Rockford climate
Rockford (Illinois, United States) has a hot-summer humid continental climate (Köppen Dfa). The average temperature over the year is 9 °C48 °F, and about 967 mm38 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Rockford climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin | Frost days |
|---|---|---|---|---|---|
| Jan | −228 | −1112 | −720 | 391.5 | 30 |
| Feb | 032 | −1014 | −523 | 431.7 | 27 |
| Mar | 745 | −326 | 235 | 602.4 | 24 |
| Apr | 1559 | 236 | 947 | 933.7 | 10 |
| May | 2170 | 948 | 1559 | 1084.3 | 1 |
| Jun | 2679 | 1559 | 2169 | 1295.1 | 0 |
| Jul | 2883 | 1864 | 2373 | 1044.1 | 0 |
| Aug | 2781 | 1762 | 2272 | 1074.2 | 0 |
| Sep | 2475 | 1253 | 1864 | 933.7 | 0 |
| Oct | 1660 | 540 | 1050 | 803.2 | 6 |
| Nov | 846 | −229 | 338 | 562.2 | 20 |
| Dec | 033 | −818 | −425 | 542.1 | 29 |
| Year | 2883 | −1112 | 948 | 96738 | 147 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total. Frost days are for the whole grid cell.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 88% | 67% | 1.8 | 9:25 |
| Feb | 85% | 64% | 2.8 | 10:30 |
| Mar | 80% | 63% | 3.7 | 11:49 |
| Apr | 76% | 62% | 4.7 | 13:19 |
| May | 77% | 63% | 5.5 | 14:34 |
| Jun | 77% | 56% | 6.2 | 15:15 |
| Jul | 76% | 48% | 6.3 | 14:58 |
| Aug | 75% | 49% | 5.5 | 13:53 |
| Sep | 76% | 47% | 4.4 | 12:25 |
| Oct | 77% | 59% | 2.9 | 10:59 |
| Nov | 81% | 64% | 1.9 | 9:43 |
| Dec | 88% | 70% | 1.4 | 9:06 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Rockford is like
The warmest month is July, with an average high of 28 °C83 °F and a low of 18 °C64 °F. The coldest is January, when highs average −2 °C28 °F and lows −11 °C12 °F. Seasons are strongly marked: the warmest month is on average 29.8 °C53.7 °F warmer than the coldest.
Annual precipitation is moderate at about 967 mm38 in. The wettest three-month stretch is May–July, which brings 35% of the annual total. The wettest month is June (129 mm5.1 in), the driest is January (39 mm1.5 in).
Relative humidity ranges from 75% in August to 88% in December. The clearest skies (lowest average cloud amount, 47%) are typical of September. Average wind speed near the ground ranges from 8 km/h (5 mph) in August to 14 km/h (9 mph) in February. Daylight lasts from about 9.1 hours in December to 15.3 hours in June.
A lasting snow cover is typical in December–March, when the average snow depth in the reanalysis exceeds 10 cm (deepest in January, about 16 cm).
Best time to visit Rockford
Based on these averages, the most comfortable months for sightseeing and outdoor activities are May and July–September: average highs of 21 °C70 °F to 28 °C83 °F with 93 mm3.7 in to 108 mm4.3 in of precipitation per month.
The most challenging month is January, which is cold, with average highs of −2 °C28 °F.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Rockford
- Winter (December–February) — highs −228 to 0 °C33 °F, lows −1112 to −8 °C18 °F, about 45 mm1.8 in of precipitation a month. Pack a winter coat, hat, gloves and warm, non-slip boots and shoes with good grip, as frost is common.
- Spring (March–May) — highs 745 to 21 °C70 °F, lows −326 to 9 °C48 °F, about 87 mm3.4 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket and an extra layer for the cooler mornings and evenings.
- Summer (June–August) — highs 2679 to 28 °C83 °F, lows 1559 to 18 °C64 °F, about 113 mm4.5 in of precipitation a month. Pack light summer clothes such as T-shirts, shorts or light dresses, an extra layer for the cooler mornings and evenings and an umbrella or light rain jacket.
- Autumn (September–November) — highs 846 to 24 °C75 °F, lows −229 to 12 °C53 °F, about 76 mm3.0 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket and an extra layer for the cooler mornings and evenings.
How Rockford compares
Compared with Aurora, about 86 km to the southeast, Rockford is on average 0.7 °C1.3 °F cooler and receives a similar amount of precipitation. The difference is largest in January (1.4 °C2.5 °F cooler).
Of the 222 places in the United States covered by World Climates, Rockford is the 212th warmest by annual mean temperature and the 113th wettest by annual precipitation. See all of them on the United States climate page.
Places in other countries with the most similar temperature and rainfall pattern: Windsor (Canada, Dfa), Brampton (Canada, Dfa) and Brantford (Canada, Dfa).
Nearby places
- Elgin 72 km · 10 °C49 °F · 983 mm39 in
- Aurora 86 km · 10 °C49 °F · 983 mm39 in
- Madison 93 km · 8 °C47 °F · 970 mm38 in
- Joliet 118 km · 10 °C51 °F · 985 mm39 in
- Chicago 128 km · 10 °C50 °F · 982 mm39 in
- Milwaukee 129 km · 9 °C48 °F · 945 mm37 in
- Davenport 148 km · 10 °C51 °F · 924 mm36 in
- Peoria 180 km · 11 °C52 °F · 983 mm39 in
Frequently asked questions
What is the warmest month in Rockford?
July is the warmest month in Rockford, with an average high of 28 °C (83 °F) and an average low of 18 °C (64 °F).
What is the coldest month in Rockford?
January is the coldest month, with an average high of -2 °C (28 °F) and an average low of -11 °C (12 °F).
When does it rain the most in Rockford?
June is the wettest month with about 129 mm (5.1 in) of precipitation; January is the driest with about 39 mm (1.5 in).
What is the best time to visit Rockford?
Judging by long-term averages, the most comfortable months are May and July–September.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.