DeKalb, Illinois Climate
United States
Pop. 43,211 Elev. 270 m / 886 ft
TZ: America/Chicago (UTC-5) ·
Dry and warm, DeKalb sees July highs of 85°F (29°C) and cold January lows of 15°F (-9°C). Humidity pushes the summer feels-like temperature to 94°F (34°C), while wind chill can drive winter lows to 5°F (-15°C). Expect around 46 rainy days annually (32.6 in / 828 mm total), with snow on 5 days and 34 in (865 mm) of annual accumulation. The city averages 116 sunny days per year and around 33 thunderstorm days. Nearby lake water reaches 76°F (24°C) in summer.
| Temperature | 85°F (29°C) high | 15°F (-10°C) low |
| Feels like | 94°F (34°C) high | 5°F (-15°C) low |
| Rain | 46 days | 32.6 in (828 mm) /yr |
| Snow | 5 days | 34.0 in (865 mm) /yr |
| Sky | 116 sunny | 33 stormy |
| Wind | 2.6 mph (1.1 m/s) avg |
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Explore on the MapMonthly Climate Chart
Best months to visit: Apr, May, Sep, Oct
Sky & Air by Month
Cloud cover (%)
55
Jan 63
Feb 56
Mar 67
Apr 60
May 53
Jun 61
Jul 51
Aug 35
Sep 46
Oct 57
Nov 76
Dec Humidity (%)
60
Jan 67
Feb 58
Mar 59
Apr 61
May 64
Jun 73
Jul 74
Aug 67
Sep 67
Oct 66
Nov 76
Dec Weather Days by Month
Water Temperatures
Cities with Similar Climate
Find similar cities on the map →Nearby Cities
Nearby
Commercial airport 26 mi Chicago Rockford International Airport (RFD)
Ski resort 21 mi
National park 61 mi Historic Pullman Foundation Exhibit Hall
Hospital 3 mi Northwestern Medicine Kishwaukee Community Hospital
Hiking trail 22 mi Nature Loop
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Monthly Weather Data
↑ See chart| Month | Avg High | Avg Low | Rainfall | Snowfall | Sunny Days |
|---|---|---|---|---|---|
| January | 30°F -1°C | 15°F -10°C | 1.1 in 29 mm | 3.0 in77 mm | 13 |
| February | 34°F 1°C | 17°F -8°C | 0.1 in 3 mm | 7.8 in199 mm | 5 |
| March | 56°F 14°C | 34°F 1°C | 3.4 in 87 mm | 5.3 in134 mm | 10 |
| April | 61°F 16°C | 42°F 6°C | 3.4 in 87 mm | 0.0 in1 mm | 4 |
| May | 69°F 21°C | 50°F 10°C | 3.4 in 85 mm | — | 9 |
| June | 84°F 29°C | 64°F 18°C | 4.1 in 103 mm | — | 10 |
| July | 85°F 29°C | 69°F 20°C | 5.1 in 130 mm | — | 6 |
| August | 79°F 26°C | 62°F 17°C | 4.2 in 106 mm | — | 14 |
| September | 78°F 25°C | 56°F 13°C | 3.1 in 78 mm | — | 18 |
| October | 66°F 19°C | 48°F 9°C | 1.7 in 43 mm | — | 13 |
| November | 49°F 10°C | 35°F 1°C | 1.1 in 29 mm | 10.3 in261 mm | 10 |
| December | 33°F 1°C | 19°F -7°C | 1.9 in 48 mm | 7.6 in194 mm | 4 |
Weather Days by Month
↑ See chart| Month | Sunny Days | Storm Days |
|---|---|---|
| January | 13 | 1 |
| February | 5 | 0 |
| March | 10 | 4 |
| April | 4 | 2 |
| May | 9 | 3 |
| June | 10 | 4 |
| July | 6 | 7 |
| August | 14 | 6 |
| September | 18 | 4 |
| October | 13 | 1 |
| November | 10 | 0 |
| December | 4 | 1 |
Water Temperatures Data
↑ See chart| Month | Lake Avg High |
|---|---|
| January | 32°F 0°C |
| February | 32°F 0°C |
| March | 36°F 2°C |
| April | 46°F 8°C |
| May | 55°F 13°C |
| June | 67°F 19°C |
| July | 76°F 24°C |
| August | 73°F 23°C |
| September | 65°F 18°C |
| October | 59°F 15°C |
| November | 43°F 6°C |
| December | 32°F 0°C |