Climate Decatur - Illinois
| JanJa | FebFe | MarMa | AprAp | MayMa | JunJu | |
|---|---|---|---|---|---|---|
| Average high in ºF Av. high Hi | 36 | 41 | 53 | 66 | 76 | 85 |
| Average low in ºF Av. low Lo | 19 | 23 | 32 | 43 | 53 | 62 |
| Av. precipitation in inch Av. precip. Pre. | 2.14 | 2.00 | 2.59 | 3.67 | 4.79 | 4.50 |
| Av. snowfall in inch Snowfall Sn | 5 | 4 | 2 | 0 | 0 | 0 |
| JulJu | AugAu | SepSe | OctOc | NovNo | DecDe | |
|---|---|---|---|---|---|---|
| Average high in ºF Av. high Hi | 87 | 86 | 80 | 68 | 53 | 39 |
| Average low in ºF Av. low Lo | 66 | 64 | 56 | 45 | 34 | 23 |
| Av. precipitation in inch Av. precip. Pre. | 3.98 | 3.77 | 3.14 | 3.25 | 3.71 | 2.78 |
| Av. snowfall in inch Snowfall Sn | 0 | 0 | 0 | 0 | 0 | 5 |
What is the average weather in Decatur, Illinois?
Decatur experiences a humid continental climate, marked by very strong seasonal temperature contrasts. Summers are hot, while winters are cold and bring regular snowfall. The area is fairly wet overall, with precipitation spread relatively evenly throughout the year, though summer tends to be wetter.
Decatur Climate Graph - Illinois Climate Chart
Daily normals Decatur - Illinois - January
Day | High ºF | Low ºF | Prec/mo inch | Prec/yr inch | Snow/mo inch | Snow/yr inch |
|---|---|---|---|---|---|---|
| 1 Jan | 34.7 | 21.4 | 0.10 | 0.10 | 0.20 | 0.20 |
| 2 Jan | 34.6 | 21.2 | 0.19 | 0.19 | 0.40 | 0.40 |
| 3 Jan | 34.4 | 21.0 | 0.28 | 0.28 | 0.60 | 0.60 |
| 4 Jan | 34.3 | 20.8 | 0.38 | 0.38 | 0.80 | 0.80 |
| 5 Jan | 34.2 | 20.6 | 0.47 | 0.47 | 1.00 | 1.00 |
| 6 Jan | 34.0 | 20.4 | 0.56 | 0.56 | 1.20 | 1.20 |
| 7 Jan | 33.9 | 20.3 | 0.65 | 0.65 | 1.40 | 1.40 |
| 8 Jan | 33.9 | 20.1 | 0.74 | 0.74 | 1.60 | 1.60 |
| 9 Jan | 33.8 | 20.0 | 0.82 | 0.82 | 1.80 | 1.80 |
| 10 Jan | 33.7 | 19.8 | 0.91 | 0.91 | 2.00 | 2.00 |
| 11 Jan | 33.6 | 19.7 | 0.99 | 0.99 | 2.20 | 2.20 |
| 12 Jan | 33.6 | 19.6 | 1.06 | 1.06 | 2.40 | 2.40 |
| 13 Jan | 33.6 | 19.5 | 1.14 | 1.14 | 2.60 | 2.60 |
| 14 Jan | 33.5 | 19.4 | 1.21 | 1.21 | 2.80 | 2.80 |
| 15 Jan | 33.5 | 19.3 | 1.29 | 1.29 | 3.10 | 3.10 |
| 16 Jan | 33.5 | 19.2 | 1.37 | 1.37 | 3.30 | 3.30 |
| 17 Jan | 33.5 | 19.1 | 1.45 | 1.45 | 3.50 | 3.50 |
| 18 Jan | 33.6 | 19.1 | 1.53 | 1.53 | 3.70 | 3.70 |
| 19 Jan | 33.6 | 19.1 | 1.60 | 1.60 | 3.90 | 3.90 |
| 20 Jan | 33.6 | 19.0 | 1.67 | 1.67 | 4.10 | 4.10 |
| 21 Jan | 33.7 | 19.0 | 1.74 | 1.74 | 4.20 | 4.20 |
| 22 Jan | 33.8 | 19.0 | 1.82 | 1.82 | 4.40 | 4.40 |
| 23 Jan | 33.9 | 19.1 | 1.89 | 1.89 | 4.60 | 4.60 |
| 24 Jan | 34.0 | 19.1 | 1.96 | 1.96 | 4.80 | 4.80 |
| 25 Jan | 34.1 | 19.2 | 2.03 | 2.03 | 5.00 | 5.00 |
| 26 Jan | 34.2 | 19.2 | 2.09 | 2.09 | 5.20 | 5.20 |
| 27 Jan | 34.3 | 19.3 | 2.16 | 2.16 | 5.30 | 5.30 |
| 28 Jan | 34.5 | 19.4 | 2.22 | 2.22 | 5.50 | 5.50 |
| 29 Jan | 34.6 | 19.5 | 2.28 | 2.28 | 5.60 | 5.60 |
| 30 Jan | 34.8 | 19.7 | 2.34 | 2.34 | 5.80 | 5.80 |
| 31 Jan | 35.0 | 19.8 | 2.40 | 2.40 | 5.90 | 5.90 |
Weather history Decatur - August 2026
| Day | High ºF | Low ºF | Precip. inch | Snow inch | Snow d. inch |
|---|---|---|---|---|---|
| 01 Aug | 71.1 | 64.9 | 0.44 | - | - |
| 02 Aug | 77.0 | 63.0 | 0.00 | 0.00 | 0.0 |
| 03 Aug | 71.1 | 61.0 | 0.00 | 0.00 | 0.0 |
| 04 Aug | 82.0 | 64.0 | 0.00 | 0.00 | 0.0 |
| 05 Aug | - | - | - | - | - |
| 06 Aug | 75.9 | - | 0.09 | 0.00 | 0.0 |
| 07 Aug | 78.1 | 64.0 | 0.00 | 0.00 | 0.0 |
| 08 Aug | 84.9 | - | 0.00 | - | - |
| 09 Aug | 84.0 | 69.1 | 0.00 | - | - |
| 10 Aug | 89.1 | 75.0 | 0.00 | - | - |
| 11 Aug | - | - | - | - | - |
| 12 Aug | - | - | - | - | - |
| 13 Aug | - | - | - | - | - |
| 14 Aug | - | - | - | - | - |
| 15 Aug | - | - | - | - | - |
| 16 Aug | - | - | - | - | - |
| 17 Aug | - | - | - | - | - |
| 18 Aug | - | - | - | - | - |
| 19 Aug | - | - | - | - | - |
| 20 Aug | - | - | - | - | - |
| 21 Aug | - | - | - | - | - |
| 22 Aug | - | - | - | - | - |
| 23 Aug | - | - | - | - | - |
| 24 Aug | - | - | - | - | - |
| 25 Aug | - | - | - | - | - |
| 26 Aug | - | - | - | - | - |
| 27 Aug | - | - | - | - | - |
| 28 Aug | - | - | - | - | - |
| 29 Aug | - | - | - | - | - |
| 30 Aug | - | - | - | - | - |
| 31 Aug | - | - | - | - | - |
Past weather Decatur
| Aug 26 | Normal | ||
|---|---|---|---|
| Average high temperature Av. high temp. | 79.2 ºF | 36 ºF | |
| Average low temperature Av. low temp. | 65.9 ºF | 19 ºF | |
| Total precipitation Total precip. | 0.53 inch | 2.14 inch | |
| Total snowfall Total snowfall | - inch | 5 inch | |
| Highest max temperature Highest max temp. | 89.1 ºF | - | |
| Lowest max temperature Lowest max temp. | 71.1 ºF | - | |
| Highest min temperature Highest min temp. | 75.0 ºF | - | |
| Lowest min temperature Lowest min temp. | 61.0 ºF | - | |
Past weather August 2026 incomplete - Missing data
Geo Decatur - Illinois
| Country | United States | |
|---|---|---|
| State | Illinois | |
| County | - | |
| City | Decatur | |
| Zip Code | 62521 | |
| Longitude | -88.95 dec. degr. | |
| Latitude | 39.84 dec. degr. | |
| Altitude - Elevation | 676ft | |
| ICAO | - | |
| IATA | - |
Date and Time Decatur - Illinois
| Local Time | 05:36 PM | |
|---|---|---|
| Sunrise | 06:04 AM | |
| Sunset | 07:56 PM | |
| Day/Night | Day | |
| Timezone | Central Daylight Time | |
| Timezone DB | America - Chicago |
Map of Decatur - Illinois
USGS National Map — Open interactive map
Decatur weather averages
| Annual high temperature | 64ºF |
| Annual low temperature | 43ºF |
| Average annual precip. | 40.32 inch |
| Av. annual snowfall | 16 inch |
Station Data
Monthly averages Decatur
Longitude: -88.9548, Latitude: 39.8403
Average weather Decatur, IL - 62521
Monthly: 1991-2020 normals
History: 2008-2026
Abbreviations
Average precipitation in : Av. precipitation in
Jan: January, Feb: February, ...Jan: January, Feb: February, ...Ja: January, Fe: February, ...