Rockford, Illinois climate: Normal weather by month, frost dates and records
Rockford's normal year runs from 15°F January nights to 84°F July afternoons, with 37.2 inches of precipitation and 37 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.7°C, January lows of −10°C, July highs of 29°C, 946 mm of precipitation a year.
- NOAA stationRockford Greater Rockford Airport
- Station IDUSW00094822
- Location42.19°N 89.09°W
- Elevation730 ft (223 m)
- From the center5 miles
- Population147,486
On October 14, the normal high in Rockford is 63°F and the normal low 42°F, and the chance of measurable rain or snow is 30%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Rockford.
- Jan 29° 15°
- Feb 33° 18°
- Mar 47° 28°
- Apr 60° 39°
- May 71° 50°
- Jun 81° 60°
- Jul 84° 64°
- Aug 82° 62°
- Sep 75° 54°
- Oct 62° 42°
- Nov 47° 31°
- Dec 34° 20°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Rockford each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 15°F. The most precipitation falls in June (5.23 in), the least in January (1.60 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 29°F | 15°F | 21.8°F | 1.60 | 10.9 | 10 | <1 | 29 | 9 h 20 min |
| February | 33°F | 18°F | 25.6°F | 1.63 | 8.5 | 9 | <1 | 26 | 10 h 30 min |
| March | 47°F | 28°F | 37.3°F | 2.40 | 4.9 | 11 | <1 | 22 | 11 h 50 min |
| April | 60°F | 39°F | 49.1°F | 3.75 | 0.9 | 12 | <1 | 7 | 13 h 20 min |
| May | 71°F | 50°F | 60.4°F | 4.18 | 0.0 | 13 | 1 | 1 | 14 h 30 min |
| June | 81°F | 60°F | 70.1°F | 5.23 | 0.0 | 11 | 4 | <1 | 15 h 10 min |
| July | 84°F | 64°F | 73.8°F | 3.81 | 0.0 | 9 | 5 | <1 | 15 h |
| August | 82°F | 62°F | 71.9°F | 4.19 | 0.0 | 9 | 3 | <1 | 14 h |
| September | 75°F | 54°F | 64.4°F | 3.62 | 0.0 | 8 | 2 | <1 | 12 h 30 min |
| October | 62°F | 42°F | 52.0°F | 2.63 | 0.2 | 10 | <1 | 5 | 11 h 10 min |
| November | 47°F | 31°F | 38.8°F | 2.27 | 2.3 | 9 | <1 | 18 | 9 h 50 min |
| December | 34°F | 20°F | 27.3°F | 1.93 | 9.4 | 10 | <1 | 27 | 9 h 10 min |
| Year (annual) | 59°F | 40°F | 49.4°F | 37.24 | 37.1 | 121 | 15 | 136 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −2°C | −10°C | −5.7°C | 41 mm | 28 cm |
| February | 1°C | −8°C | −3.6°C | 41 mm | 22 cm |
| March | 8°C | −2°C | 2.9°C | 61 mm | 12 cm |
| April | 15°C | 4°C | 9.5°C | 95 mm | 2 cm |
| May | 22°C | 10°C | 15.8°C | 106 mm | 0 cm |
| June | 27°C | 15°C | 21.2°C | 133 mm | 0 cm |
| July | 29°C | 18°C | 23.2°C | 97 mm | 0 cm |
| August | 28°C | 17°C | 22.2°C | 106 mm | 0 cm |
| September | 24°C | 12°C | 18.0°C | 92 mm | 0 cm |
| October | 17°C | 5°C | 11.1°C | 67 mm | 1 cm |
| November | 8°C | −1°C | 3.8°C | 58 mm | 6 cm |
| December | 1°C | −7°C | −2.6°C | 49 mm | 24 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094822; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Rockford?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (8).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094822.
When is the last frost in Rockford?
In Rockford, the last spring frost (32°F) comes after April 24 in half of years and after May 8 in one year in ten; the first autumn frost comes before October 17 in half of years and before October 2 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 241 year in 10 after May 8; 9 in 10 after April 10
- First autumn frost, half of years before
- October 171 year in 10 before October 2; 9 in 10 before October 30
NOAA puts the median frost-free season at 174 days, and the season without a hard freeze (28°F) at 197 days.
A hard freeze (28°F) comes after April 13 in half of springs and before October 28 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Rockford in zone 5b across its 8 ZIP code areas (5b in 61109, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Rockford's NOAA station is in zone 5b: the coldest night of a typical year reaches −14°F (30 complete years).
Frost dates for every NOAA station in Illinois · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00094822; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Rockford ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Rockford's 8 ZIP code areas are all in zone 5b. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Rockford?
In a normal year in Rockford, 15 days a year reach 90°F, 136 nights fall to 32°F or colder and 121 days bring measurable precipitation.
- Days at 90°F or more
- 15a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 136a normal year
- Days that stay below freezing
- 50high of 32°F or less
- Days with 0.01 inch of precipitation
- 121a normal year
- Days with 1 inch of snow or more
- 11a normal year
The highest temperature in Rockford's official record (kept by the National Weather Service since 1893) is 112°F, on July 14, 1936; the lowest is −31°F, on January 31, 2019.
The wettest calendar year on that record is 1973, with 56.48 in; the snowiest season is 1978–79, with 74.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00094822; records: ACIS (NOAA Regional Climate Centers), NWS threaded record RFDthr. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Rockford, and how clear are its skies?
The summer (June-August) dew point averages 61°F. The muggiest month is July, with an average dew point of 62°F; the driest air comes in January (16°F). March is the windiest month (10.9 mph on average), and August has the most clear or nearly clear hours (51%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 16°F | 75% | 66% | 9.5 mph | 35% | 49% |
| February | 21°F | 71% | 59% | 10.1 mph | 34% | 46% |
| March | 31°F | 63% | 46% | 10.9 mph | 33% | 44% |
| April | 40°F | 61% | 45% | 10.2 mph | 35% | 42% |
| May | 53°F | 65% | 49% | 8.4 mph | 34% | 30% |
| June | 61°F | 69% | 51% | 7.4 mph | 42% | 22% |
| July | 62°F | 71% | 52% | 6.7 mph | 45% | 21% |
| August | 60°F | 73% | 52% | 6.9 mph | 51% | 20% |
| September | 47°F | 70% | 48% | 8.2 mph | 47% | 28% |
| October | 36°F | 70% | 54% | 9.5 mph | 37% | 43% |
| November | 26°F | 75% | 65% | 9.5 mph | 28% | 55% |
| December | 18°F | 77% | 68% | 9.6 mph | 32% | 51% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00094822. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Rockford?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Rockford, 3.9 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (61%). Among the 459 U.S. places of 50,000 or more, that ranks tied 352nd (with 32 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 66% | 1.8 |
| February | 70% | 2.8 |
| March | 69% | 3.8 |
| April | 68% | 4.7 |
| May | 71% | 5.5 |
| June | 76% | 6.2 |
| July | 80% | 6.3 |
| August | 79% | 5.5 |
| September | 78% | 4.4 |
| October | 70% | 2.9 |
| November | 67% | 1.9 |
| December | 61% | 1.4 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Rockford need?
A normal year in Rockford brings 6,497 heating degree days, 21% more than the median U.S. place (5,373), and 838 cooling degree days, 8% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,083 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,339 | 0 |
| February | 1,103 | 0 |
| March | 860 | 2 |
| April | 482 | 5 |
| May | 199 | 54 |
| June | 27 | 182 |
| July | 3 | 274 |
| August | 8 | 222 |
| September | 107 | 89 |
| October | 412 | 11 |
| November | 786 | 0 |
| December | 1,170 | 0 |
| Year (annual) | 6,497 | 838 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094822. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Rockford been warmer than normal lately?
2025 averaged 50.1°F, 0.7°F above the 1991-2020 normal of 49.4°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 52.0°F | +2.6°F | 24.19 | 30.2 |
| 2022 | 49.2°F | −0.2°F | 39.47 | 24.7 |
| 2023 | 51.3°F | +1.9°F | 32.46 | 34.2 |
| 2024 | 52.8°F | +3.4°F | 35.49 | 28.2 |
| 2025 | 50.1°F | +0.7°F | 27.74 | 31.1 |
Over 67 complete years from 1951 to 2025, the station's annual mean temperature rose at a fitted 3.6°F per century (+0.20°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00094822; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Rockford's climate compare?
Rockford is warmer than 25 of the other 143 places with their own NOAA record in Illinois, and wetter than 17. Across the 7,247 U.S. stations with normals, its annual mean of 49.4°F is warmer than 38%.
In the Köppen classification computed from these normals, Rockford is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Rockford share this climate record?
8 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Byron, IL3,764 people · 10 mi SW
- Winnebago, IL2,907 people · 9 mi NW
- Cherry Valley, IL2,888 people · 7 mi NE
- Davis Junction, IL2,534 people · 5 mi S
- Stillman Valley, IL1,052 people · 7 mi SW
- New Milford, IL807 people · 3 mi SE
- Monroe Center, IL406 people · 8 mi SE
- Holcomb, IL175 people · 9 mi S
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Rockford's climate
What is the coldest month in Rockford?
January, with a normal high of 29°F and a normal low of 15°F. The warmest is July (84°F by day, 64°F at night).
Does it snow in Rockford?
Yes: 37 inches in a normal year, falling on 28 days with 0.1 inch or more, the most in January (10.9 inches).
What is the rainiest month in Rockford?
June, with 5.23 in of precipitation in a normal year; the driest is January with 1.60 in.
What plant hardiness zone is Rockford in?
The USDA's 2023 map puts Rockford in zone 5b across its 8 ZIP code areas (5b in 61109, the largest). By the same method at Rockford's NOAA station, the coldest night of a typical year reaches −14°F (30 years, 1991-2020): zone 5b.
How late can frost come in Rockford?
In half of years the last 32°F night comes after April 24; in one year in ten it comes after May 8. Waiting until May 8 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Rockford in OctoberThis month day by day, its records and recent years
- Illinois climateThe statewide normals and every place in the state
- Rochelle, IL19 miles from this station, 47.9°F a year
- Beloit, WI22 miles from this station, 45.4°F a year
- DeKalb, IL24 miles from this station, 48.6°F a year
- Marengo, IL25 miles from this station, 48.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made