Galesburg, Illinois climate: Normal weather by month, frost dates and records
Galesburg's normal year runs from 14°F January nights to 84°F July afternoons, with 39.0 inches of precipitation and 26 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.1°C, January lows of −10°C, July highs of 29°C, 990 mm of precipitation a year.
- NOAA stationGalesburg
- Station IDUSC00113320
- Location40.95°N 90.39°W
- Elevation761 ft (232 m)
- From the centerunder 1 mile
- Population29,289
On October 23, the normal high in Galesburg is 60°F and the normal low 40°F, and the chance of measurable rain or snow is 28%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Galesburg.
- Jan 30° 14°
- Feb 35° 17°
- Mar 48° 28°
- Apr 61° 40°
- May 72° 52°
- Jun 81° 62°
- Jul 84° 65°
- Aug 82° 63°
- Sep 76° 55°
- Oct 63° 43°
- Nov 48° 30°
- Dec 35° 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 Galesburg each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 14°F. The most precipitation falls in May (5.27 in), the least in January (1.69 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 | 30°F | 14°F | 21.9°F | 1.69 | 9.0 | 8 | <1 | 29 | 9 h 30 min |
| February | 35°F | 17°F | 26.0°F | 1.87 | 6.6 | 7 | <1 | 25 | 10 h 40 min |
| March | 48°F | 28°F | 38.0°F | 2.39 | 2.3 | 9 | <1 | 21 | 11 h 50 min |
| April | 61°F | 40°F | 50.6°F | 3.83 | 0.4 | 11 | <1 | 6 | 13 h 20 min |
| May | 72°F | 52°F | 61.8°F | 5.27 | 0.0 | 12 | 1 | <1 | 14 h 30 min |
| June | 81°F | 62°F | 71.6°F | 4.58 | 0.0 | 10 | 4 | <1 | 15 h 10 min |
| July | 84°F | 65°F | 74.7°F | 4.04 | 0.0 | 8 | 6 | <1 | 14 h 50 min |
| August | 82°F | 63°F | 72.8°F | 3.89 | 0.0 | 9 | 4 | <1 | 13 h 50 min |
| September | 76°F | 55°F | 65.5°F | 3.85 | 0.0 | 7 | 2 | <1 | 12 h 30 min |
| October | 63°F | 43°F | 52.8°F | 2.82 | 0.0 | 9 | <1 | 4 | 11 h 10 min |
| November | 48°F | 30°F | 39.0°F | 2.60 | 1.7 | 8 | <1 | 18 | 10 h |
| December | 35°F | 20°F | 27.8°F | 2.14 | 5.9 | 8 | <1 | 27 | 9 h 20 min |
| Year (annual) | 60°F | 41°F | 50.2°F | 38.97 | 25.9 | 104 | 16 | 129 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −1°C | −10°C | −5.6°C | 43 mm | 23 cm |
| February | 2°C | −8°C | −3.3°C | 47 mm | 17 cm |
| March | 9°C | −2°C | 3.3°C | 61 mm | 6 cm |
| April | 16°C | 4°C | 10.3°C | 97 mm | 1 cm |
| May | 22°C | 11°C | 16.6°C | 134 mm | 0 cm |
| June | 27°C | 17°C | 22.0°C | 116 mm | 0 cm |
| July | 29°C | 19°C | 23.7°C | 103 mm | 0 cm |
| August | 28°C | 17°C | 22.7°C | 99 mm | 0 cm |
| September | 25°C | 13°C | 18.6°C | 98 mm | 0 cm |
| October | 17°C | 6°C | 11.6°C | 72 mm | 0 cm |
| November | 9°C | −1°C | 3.9°C | 66 mm | 4 cm |
| December | 2°C | −7°C | −2.3°C | 54 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00113320; 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 Galesburg?
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 (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 USC00113320.
When is the last frost in Galesburg?
In Galesburg, the last spring frost (32°F) comes after April 20 in half of years and after May 5 in one year in ten; the first autumn frost comes before October 19 in half of years and before October 4 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 201 year in 10 after May 5; 9 in 10 after April 6
- First autumn frost, half of years before
- October 191 year in 10 before October 4; 9 in 10 before October 30
NOAA puts the median frost-free season at 180 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 28 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Galesburg in zone 5b in ZIP code 61401. By the map's own method, the average of each year's coldest night over 1991-2020, Galesburg's NOAA station is in zone 5b: the coldest night of a typical year reaches −11°F (29 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 USC00113320; 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 Galesburg?
In a normal year in Galesburg, 16 days a year reach 90°F, 129 nights fall to 32°F or colder and 104 days bring measurable precipitation.
- Days at 90°F or more
- 16a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 129a normal year
- Days that stay below freezing
- 47high of 32°F or less
- Days with 0.01 inch of precipitation
- 104a normal year
- Days with 1 inch of snow or more
- 9a normal year
The highest temperature in this station's record (since 1896) is 112°F, on July 15, 1936; the lowest is −28°F, on February 13, 1905.
The wettest calendar year on that record is 2009, with 54.27 in; the snowiest season is 1959–60, with 49.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00113320; records: ACIS (NOAA Regional Climate Centers), station USC00113320. Records use complete months only; a month missing more than three days is left out.
How sunny is Galesburg?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Galesburg, 4.1 kWh per square metre a day. July is the sunniest month (82%) and January the cloudiest (63%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 63% | 1.9 |
| February | 68% | 2.8 |
| March | 68% | 3.8 |
| April | 70% | 4.9 |
| May | 73% | 5.6 |
| June | 79% | 6.3 |
| July | 82% | 6.4 |
| August | 81% | 5.5 |
| September | 82% | 4.7 |
| October | 73% | 3.2 |
| November | 70% | 2.2 |
| December | 63% | 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 Galesburg need?
A normal year in Galesburg brings 6,322 heating degree days, 18% more than the median U.S. place (5,373), and 970 cooling degree days, 7% 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 3,330 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,336 | 0 |
| February | 1,092 | 0 |
| March | 837 | 1 |
| April | 441 | 9 |
| May | 168 | 70 |
| June | 19 | 217 |
| July | 2 | 303 |
| August | 6 | 250 |
| September | 93 | 107 |
| October | 394 | 14 |
| November | 782 | 0 |
| December | 1,153 | 0 |
| Year (annual) | 6,322 | 970 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00113320. 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 Galesburg been warmer than normal lately?
2025 averaged 51.6°F, 1.4°F above the 1991-2020 normal of 50.2°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 51.4°F | +1.2°F | 42.32 | 18.1 |
| 2022 | 49.3°F | −0.9°F | 36.12 | 31.3 |
| 2023 | 52.4°F | +2.2°F | 37.95 | 13.7 |
| 2024 | 53.2°F | +3.0°F | 38.70 | 21.1 |
| 2025 | 51.6°F | +1.4°F | 31.20 | 19.1 |
Over 80 complete years from 1899 to 2025, the station's annual mean temperature rose at a fitted 1.7°F per century (+0.10°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00113320; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Galesburg's climate compare?
Galesburg is warmer than 37 of the other 143 places with their own NOAA record in Illinois, and wetter than 51. 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, Galesburg 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 Galesburg share this climate record?
4 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.
- Wataga, IL723 people · 8 mi NE
- Henderson, IL257 people · 6 mi N
- Rio, IL205 people · 11 mi N
- North Henderson, IL159 people · 11 mi NW
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 Galesburg's climate
What is the coldest month in Galesburg?
January, with a normal high of 30°F and a normal low of 14°F. The warmest is July (84°F by day, 65°F at night).
Does it snow in Galesburg?
Yes: 26 inches in a normal year, falling on 14 days with 0.1 inch or more, the most in January (9.0 inches).
What is the rainiest month in Galesburg?
May, with 5.27 in of precipitation in a normal year; the driest is January with 1.69 in.
What plant hardiness zone is Galesburg in?
The USDA's 2023 map puts Galesburg in zone 5b in ZIP code 61401. By the same method at Galesburg's NOAA station, the coldest night of a typical year reaches −11°F (29 years, 1991-2020): zone 5b.
How late can frost come in Galesburg?
In half of years the last 32°F night comes after April 20; 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
- Galesburg in OctoberThis month day by day, its records and recent years
- Illinois climateThe statewide normals and every place in the state
- Knoxville, IL6 miles from this station, 50.4°F a year
- Monmouth, IL13 miles from this station, 50.6°F a year
- Altona, IL17 miles from this station, 49.0°F a year
- Avon, IL20 miles from this station, 49.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made