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Decatur climate
Typical historical weather for Decatur, United States, averaged across 10 years of hourly climate data. Pick a date for a specific day.
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Annual average
17.4°C
across all months
Warmest month
31.5°C
Jul average high
Coolest month
2.2°C
Jan average low
Annual rainfall
1319mm
total per year
Decatur is typically hottest in July and coolest in January, a swing of about 29.3°C across the year. About 29% of annual rainfall falls in the three wettest months (March is typically wettest, October 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 | 12°C · record 19.1–24.8°C | 2.2°C · record -10.6–-2.7°C | 125mm | 10 | 67% | 3.6 m/s | 55% | 2.7 kWh/m² |
| Feb | 16.2°C · record 22.6–27°C | 5.7°C · record -6.9–-1.6°C | 124mm | 12 | 69% | 3.6 m/s | 61% | 3.2 kWh/m² |
| Mar | 19.2°C · record 24.3–29.1°C | 8.3°C · record -5.4–0.9°C | 131mm | 12 | 63% | 3.5 m/s | 58% | 4.5 kWh/m² |
| Apr | 22.7°C · record 27.3–30.1°C | 11.4°C · record 0.4–4.5°C | 105mm | 9 | 65% | 3.3 m/s | 51% | 5.8 kWh/m² |
| May | 26.4°C · record 29.8–34.3°C | 16.6°C · record 4.6–12.2°C | 101mm | 12 | 70% | 2.8 m/s | 59% | 5.9 kWh/m² |
| Jun | 29.9°C · record 30.9–36.6°C | 20.6°C · record 13.6–16.8°C | 109mm | 14 | 71% | 2.4 m/s | 61% | 6.2 kWh/m² |
| Jul | 31.5°C · record 33–36.8°C | 22.6°C · record 16.1–21.7°C | 122mm | 17 | 74% | 2 m/s | 62% | 6 kWh/m² |
| Aug | 30.4°C · record 32.8–35.6°C | 21.8°C · record 14.3–21.1°C | 130mm | 16 | 77% | 2.1 m/s | 60% | 5.4 kWh/m² |
| Sep | 28.7°C · record 30.3–35.7°C | 18.9°C · record 9.2–19.7°C | 95mm | 8 | 72% | 2.5 m/s | 47% | 4.9 kWh/m² |
| Oct | 23.9°C · record 27.9–36.5°C | 12.7°C · record 0–6.3°C | 77mm | 6 | 71% | 3 m/s | 44% | 4 kWh/m² |
| Nov | 18.1°C · record 21.7–27.7°C | 6.9°C · record -5–1.9°C | 79mm | 8 | 69% | 3.2 m/s | 48% | 3 kWh/m² |
| Dec | 13.8°C · record 19.7–24.6°C | 4.1°C · record -13.7–-2.1°C | 121mm | 11 | 72% | 3.4 m/s | 61% | 2.2 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 -0.63°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 -5.23mm per decade over the same period.
2025 (the most recent year on file) averaged 17.171405238321405°C, below the 9-year baseline of 17.47°C by 0.8 standard deviations.
Typical extremes per year
Rainy days
134.1 days
≥1.0mm rain
Heavy rain days
17 days
≥20mm rain
Extreme heat days
0 days
daily high ≥40°C
Frost days
30.6 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
36.8°C
29 July 2025
2025 was 0.8 SD below the 9-year average that year
Coldest day
-13.7°C
24 December 2022
2022 was 1.48 SD below the 9-year average that year
Wettest day
98.5mm
17 September 2020
2020 was 0.18 SD below the 9-year average that year
Windiest day
9.9m/s
11 September 2017
2017 was 0.75 SD above the 9-year average that year
See the detail: Decatur on 17 September 2020.
Nearby cities
Brookhaven
Same ERA5 grid cell
Stonecrest
Same ERA5 grid cell
Redan
Same ERA5 grid cell
Tucker
Same ERA5 grid cell
Candler-McAfee
Same ERA5 grid cell
North Druid Hills
Same ERA5 grid cell
Want a side-by-side view instead? Compare Decatur with another city.
Frequently asked questions about Decatur's climate
What is the hottest month in Decatur?
July is typically the warmest month in Decatur, with an average high of 31.5°C. January is typically the coolest, averaging 2.2°C overnight.
How much does it rain in Decatur?
Decatur gets about 1319mm of rain a year on average, with roughly 29% of it falling in the three wettest months (March is typically the wettest, October the driest).
How many extremely hot or cold days does Decatur have?
On average, Decatur sees about 0 day(s) a year at or above 40°C and about 30.6 day(s) at or below 0°C, based on 10 years of data.
Is Decatur getting warmer?
Across the 10 years on file (2016–2025), the annual average temperature has moved by about -0.63°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 Decatur?
The hottest day on file is 29 July 2025 at 36.8°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
- Decatur — 33.750°, -84.250°, ERA5 grid cell center, 5.1 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 (2026-07-18). Historical climate data for Decatur, United States (33.75°N, 84.25°W), derived from ERA5 (Hersbach et al., 2023, Copernicus Climate Change Service). Retrieved from https://www.pastclimate.com/
PastClimate. (2026). Historical climate data for Decatur, United States [Data set]. Derived from ERA5 (Copernicus Climate Change Service). Retrieved July 18, 2026, from https://www.pastclimate.com/
"Historical Climate Data for Decatur, 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 Decatur, 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.