Avon, Illinois climate: Normal weather by month, frost dates and records
Avon's normal year runs from 13°F January nights to 84°F July afternoons, with 37.6 inches of precipitation and 24 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.6°C, January lows of −11°C, July highs of 29°C, 956 mm of precipitation a year.
- NOAA stationAvon
- Station IDUSC00110356
- Location40.66°N 90.44°W
- Elevation640 ft (195 m)
- From the centerunder 1 mile
- Population671
On October 23, the normal high in Avon is 61°F and the normal low 37°F, and the chance of measurable rain or snow is 24%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Avon.
- Jan 31° 13°
- Feb 36° 17°
- Mar 48° 26°
- Apr 62° 37°
- May 72° 49°
- Jun 81° 59°
- Jul 84° 62°
- Aug 82° 60°
- Sep 77° 51°
- Oct 64° 40°
- Nov 49° 29°
- Dec 36° 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 Avon each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 13°F. The most precipitation falls in May (4.95 in), the least in January (1.83 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 31°F | 13°F | 21.9°F | 1.83 | 7.4 | 7 | <1 | 30 | 9 h 30 min |
| February | 36°F | 17°F | 26.1°F | 1.84 | 6.0 | 7 | <1 | 26 | 10 h 40 min |
| March | 48°F | 26°F | 37.4°F | 2.38 | 2.7 | 8 | <1 | 22 | 11 h 50 min |
| April | 62°F | 37°F | 49.4°F | 3.62 | 1.1 | 10 | <1 | 10 | 13 h 10 min |
| May | 72°F | 49°F | 60.7°F | 4.95 | 0.0 | 11 | 1 | 1 | 14 h 20 min |
| June | 81°F | 59°F | 69.8°F | 4.38 | 0.0 | 9 | 3 | <1 | 15 h |
| July | 84°F | 62°F | 73.0°F | 4.23 | 0.0 | 8 | 6 | <1 | 14 h 50 min |
| August | 82°F | 60°F | 71.1°F | 3.67 | 0.0 | 8 | 4 | <1 | 13 h 50 min |
| September | 77°F | 51°F | 63.9°F | 3.65 | 0.0 | 7 | 2 | <1 | 12 h 30 min |
| October | 64°F | 40°F | 52.0°F | 2.85 | 0.0 | 8 | <1 | 8 | 11 h 10 min |
| November | 49°F | 29°F | 39.0°F | 2.37 | 1.0 | 7 | <1 | 19 | 10 h |
| December | 36°F | 20°F | 28.0°F | 1.86 | 5.8 | 7 | <1 | 27 | 9 h 20 min |
| Year (annual) | 60°F | 39°F | 49.3°F | 37.63 | 24.0 | 94 | 16 | 144 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −1°C | −11°C | −5.6°C | 46 mm | 19 cm |
| February | 2°C | −9°C | −3.3°C | 47 mm | 15 cm |
| March | 9°C | −3°C | 3.0°C | 60 mm | 7 cm |
| April | 17°C | 3°C | 9.7°C | 92 mm | 3 cm |
| May | 22°C | 10°C | 15.9°C | 126 mm | 0 cm |
| June | 27°C | 15°C | 21.0°C | 111 mm | 0 cm |
| July | 29°C | 17°C | 22.8°C | 107 mm | 0 cm |
| August | 28°C | 15°C | 21.7°C | 93 mm | 0 cm |
| September | 25°C | 11°C | 17.7°C | 93 mm | 0 cm |
| October | 18°C | 4°C | 11.1°C | 72 mm | 0 cm |
| November | 10°C | −2°C | 3.9°C | 60 mm | 3 cm |
| December | 2°C | −7°C | −2.2°C | 47 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00110356; 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 Avon?
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 USC00110356.
When is the last frost in Avon?
In Avon, the last spring frost (32°F) comes after April 22 in half of years and after May 8 in one year in ten; the first autumn frost comes before October 19 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 221 year in 10 after May 8; 9 in 10 after April 7
- First autumn frost, half of years before
- October 191 year in 10 before October 5; 9 in 10 before October 29
NOAA puts the median frost-free season at 177 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 27 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Avon in zone 5b in ZIP code 61415, the nearest ZIP area.
Frost dates for every NOAA station in Illinois · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00110356; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Avon?
In a normal year in Avon, 16 days a year reach 90°F, 144 nights fall to 32°F or colder and 94 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
- 144a normal year
- Days that stay below freezing
- 46high of 32°F or less
- Days with 0.01 inch of precipitation
- 94a normal year
- Days with 1 inch of snow or more
- 9a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00110356.
How sunny is Avon?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Avon, 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 Avon need?
A normal year in Avon brings 6,438 heating degree days, 20% more than the median U.S. place (5,373), and 765 cooling degree days, 16% 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 3,044 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,336 | 0 |
| February | 1,091 | 0 |
| March | 859 | 1 |
| April | 472 | 4 |
| May | 191 | 58 |
| June | 22 | 165 |
| July | 6 | 254 |
| August | 13 | 200 |
| September | 104 | 71 |
| October | 415 | 12 |
| November | 782 | 0 |
| December | 1,149 | 0 |
| Year (annual) | 6,438 | 765 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00110356. 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 Avon been warmer than normal lately?
2025 averaged 50.7°F, 1.4°F above the 1991-2020 normal of 49.3°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 50.8°F | +1.5°F | 42.68 | 16.5 |
| 2022 | 48.8°F | −0.5°F | 28.90 | 28.5 |
| 2023 | 51.6°F | +2.3°F | 31.71 | 9.1 |
| 2024 | 52.3°F | +3.0°F | 38.47 | 14.9 |
| 2025 | 50.7°F | +1.4°F | 26.84 | 25.3 |
Source: observed years: ACIS, station USC00110356. A year counts only with all twelve months complete.
How does Avon's climate compare?
Avon is warmer than 21 of the other 143 places with their own NOAA record in Illinois, and wetter than 23. Across the 7,247 U.S. stations with normals, its annual mean of 49.3°F is warmer than 37%.
In the Köppen classification computed from these normals, Avon 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 Avon 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.
- Roseville, IL839 people · 12 mi W
- Fairview, IL410 people · 14 mi E
- London Mills, IL342 people · 10 mi E
- St. Augustine, IL114 people · 4 mi NE
- Ellisville, IL85 people · 8 mi E
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 Avon's climate
What is the coldest month in Avon?
January, with a normal high of 31°F and a normal low of 13°F. The warmest is July (84°F by day, 62°F at night).
Does it snow in Avon?
Yes: 24 inches in a normal year, falling on 12 days with 0.1 inch or more, the most in January (7.4 inches).
What is the rainiest month in Avon?
May, with 4.95 in of precipitation in a normal year; the driest is January with 1.83 in.
What plant hardiness zone is Avon in?
The USDA's 2023 map puts Avon in zone 5b in ZIP code 61415, the nearest ZIP area.
How late can frost come in Avon?
In half of years the last 32°F night comes after April 22; 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
- Illinois climateThe statewide normals and every place in the state
- Prairie City, IL5 miles from this station, 51.5°F a year
- Knoxville, IL19 miles from this station, 50.4°F a year
- Galesburg, IL20 miles from this station, 50.2°F a year
- Monmouth, IL22 miles from this station, 50.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made