Grayville, Illinois climate: Normal weather by month, frost dates and records
Grayville's normal year runs from 24°F January nights to 89°F July afternoons, with 50.0 inches of precipitation and 12 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 13.4°C, January lows of −5°C, July highs of 31°C, 1,270 mm of precipitation a year.
- NOAA stationGrayville
- Station IDUSC00113612
- Location38.28°N 88.00°W
- Elevation435 ft (133 m)
- Population1,502
On October 22, the normal high in Grayville is 68°F and the normal low 44°F, and the chance of measurable rain or snow is 32%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Grayville.
- Jan 41° 24°
- Feb 45° 26°
- Mar 56° 35°
- Apr 68° 45°
- May 78° 55°
- Jun 86° 65°
- Jul 89° 68°
- Aug 88° 65°
- Sep 82° 57°
- Oct 70° 46°
- Nov 56° 36°
- Dec 45° 28°
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 Grayville each month?
July is the warmest month, with normal highs of 89°F; January the coldest, with normal lows of 24°F. The most precipitation falls in May (5.75 in), the least in January (3.22 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 41°F | 24°F | 32.4°F | 3.22 | 2.3 | 11 | <1 | 25 | 9 h 50 min |
| February | 45°F | 26°F | 35.4°F | 3.80 | 4.6 | 11 | <1 | 22 | 10 h 50 min |
| March | 56°F | 35°F | 45.3°F | 4.59 | 0.2 | 13 | <1 | 13 | 11 h 50 min |
| April | 68°F | 45°F | 56.2°F | 4.52 | 0.0 | 11 | <1 | 2 | 13 h 10 min |
| May | 78°F | 55°F | 66.3°F | 5.75 | 0.0 | 13 | 2 | <1 | 14 h 10 min |
| June | 86°F | 65°F | 75.1°F | 4.46 | 0.0 | 10 | 10 | <1 | 14 h 50 min |
| July | 89°F | 68°F | 78.1°F | 5.28 | 0.0 | 11 | 15 | <1 | 14 h 40 min |
| August | 88°F | 65°F | 76.2°F | 3.64 | 0.0 | 9 | 13 | <1 | 13 h 40 min |
| September | 82°F | 57°F | 69.8°F | 3.72 | 0.0 | 8 | 5 | <1 | 12 h 30 min |
| October | 70°F | 46°F | 57.8°F | 3.90 | 0.0 | 10 | 1 | 2 | 11 h 20 min |
| November | 56°F | 36°F | 46.0°F | 3.35 | 0.0 | 10 | <1 | 10 | 10 h 10 min |
| December | 45°F | 28°F | 36.2°F | 3.77 | 4.7 | 14 | <1 | 23 | 9 h 30 min |
| Year (annual) | 67°F | 46°F | 56.2°F | 50.00 | 11.8 | 130 | 46 | 97 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 5°C | −5°C | 0.2°C | 82 mm | 6 cm |
| February | 7°C | −3°C | 1.9°C | 97 mm | 12 cm |
| March | 13°C | 2°C | 7.4°C | 117 mm | 1 cm |
| April | 20°C | 7°C | 13.4°C | 115 mm | 0 cm |
| May | 25°C | 13°C | 19.1°C | 146 mm | 0 cm |
| June | 30°C | 18°C | 23.9°C | 113 mm | 0 cm |
| July | 31°C | 20°C | 25.6°C | 134 mm | 0 cm |
| August | 31°C | 18°C | 24.6°C | 92 mm | 0 cm |
| September | 28°C | 14°C | 21.0°C | 94 mm | 0 cm |
| October | 21°C | 8°C | 14.3°C | 99 mm | 0 cm |
| November | 13°C | 2°C | 7.8°C | 85 mm | 0 cm |
| December | 7°C | −2°C | 2.3°C | 96 mm | 12 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00113612; 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 Grayville?
Normal highs sit between 65°F and 85°F in April, May, September and October. 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 USC00113612.
When is the last frost in Grayville?
In Grayville, the last spring frost (32°F) comes after April 7 in half of years and after April 23 in one year in ten; the first autumn frost comes before October 25 in half of years and before October 12 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 71 year in 10 after April 23; 9 in 10 after March 24
- First autumn frost, half of years before
- October 251 year in 10 before October 12; 9 in 10 before November 7
NOAA puts the median frost-free season at 201 days, and the season without a hard freeze (28°F) at 223 days.
A hard freeze (28°F) comes after March 28 in half of springs and before November 5 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Grayville in zone 7a in ZIP code 62844, 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 USC00113612; 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 Grayville?
In a normal year in Grayville, 46 days a year reach 90°F (3 of them 100°F or more), 97 nights fall to 32°F or colder and 130 days bring measurable precipitation.
- Days at 90°F or more
- 46a normal year
- Days at 100°F or more
- 3a normal year
- Nights at 32°F or colder
- 97a normal year
- Days that stay below freezing
- 18high of 32°F or less
- Days with 0.01 inch of precipitation
- 130a normal year
- Days with 1 inch of snow or more
- 5a normal year
Source: NOAA NCEI 1991-2020 annual normals, station USC00113612.
How sunny is Grayville?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Grayville, 4.1 kWh per square metre a day. August is the sunniest month (82%) and December the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 63% | 2.0 |
| February | 64% | 2.7 |
| March | 67% | 3.7 |
| April | 72% | 5.0 |
| May | 73% | 5.6 |
| June | 81% | 6.4 |
| July | 82% | 6.3 |
| August | 82% | 5.7 |
| September | 80% | 4.7 |
| October | 75% | 3.4 |
| November | 71% | 2.4 |
| December | 62% | 1.7 |
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 Grayville need?
A normal year in Grayville brings 4,584 heating degree days, 15% fewer than the median U.S. place (5,373), and 1,424 cooling degree days, 57% more than the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,206 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,010 | 0 |
| February | 829 | 0 |
| March | 616 | 5 |
| April | 291 | 27 |
| May | 79 | 121 |
| June | 5 | 308 |
| July | 0 | 406 |
| August | 1 | 348 |
| September | 36 | 178 |
| October | 253 | 30 |
| November | 571 | 1 |
| December | 893 | 0 |
| Year (annual) | 4,584 | 1,424 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00113612. 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 Grayville's climate compare?
Grayville is warmer than 131 of the other 143 places with their own NOAA record in Illinois, and wetter than 134. Across the 7,247 U.S. stations with normals, its annual mean of 56.2°F is warmer than 64%.
In the Köppen classification computed from these normals, Grayville is Cfa: temperate, 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 Grayville share this climate record?
7 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.
- Poseyville, IN968 people · 14 mi SE
- Wadesville, IN778 people · 16 mi SE
- New Harmony, IN686 people · 11 mi S
- Crossville, IL601 people · 9 mi SW
- Stewartsville, IN184 people · 11 mi SE
- Blairsville, IN162 people · 19 mi SE
- Griffin, IN142 people · 7 mi SE
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 Grayville's climate
What is the coldest month in Grayville?
January, with a normal high of 41°F and a normal low of 24°F. The warmest is July (89°F by day, 68°F at night).
Does it snow in Grayville?
Yes: 12 inches in a normal year, falling on 8 days with 0.1 inch or more, the most in December (4.7 inches).
What is the rainiest month in Grayville?
May, with 5.75 in of precipitation in a normal year; the driest is January with 3.22 in.
What plant hardiness zone is Grayville in?
The USDA's 2023 map puts Grayville in zone 7a in ZIP code 62844, the nearest ZIP area.
How late can frost come in Grayville?
In half of years the last 32°F night comes after April 7; in one year in ten it comes after April 23. Waiting until April 23 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Illinois climateThe statewide normals and every place in the state
- Albion, IL7 miles from this station, 56.6°F a year
- Mount Carmel, IL16 miles from this station, 56.4°F a year
- Carmi, IL17 miles from this station, 55.0°F a year
- Fairfield, IL19 miles from this station, 57.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made