Rockford vs Decatur, Illinois Climate
88%matchOn climate, Decatur is a 88% match for Rockford. Compared with Rockford, Decatur has 6°F (3°C) milder winter nights and 4°F (2°C) hotter summer days.
Rockford gets 37 in (941 mm) of rain a year and Decatur 41 in (1034 mm). July is the warmest month in both, with highs of 84°F (29°C) in Rockford and 88°F (31°C) in Decatur.
Climate fingerprints: ring color = average temperature, thickness = rain. January at the top.
Month by month
Highs and lows (°F)
RockfordDecatursolid = high, dashed = low
Rain (in per month)
RockfordDecatur
Monthly averages
| Month | High | Low | Rain | |||
|---|---|---|---|---|---|---|
| Rockford | Decatur | Rockford | Decatur | Rockford | Decatur | |
| Jan | 29°F(-1°C) | 37°F(3°C) | 13°F(-10°C) | 20°F(-7°C) | 1.5 in(37 mm) | 2.2 in(55 mm) |
| Feb | 34°F(1°C) | 41°F(5°C) | 17°F(-8°C) | 23°F(-5°C) | 1.4 in(35 mm) | 2.0 in(51 mm) |
| Mar | 46°F(8°C) | 53°F(12°C) | 27°F(-3°C) | 33°F(1°C) | 2.2 in(57 mm) | 3.0 in(75 mm) |
| Apr | 60°F(15°C) | 65°F(19°C) | 37°F(3°C) | 43°F(6°C) | 3.9 in(100 mm) | 4.1 in(105 mm) |
| May | 72°F(22°C) | 76°F(25°C) | 49°F(9°C) | 53°F(12°C) | 4.2 in(106 mm) | 4.9 in(125 mm) |
| Jun | 81°F(27°C) | 85°F(29°C) | 58°F(15°C) | 62°F(17°C) | 4.9 in(124 mm) | 4.6 in(118 mm) |
| Jul | 84°F(29°C) | 88°F(31°C) | 63°F(17°C) | 66°F(19°C) | 3.9 in(98 mm) | 4.3 in(110 mm) |
| Aug | 82°F(28°C) | 87°F(30°C) | 61°F(16°C) | 64°F(18°C) | 3.8 in(97 mm) | 3.4 in(86 mm) |
| Sep | 76°F(24°C) | 81°F(27°C) | 53°F(11°C) | 56°F(13°C) | 4.1 in(104 mm) | 3.3 in(83 mm) |
| Oct | 63°F(17°C) | 68°F(20°C) | 41°F(5°C) | 45°F(7°C) | 2.8 in(72 mm) | 3.0 in(77 mm) |
| Nov | 47°F(8°C) | 53°F(12°C) | 30°F(-1°C) | 34°F(1°C) | 2.4 in(60 mm) | 3.1 in(80 mm) |
| Dec | 34°F(1°C) | 41°F(5°C) | 19°F(-7°C) | 25°F(-4°C) | 2.0 in(51 mm) | 2.7 in(69 mm) |
1991–2020 averages, by calendar month.