Sidell, Illinois climate: Normal weather by month, frost dates and records
Sidell's normal year runs from 17°F January nights to 84°F July afternoons, with 40.4 inches of precipitation and 24 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.8°C, January lows of −8°C, July highs of 29°C, 1,026 mm of precipitation a year.
- NOAA stationSidell (4 mi N)
- Station IDUSC00117952
- Location39.97°N 87.82°W
- Elevation672 ft (205 m)
- From the center4 miles
- Population467
On October 23, the normal high in Sidell is 62°F and the normal low 40°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 Sidell.
- Jan 33° 17°
- Feb 37° 20°
- Mar 49° 30°
- Apr 62° 41°
- May 73° 53°
- Jun 82° 62°
- Jul 84° 64°
- Aug 83° 62°
- Sep 78° 54°
- Oct 65° 43°
- Nov 50° 32°
- Dec 38° 23°
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 Sidell each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 17°F. The most precipitation falls in July (4.72 in), the least in February (2.00 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 33°F | 17°F | 24.9°F | 2.35 | 7.1 | 10 | <1 | 28 | 9 h 40 min |
| February | 37°F | 20°F | 28.8°F | 2.00 | 6.7 | 10 | <1 | 25 | 10 h 40 min |
| March | 49°F | 30°F | 39.7°F | 2.77 | 2.4 | 11 | <1 | 18 | 11 h 50 min |
| April | 62°F | 41°F | 51.5°F | 4.15 | 0.4 | 12 | <1 | 7 | 13 h 10 min |
| May | 73°F | 53°F | 63.1°F | 4.66 | 0.0 | 12 | 1 | <1 | 14 h 20 min |
| June | 82°F | 62°F | 72.1°F | 4.61 | 0.0 | 11 | 6 | <1 | 15 h |
| July | 84°F | 64°F | 74.1°F | 4.72 | 0.0 | 9 | 8 | <1 | 14 h 50 min |
| August | 83°F | 62°F | 72.3°F | 3.25 | 0.0 | 8 | 5 | <1 | 13 h 50 min |
| September | 78°F | 54°F | 66.1°F | 2.73 | 0.0 | 8 | 4 | <1 | 12 h 30 min |
| October | 65°F | 43°F | 54.1°F | 3.33 | 0.0 | 9 | <1 | 5 | 11 h 10 min |
| November | 50°F | 32°F | 41.1°F | 3.34 | 1.1 | 11 | <1 | 17 | 10 h |
| December | 38°F | 23°F | 30.5°F | 2.48 | 6.0 | 11 | <1 | 26 | 9 h 20 min |
| Year (annual) | 61°F | 42°F | 51.5°F | 40.39 | 23.7 | 122 | 23 | 126 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −8°C | −3.9°C | 60 mm | 18 cm |
| February | 3°C | −6°C | −1.8°C | 51 mm | 17 cm |
| March | 10°C | −1°C | 4.3°C | 70 mm | 6 cm |
| April | 17°C | 5°C | 10.8°C | 105 mm | 1 cm |
| May | 23°C | 12°C | 17.3°C | 118 mm | 0 cm |
| June | 28°C | 17°C | 22.3°C | 117 mm | 0 cm |
| July | 29°C | 18°C | 23.4°C | 120 mm | 0 cm |
| August | 28°C | 16°C | 22.4°C | 83 mm | 0 cm |
| September | 26°C | 12°C | 18.9°C | 69 mm | 0 cm |
| October | 19°C | 6°C | 12.3°C | 85 mm | 0 cm |
| November | 10°C | 0°C | 5.1°C | 85 mm | 3 cm |
| December | 3°C | −5°C | −0.8°C | 63 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00117952; 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 Sidell?
Normal highs sit between 65°F and 85°F in May, June, July, August, 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 USC00117952.
When is the last frost in Sidell?
In Sidell, the last spring frost (32°F) comes after April 19 in half of years and after May 3 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 191 year in 10 after May 3; 9 in 10 after April 4
- First autumn frost, half of years before
- October 191 year in 10 before October 5; 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 6 in half of springs and before October 30 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sidell in zone 6a in ZIP code 61876, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Sidell's NOAA station is in zone 6a: the coldest night of a typical year reaches −9°F (16 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 USC00117952; 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 Sidell?
In a normal year in Sidell, 23 days a year reach 90°F, 126 nights fall to 32°F or colder and 122 days bring measurable precipitation.
- Days at 90°F or more
- 23a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 126a normal year
- Days that stay below freezing
- 38high of 32°F or less
- Days with 0.01 inch of precipitation
- 122a normal year
- Days with 1 inch of snow or more
- 8a normal year
The highest temperature in this station's record (since 2000) is 102°F, on July 8, 2012; the lowest is −17°F, on January 17, 2009.
The wettest calendar year on that record is 2008, with 53.36 in; the snowiest season is 1977–78, with 45.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00117952; records: ACIS (NOAA Regional Climate Centers), station USC00117952. Records use complete months only; a month missing more than three days is left out.
How sunny is Sidell?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Sidell, 4.0 kWh per square metre a day. August is the sunniest month (82%) and December the cloudiest (60%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 61% | 1.8 |
| February | 64% | 2.6 |
| March | 67% | 3.7 |
| April | 71% | 4.9 |
| May | 73% | 5.5 |
| June | 80% | 6.3 |
| July | 81% | 6.2 |
| August | 82% | 5.6 |
| September | 81% | 4.7 |
| October | 74% | 3.3 |
| November | 70% | 2.2 |
| December | 60% | 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 Sidell need?
A normal year in Sidell brings 5,854 heating degree days, 9% more than the median U.S. place (5,373), and 975 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 3,411 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,243 | 0 |
| February | 1,015 | 0 |
| March | 788 | 2 |
| April | 415 | 9 |
| May | 147 | 86 |
| June | 14 | 227 |
| July | 3 | 286 |
| August | 8 | 236 |
| September | 77 | 109 |
| October | 358 | 20 |
| November | 718 | 1 |
| December | 1,069 | 0 |
| Year (annual) | 5,854 | 975 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00117952. 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 Sidell been warmer than normal lately?
2025 averaged 54.9°F, 3.4°F above the 1991-2020 normal of 51.5°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 52.4°F | +0.9°F | 43.15 | 22.2 |
| 2022 | 51.0°F | −0.5°F | 31.77 | 21.3 |
| 2023 | 55.3°F | +3.8°F | 32.00 | 9.3 |
| 2024 | 56.1°F | +4.6°F | 36.76 | 13.9 |
| 2025 | 54.9°F | +3.4°F | 25.33 | 30.3 |
Source: observed years: ACIS, station USC00117952. A year counts only with all twelve months complete.
How does Sidell's climate compare?
Sidell is warmer than 66 of the other 143 places with their own NOAA record in Illinois, and wetter than 78. Across the 7,247 U.S. stations with normals, its annual mean of 51.5°F is warmer than 47%.
In the Köppen classification computed from these normals, Sidell 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 Sidell 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.
- Newman, IL773 people · 15 mi SW
- Fairmount, IL589 people · 5 mi N
- Hume, IL313 people · 12 mi S
- Broadlands, IL312 people · 10 mi SW
- Allerton, IL253 people · 7 mi SW
- Indianola, IL219 people · 5 mi SE
- Metcalf, IL134 people · 12 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 Sidell's climate
What is the coldest month in Sidell?
January, with a normal high of 33°F and a normal low of 17°F. The warmest is July (84°F by day, 64°F at night).
Does it snow in Sidell?
Yes: 24 inches in a normal year, falling on 18 days with 0.1 inch or more, the most in January (7.1 inches).
What is the rainiest month in Sidell?
July, with 4.72 in of precipitation in a normal year; the driest is February with 2.00 in.
What plant hardiness zone is Sidell in?
The USDA's 2023 map puts Sidell in zone 6a in ZIP code 61876, the nearest ZIP area. By the same method at Sidell's NOAA station, the coldest night of a typical year reaches −9°F (16 years, 1991-2020): zone 6a.
How late can frost come in Sidell?
In half of years the last 32°F night comes after April 19; in one year in ten it comes after May 3. Waiting until May 3 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Illinois climateThe statewide normals and every place in the state
- Ogden, IL12 miles from this station, 52.2°F a year
- Danville, IL15 miles from this station, 53.1°F a year
- Perrysville, IN18 miles from this station, 52.2°F a year
- Champaign, IL25 miles from this station, 52.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made