C · record -34.8–-8.9°C | 20mm | 5 | 70% | 4.2 m/s | 62% | 4.2 kWh/m² |
| Apr | 11.6°C · record 21.5–28.6°C | 0.4°C · record -19.3–-2.4°C | 36mm | 8 | 59% | 4.6 m/s | 61% | 5.5 kWh/m² |
| May | 18.5°C · record 26.9–33.9°C | 6.8°C · record -3.7–4.2°C | 57mm | 9 | 56% | 4.4 m/s | 56% | 6.4 kWh/m² |
| Jun | 23.4°C · record 30.8–38.9°C | 10.8°C · record 2.3–6.7°C | 53mm | 10 | 53% | 4.5 m/s | 48% | 7.1 kWh/m² |
| Jul | 29.1°C · record 35–40°C | 14.2°C · record 6.2–11.7°C | 21mm | 5 | 46% | 3.9 m/s | 31% | 7.4 kWh/m² |
| Aug | 27.7°C · record 33.6–40.2°C | 13.4°C · record 3.2–9.5°C | 27mm | 5 | 47% | 3.8 m/s | 39% | 6.2 kWh/m² |
| Sep | 21.8°C · record 30.2–37.6°C | 8.8°C · record -2.4–3.6°C | 26mm | 5 | 54% | 4 m/s | 44% | 4.5 kWh/m² |
| Oct | 12.5°C · record 21.1–29.7°C | 1.4°C · record -20.1–-2.3°C | 28mm | 6 | 63% | 4.4 m/s | 52% | 2.9 kWh/m² |
| Nov | 5°C · record 11.3–20.2°C | -4.5°C · record -24.8–-9.9°C | 24mm | 6 | 71% | 4.5 m/s | 60% | 1.8 kWh/m² |
| Dec | -0.7°C · record 5.6–17.1°C | -9.5°C · record -34.9–-11.5°C | 22mm | 7 | 72% | 4.3 m/s | 62% | 1.3 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 +1.06°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 -81.86mm per decade over the same period.
2025 (the most recent year on file) averaged 7.363774438100341°C, above the 9-year baseline of 6.72°C by 0.69 standard deviations.
Typical extremes per year
Rainy days
75.5 days
≥1.0mm rain
Heavy rain days
0.8 days
≥20mm rain
Extreme heat days
0.1 days
daily high ≥40°C
Frost days
151.6 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
40.2°C
10 August 2018
2018 was 1.94 SD below the 9-year average that year
Coldest day
-46°C
13 January 2024
2024 was 0.35 SD above the 9-year average that year
Wettest day
37.6mm
9 June 2023
2023 was 1.01 SD above the 9-year average that year
Windiest day
12.6m/s
7 May 2024
2024 was 0.35 SD above the 9-year average that year
See the detail: Chester on 9 June 2023.
Nearby cities
Shelby
55.3 km away
Conrad
78.9 km away
Fort Benton
85.4 km away
Havre
92.1 km away
Cut Bank
96 km away
Great Falls
112.7 km away
Want a side-by-side view instead? Compare Chester with another city.
Frequently asked questions about Chester's climate
What is the hottest month in Chester?
July is typically the warmest month in Chester, with an average high of 29.1°C. February is typically the coolest, averaging -12.4°C overnight.
How much does it rain in Chester?
Chester gets about 356mm of rain a year on average, with roughly 41% of it falling in the three wettest months (May is typically the wettest, January the driest).
How many extremely hot or cold days does Chester have?
On average, Chester sees about 0.1 day(s) a year at or above 40°C and about 151.6 day(s) at or below 0°C, based on 10 years of data.
Is Chester getting warmer?
Across the 10 years on file (2016–2025), the annual average temperature has moved by about +1.06°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 Chester?
The hottest day on file is 10 August 2018 at 40.2°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
- Chester — 48.500°, -111.000°, ERA5 grid cell center, 2.7 km from requested point
- Time zone
- America/Denver
- 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 (2026-07-18). Historical climate data for Chester, United States (48.50°N, 111.00°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Chester, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 18, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Chester, United States." PastClimate, derived from ERA5 (Copernicus Climate Change Service), July 18, 2026, www.pastclimate.com.
@misc{pastclimate,
author = {PastClimate},
title = {Historical climate data for Chester, United States},
year = {2026},
note = {Derived from ERA5 (Hersbach et al., 2023), Copernicus Climate Change Service. Accessed 2026-07-18},
url = {https://www.pastclimate.com/}
}Notice something wrong with this data? Report a data issue.