Stockton, Illinois climate: Normal weather by month, frost dates and records
Stockton's normal year runs from 12°F January nights to 82°F July afternoons, with 38.7 inches of precipitation and 36 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.8°C, January lows of −11°C, July highs of 28°C, 982 mm of precipitation a year.
- NOAA stationStockton (3 mi NNE)
- Station IDUSC00118293
- Location42.40°N 89.99°W
- Elevation970 ft (296 m)
- From the center3 miles
- Population1,668
On October 23, the normal high in Stockton is 58°F and the normal low 38°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 Stockton.
- Jan 28° 12°
- Feb 32° 16°
- Mar 45° 27°
- Apr 59° 37°
- May 71° 49°
- Jun 79° 59°
- Jul 82° 61°
- Aug 80° 59°
- Sep 74° 51°
- Oct 62° 40°
- Nov 46° 29°
- Dec 33° 18°
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 Stockton each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 12°F. The most precipitation falls in June (5.72 in), the least in January (1.17 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 28°F | 12°F | 20.0°F | 1.17 | 10.7 | 9 | <1 | 30 | 9 h 20 min |
| February | 32°F | 16°F | 24.0°F | 1.52 | 8.1 | 8 | <1 | 26 | 10 h 30 min |
| March | 45°F | 27°F | 35.9°F | 2.20 | 4.9 | 10 | <1 | 23 | 11 h 50 min |
| April | 59°F | 37°F | 48.0°F | 3.93 | 1.3 | 12 | <1 | 9 | 13 h 20 min |
| May | 71°F | 49°F | 59.9°F | 4.13 | 0.1 | 13 | 1 | 1 | 14 h 30 min |
| June | 79°F | 59°F | 69.0°F | 5.72 | 0.0 | 12 | 2 | <1 | 15 h 20 min |
| July | 82°F | 61°F | 71.5°F | 4.50 | 0.0 | 9 | 3 | <1 | 15 h |
| August | 80°F | 59°F | 69.6°F | 4.16 | 0.0 | 10 | 2 | <1 | 14 h |
| September | 74°F | 51°F | 62.7°F | 4.22 | 0.0 | 9 | 1 | <1 | 12 h 30 min |
| October | 62°F | 40°F | 50.8°F | 3.10 | 0.5 | 9 | <1 | 7 | 11 h 10 min |
| November | 46°F | 29°F | 37.4°F | 2.32 | 2.1 | 9 | <1 | 20 | 9 h 50 min |
| December | 33°F | 18°F | 25.5°F | 1.69 | 8.0 | 10 | <1 | 28 | 9 h 10 min |
| Year (annual) | 58°F | 38°F | 47.8°F | 38.66 | 35.7 | 118 | 8 | 143 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −2°C | −11°C | −6.7°C | 30 mm | 27 cm |
| February | 0°C | −9°C | −4.4°C | 39 mm | 21 cm |
| March | 7°C | −3°C | 2.2°C | 56 mm | 12 cm |
| April | 15°C | 3°C | 8.9°C | 100 mm | 3 cm |
| May | 22°C | 9°C | 15.5°C | 105 mm | 0 cm |
| June | 26°C | 15°C | 20.6°C | 145 mm | 0 cm |
| July | 28°C | 16°C | 21.9°C | 114 mm | 0 cm |
| August | 27°C | 15°C | 20.9°C | 106 mm | 0 cm |
| September | 23°C | 11°C | 17.1°C | 107 mm | 0 cm |
| October | 16°C | 5°C | 10.4°C | 79 mm | 1 cm |
| November | 8°C | −2°C | 3.0°C | 59 mm | 5 cm |
| December | 1°C | −8°C | −3.6°C | 43 mm | 20 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00118293; 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 Stockton?
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 (9).
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 USC00118293.
When is the last frost in Stockton?
In Stockton, the last spring frost (32°F) comes after April 27 in half of years and after May 12 in one year in ten; the first autumn frost comes before October 9 in half of years and before September 26 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 271 year in 10 after May 12; 9 in 10 after April 12
- First autumn frost, half of years before
- October 91 year in 10 before September 26; 9 in 10 before October 23
NOAA puts the median frost-free season at 165 days, and the season without a hard freeze (28°F) at 185 days.
A hard freeze (28°F) comes after April 17 in half of springs and before October 21 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Stockton in zone 5a in ZIP code 61085, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Stockton's NOAA station is in zone 5a: the coldest night of a typical year reaches −16°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 USC00118293; 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 Stockton?
In a normal year in Stockton, 8 days a year reach 90°F, 143 nights fall to 32°F or colder and 118 days bring measurable precipitation.
- Days at 90°F or more
- 8a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 143a normal year
- Days that stay below freezing
- 57high of 32°F or less
- Days with 0.01 inch of precipitation
- 118a normal year
- Days with 1 inch of snow or more
- 12a normal year
The highest temperature in this station's record (since 1943) is 99°F, on June 22, 1988; the lowest is −32°F, on January 31, 2019.
The wettest calendar year on that record is 2019, with 54.81 in; the snowiest season is 2007–08, with 72.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00118293; records: ACIS (NOAA Regional Climate Centers), station USC00118293. Records use complete months only; a month missing more than three days is left out.
How sunny is Stockton?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Stockton, 3.9 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (61%).
| 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 Stockton need?
A normal year in Stockton brings 6,869 heating degree days, 28% more than the median U.S. place (5,373), and 654 cooling degree days, 28% 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 2,807 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,396 | 0 |
| February | 1,149 | 0 |
| March | 901 | 1 |
| April | 516 | 5 |
| May | 210 | 50 |
| June | 33 | 153 |
| July | 9 | 211 |
| August | 19 | 160 |
| September | 135 | 66 |
| October | 447 | 8 |
| November | 830 | 0 |
| December | 1,223 | 0 |
| Year (annual) | 6,869 | 654 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00118293. 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 Stockton been warmer than normal lately?
2025 averaged 47.9°F, 0.1°F above the 1991-2020 normal of 47.8°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 49.2°F | +1.4°F | 29.48 | 31.2 |
| 2022 | 47.0°F | −0.8°F | 44.87 | 34.1 |
| 2023 | 49.2°F | +1.4°F | 34.12 | 47.8 |
| 2024 | 50.2°F | +2.4°F | 37.84 | 28.3 |
| 2025 | 47.9°F | +0.1°F | 26.10 | 36.8 |
Over 72 complete years from 1948 to 2025, the station's annual mean temperature rose at a fitted 2.8°F per century (+0.16°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00118293; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Stockton's climate compare?
Stockton is warmer than 3 of the other 143 places with their own NOAA record in Illinois, and wetter than 46. Across the 7,247 U.S. stations with normals, its annual mean of 47.8°F is warmer than 31%.
In the Köppen classification computed from these normals, Stockton is Dfb: continental, no dry season, warm 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 Stockton 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.
- South Wayne, WI447 people · 13 mi NE
- Gratiot, WI229 people · 13 mi N
- Nora, IL110 people · 5 mi NE
- Woodford, WI83 people · 18 mi N
- Wiota, WI69 people · 17 mi N
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 Stockton's climate
What is the coldest month in Stockton?
January, with a normal high of 28°F and a normal low of 12°F. The warmest is July (82°F by day, 61°F at night).
Does it snow in Stockton?
Yes: 36 inches in a normal year, falling on 24 days with 0.1 inch or more, the most in January (10.7 inches).
What is the rainiest month in Stockton?
June, with 5.72 in of precipitation in a normal year; the driest is January with 1.17 in.
What plant hardiness zone is Stockton in?
The USDA's 2023 map puts Stockton in zone 5a in ZIP code 61085, the nearest ZIP area. By the same method at Stockton's NOAA station, the coldest night of a typical year reaches −16°F (30 years, 1991-2020): zone 5a.
How late can frost come in Stockton?
In half of years the last 32°F night comes after April 27; in one year in ten it comes after May 12. Waiting until May 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Illinois climateThe statewide normals and every place in the state
- Elizabeth, IL14 miles from this station, 47.5°F a year
- Darlington, WI20 miles from this station, 46.2°F a year
- Galena, IL21 miles from this station, 47.0°F a year
- Mount Carroll, IL21 miles from this station, 48.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made