Rantoul, Illinois climate: Normal weather by month, frost dates and records
Rantoul's normal year runs from 16°F January nights to 88°F July afternoons, with 40.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 11.3°C, January lows of −9°C, July highs of 31°C, 1,025 mm of precipitation a year.
- NOAA stationRantoul
- Station IDUSW00014806
- Location40.31°N 88.16°W
- Elevation740 ft (226 m)
- From the centerunder 1 mile
- Population12,268
On October 23, the normal high in Rantoul is 64°F and the normal low 40°F, and the chance of measurable rain or snow is 27%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Rantoul.
- Jan 34° 16°
- Feb 40° 20°
- Mar 51° 29°
- Apr 64° 40°
- May 75° 51°
- Jun 85° 62°
- Jul 88° 64°
- Aug 86° 62°
- Sep 81° 54°
- Oct 67° 42°
- Nov 52° 31°
- Dec 40° 22°
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 Rantoul each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 16°F. The most precipitation falls in June (4.61 in), the least in February (2.01 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 34°F | 16°F | 25.1°F | 2.54 | 8 | <1 | 29 | 9 h 40 min |
| February | 40°F | 20°F | 29.6°F | 2.01 | 7 | <1 | 25 | 10 h 40 min |
| March | 51°F | 29°F | 40.4°F | 2.58 | 9 | <1 | 21 | 11 h 50 min |
| April | 64°F | 40°F | 51.9°F | 3.98 | 10 | <1 | 7 | 13 h 10 min |
| May | 75°F | 51°F | 63.3°F | 4.33 | 11 | 2 | <1 | 14 h 20 min |
| June | 85°F | 62°F | 73.3°F | 4.61 | 10 | 8 | <1 | 15 h |
| July | 88°F | 64°F | 75.8°F | 4.44 | 9 | 11 | <1 | 14 h 50 min |
| August | 86°F | 62°F | 73.7°F | 3.86 | 8 | 7 | <1 | 13 h 50 min |
| September | 81°F | 54°F | 67.5°F | 3.28 | 7 | 4 | <1 | 12 h 30 min |
| October | 67°F | 42°F | 54.7°F | 3.32 | 8 | <1 | 5 | 11 h 10 min |
| November | 52°F | 31°F | 41.8°F | 3.19 | 9 | <1 | 18 | 10 h |
| December | 40°F | 22°F | 30.9°F | 2.21 | 7 | <1 | 27 | 9 h 20 min |
| Year (annual) | 64°F | 41°F | 52.3°F | 40.35 | 102 | 34 | 131 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 1°C | −9°C | −3.8°C | 65 mm |
| February | 4°C | −7°C | −1.3°C | 51 mm |
| March | 11°C | −1°C | 4.7°C | 66 mm |
| April | 18°C | 4°C | 11.1°C | 101 mm |
| May | 24°C | 11°C | 17.4°C | 110 mm |
| June | 29°C | 17°C | 22.9°C | 117 mm |
| July | 31°C | 18°C | 24.3°C | 113 mm |
| August | 30°C | 16°C | 23.2°C | 98 mm |
| September | 27°C | 12°C | 19.7°C | 83 mm |
| October | 20°C | 6°C | 12.6°C | 84 mm |
| November | 11°C | 0°C | 5.4°C | 81 mm |
| December | 4°C | −5°C | −0.6°C | 56 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Paxton (10 miles away), gets 18 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014806; 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 Rantoul?
Normal highs sit between 65°F and 85°F in May, June, September and October. Of those, September has the fewest days with rain (7).
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 USW00014806.
When is the last frost in Rantoul?
In Rantoul, the last spring frost (32°F) comes after April 21 in half of years and after May 6 in one year in ten; the first autumn frost comes before October 18 in half of years and before October 5 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 211 year in 10 after May 6; 9 in 10 after April 7
- First autumn frost, half of years before
- October 181 year in 10 before October 5; 9 in 10 before October 31
NOAA puts the median frost-free season at 179 days, and the season without a hard freeze (28°F) at 199 days.
A hard freeze (28°F) comes after April 10 in half of springs and before October 29 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Rantoul in zone 6a in ZIP code 61866. By the map's own method, the average of each year's coldest night over 1991-2020, Rantoul's NOAA station is in zone 6a: the coldest night of a typical year reaches −8°F (19 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 USW00014806; 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.
How hot and how cold does it get in Rantoul?
In a normal year in Rantoul, 34 days a year reach 90°F (1 of them 100°F or more), 131 nights fall to 32°F or colder and 102 days bring measurable precipitation.
- Days at 90°F or more
- 34a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 131a normal year
- Days that stay below freezing
- 33high of 32°F or less
- Days with 0.01 inch of precipitation
- 102a normal year
The highest temperature in this station's record (since 1896) is 106°F, on July 21, 1901; the lowest is −24°F, on February 13, 1905.
The wettest calendar year on that record is 1990, with 52.28 in; the snowiest season is 1981–82, with 58.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00014806; records: ACIS (NOAA Regional Climate Centers), station USW00014806. Records use complete months only; a month missing more than three days is left out.
How sunny is Rantoul?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Rantoul, 4.0 kWh per square metre a day. July is the sunniest month (82%) and December the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 64% | 1.9 |
| February | 67% | 2.7 |
| March | 67% | 3.7 |
| April | 71% | 4.8 |
| May | 72% | 5.5 |
| June | 79% | 6.3 |
| July | 82% | 6.3 |
| August | 81% | 5.5 |
| September | 81% | 4.6 |
| October | 72% | 3.1 |
| November | 69% | 2.1 |
| December | 62% | 1.6 |
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 Rantoul need?
A normal year in Rantoul brings 5,719 heating degree days, 6% more than the median U.S. place (5,373), and 1,145 cooling degree days, 26% more 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 3,623 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,237 | 0 |
| February | 991 | 0 |
| March | 766 | 2 |
| April | 403 | 11 |
| May | 143 | 92 |
| June | 16 | 265 |
| July | 2 | 336 |
| August | 5 | 276 |
| September | 66 | 141 |
| October | 340 | 21 |
| November | 695 | 1 |
| December | 1,056 | 0 |
| Year (annual) | 5,719 | 1,145 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014806. 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 Rantoul been warmer than normal lately?
2023 averaged 54.1°F, 1.8°F above the 1991-2020 normal of 52.3°F. 2 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 53.1°F | +0.9°F | 46.38 |
| 2022 | 51.1°F | −1.2°F | 38.08 |
| 2023 | 54.1°F | +1.8°F | 31.64 |
Over 45 complete years from 1949 to 2023, the station's annual mean temperature rose at a fitted 0.6°F per century (+0.03°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00014806; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Rantoul's climate compare?
Rantoul is warmer than 80 of the other 143 places with their own NOAA record in Illinois, and wetter than 77. Across the 7,247 U.S. stations with normals, its annual mean of 52.3°F is warmer than 51%.
In the Köppen classification computed from these normals, Rantoul 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 Rantoul share this climate record?
5 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.
- Fisher, IL2,092 people · 10 mi W
- Thomasboro, IL1,023 people · 5 mi S
- Gifford, IL906 people · 7 mi E
- Penfield, IL195 people · 11 mi E
- Dewey, IL71 people · 7 mi W
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 Rantoul's climate
What is the coldest month in Rantoul?
January, with a normal high of 34°F and a normal low of 16°F. The warmest is July (88°F by day, 64°F at night).
Does it snow in Rantoul?
Yes. NOAA publishes no 1991-2020 snowfall normal for Rantoul's NOAA station; the nearest record that keeps one, Paxton (10 miles away), records 18 inches of snow in a normal year.
What is the rainiest month in Rantoul?
June, with 4.61 in of precipitation in a normal year; the driest is February with 2.01 in.
What plant hardiness zone is Rantoul in?
The USDA's 2023 map puts Rantoul in zone 6a in ZIP code 61866. By the same method at Rantoul's NOAA station, the coldest night of a typical year reaches −8°F (19 years, 1991-2020): zone 6a.
How late can frost come in Rantoul?
In half of years the last 32°F night comes after April 21; in one year in ten it comes after May 6. Waiting until May 6 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Illinois climateThe statewide normals and every place in the state
- Paxton, IL10 miles from this station, 50.5°F a year
- Gibson City, IL16 miles from this station, 50.7°F a year
- Ogden, IL17 miles from this station, 52.2°F a year
- Champaign, IL20 miles from this station, 52.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made