Bloomington, Illinois climate: Normal weather by month, frost dates and records
Bloomington's normal year runs from 16°F January nights to 84°F July afternoons, with 40.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.1°C, January lows of −9°C, July highs of 29°C, 1,027 mm of precipitation a year.
- NOAA stationBloomington (5 mi W)
- Station IDUSC00110764
- Location40.49°N 89.09°W
- Elevation852 ft (260 m)
- From the center6 miles
- Population79,232
On October 23, the normal high in Bloomington is 59°F and the normal low 40°F, and the chance of measurable rain or snow is 29%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Bloomington.
- Jan 31° 16°
- Feb 36° 19°
- Mar 49° 29°
- Apr 62° 39°
- May 72° 50°
- Jun 81° 60°
- Jul 84° 63°
- Aug 83° 61°
- Sep 76° 54°
- Oct 63° 42°
- Nov 48° 30°
- Dec 35° 21°
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 Bloomington each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 16°F. The most precipitation falls in May (4.83 in), the least in February (2.08 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. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 31°F | 16°F | 23.2°F | 2.40 | 9 | <1 | 30 | 9 h 30 min |
| February | 36°F | 19°F | 27.7°F | 2.08 | 8 | <1 | 26 | 10 h 40 min |
| March | 49°F | 29°F | 38.7°F | 2.61 | 9 | <1 | 21 | 11 h 50 min |
| April | 62°F | 39°F | 50.5°F | 4.08 | 11 | <1 | 6 | 13 h 10 min |
| May | 72°F | 50°F | 61.3°F | 4.83 | 12 | 1 | <1 | 14 h 20 min |
| June | 81°F | 60°F | 70.5°F | 4.58 | 11 | 5 | <1 | 15 h |
| July | 84°F | 63°F | 73.8°F | 4.05 | 8 | 9 | <1 | 14 h 50 min |
| August | 83°F | 61°F | 72.0°F | 4.13 | 9 | 7 | <1 | 13 h 50 min |
| September | 76°F | 54°F | 65.2°F | 3.15 | 8 | 3 | <1 | 12 h 30 min |
| October | 63°F | 42°F | 52.4°F | 3.45 | 10 | <1 | 4 | 11 h 10 min |
| November | 48°F | 30°F | 38.9°F | 2.80 | 7 | <1 | 17 | 10 h |
| December | 35°F | 21°F | 28.3°F | 2.28 | 10 | <1 | 27 | 9 h 20 min |
| Year (annual) | 60°F | 40°F | 50.2°F | 40.44 | 112 | 26 | 132 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −1°C | −9°C | −4.9°C | 61 mm |
| February | 2°C | −7°C | −2.4°C | 53 mm |
| March | 9°C | −2°C | 3.7°C | 66 mm |
| April | 17°C | 4°C | 10.3°C | 104 mm |
| May | 22°C | 10°C | 16.3°C | 123 mm |
| June | 27°C | 15°C | 21.4°C | 116 mm |
| July | 29°C | 17°C | 23.2°C | 103 mm |
| August | 28°C | 16°C | 22.2°C | 105 mm |
| September | 25°C | 12°C | 18.4°C | 80 mm |
| October | 17°C | 6°C | 11.3°C | 88 mm |
| November | 9°C | −1°C | 3.8°C | 71 mm |
| December | 2°C | −6°C | −2.1°C | 58 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Normal (8 miles away), gets 20 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00110764; 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 Bloomington?
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 USC00110764.
When is the last frost in Bloomington?
In Bloomington, the last spring frost (32°F) comes after April 21 in half of years and after May 5 in one year in ten; the first autumn frost comes before October 20 in half of years and before October 9 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 5; 9 in 10 after April 7
- First autumn frost, half of years before
- October 201 year in 10 before October 9; 9 in 10 before November 1
NOAA puts the median frost-free season at 181 days, and the season without a hard freeze (28°F) at 203 days.
A hard freeze (28°F) comes after April 9 in half of springs and before October 30 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Bloomington in zone 6a across its 2 ZIP code areas (6a in 61704, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Bloomington's NOAA station is in zone 6a: the coldest night of a typical year reaches −8°F (15 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 USC00110764; 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 Bloomington ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Bloomington's 2 ZIP code areas are all in zone 6a. 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 Bloomington?
In a normal year in Bloomington, 26 days a year reach 90°F (1 of them 100°F or more), 132 nights fall to 32°F or colder and 112 days bring measurable precipitation.
- Days at 90°F or more
- 26a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 132a normal year
- Days that stay below freezing
- 44high of 32°F or less
- Days with 0.01 inch of precipitation
- 112a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00110764.
How sunny is Bloomington?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Bloomington, 4.1 kWh per square metre a day. July is the sunniest month (83%) and December the cloudiest (62%). Among the 459 U.S. places of 50,000 or more, that ranks tied 330th (with 21 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 64% | 1.9 |
| February | 67% | 2.8 |
| March | 68% | 3.7 |
| April | 71% | 4.9 |
| May | 72% | 5.6 |
| June | 79% | 6.3 |
| July | 83% | 6.4 |
| August | 81% | 5.6 |
| September | 81% | 4.7 |
| October | 73% | 3.2 |
| November | 70% | 2.2 |
| 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 Bloomington need?
A normal year in Bloomington brings 6,223 heating degree days, 16% more than the median U.S. place (5,373), and 867 cooling degree days, 4% 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 3,204 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,294 | 0 |
| February | 1,044 | 0 |
| March | 817 | 1 |
| April | 444 | 8 |
| May | 174 | 60 |
| June | 22 | 186 |
| July | 5 | 277 |
| August | 9 | 226 |
| September | 92 | 98 |
| October | 401 | 12 |
| November | 783 | 0 |
| December | 1,138 | 0 |
| Year (annual) | 6,223 | 867 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00110764. 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.
How does Bloomington's climate compare?
Bloomington is warmer than 37 of the other 143 places with their own NOAA record in Illinois, and wetter than 81. Across the 7,247 U.S. stations with normals, its annual mean of 50.2°F is warmer than 41%.
In the Köppen classification computed from these normals, Bloomington 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 Bloomington 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.
- Heyworth, IL2,883 people · 13 mi SE
- Twin Grove, IL1,554 people · 1 mi SW
- Minier, IL1,137 people · 12 mi W
- Danvers, IL1,077 people · 6 mi NW
- McLean, IL736 people · 13 mi S
- Stanford, IL588 people · 8 mi SW
- Wapella, IL503 people · 19 mi S
- Shirley, IL73 people · 6 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 Bloomington's climate
What is the coldest month in Bloomington?
January, with a normal high of 31°F and a normal low of 16°F. The warmest is July (84°F by day, 63°F at night).
Does it snow in Bloomington?
Yes. NOAA publishes no 1991-2020 snowfall normal for Bloomington's NOAA station; the nearest record that keeps one, Normal (8 miles away), records 20 inches of snow in a normal year.
What is the rainiest month in Bloomington?
May, with 4.83 in of precipitation in a normal year; the driest is February with 2.08 in.
What plant hardiness zone is Bloomington in?
The USDA's 2023 map puts Bloomington in zone 6a across its 2 ZIP code areas (6a in 61704, the largest). By the same method at Bloomington's NOAA station, the coldest night of a typical year reaches −8°F (15 years, 1991-2020): zone 6a.
How late can frost come in Bloomington?
In half of years the last 32°F night comes after April 21; in one year in ten it comes after May 5. Waiting until May 5 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Bloomington in OctoberThis month day by day, its records and recent years
- Illinois climateThe statewide normals and every place in the state
- Normal, IL9 miles from this station, 51.1°F a year
- Congerville, IL12 miles from this station, 52.0°F a year
- Chenoa, IL26 miles from this station, 50.5°F a year
- Lincoln, IL27 miles from this station, 52.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made