Sparta, Illinois climate: Normal weather by month, frost dates and records
Sparta's normal year runs from 22°F January nights to 88°F July afternoons, with 45.6 inches of precipitation and 11 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.8°C, January lows of −6°C, July highs of 31°C, 1,159 mm of precipitation a year.
- NOAA stationSparta (1 mi W)
- Station IDUSC00118147
- Location38.12°N 89.72°W
- Elevation535 ft (163 m)
- From the center2 miles
- Population4,040
On October 23, the normal high in Sparta is 67°F and the normal low 42°F, and the chance of measurable rain or snow is 29%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Sparta.
- Jan 40° 22°
- Feb 45° 25°
- Mar 56° 33°
- Apr 67° 43°
- May 76° 54°
- Jun 84° 62°
- Jul 88° 66°
- Aug 87° 64°
- Sep 81° 55°
- Oct 70° 44°
- Nov 56° 35°
- Dec 44° 26°
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 Sparta each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 22°F. The most precipitation falls in May (5.17 in), the least in February (2.57 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 40°F | 22°F | 30.9°F | 3.11 | 3.5 | 8 | <1 | 26 | 9 h 50 min |
| February | 45°F | 25°F | 35.2°F | 2.57 | 3.4 | 7 | <1 | 21 | 10 h 50 min |
| March | 56°F | 33°F | 44.3°F | 3.95 | 0.6 | 10 | <1 | 16 | 11 h 50 min |
| April | 67°F | 43°F | 55.0°F | 5.16 | 0.0 | 10 | <1 | 5 | 13 h 10 min |
| May | 76°F | 54°F | 64.9°F | 5.17 | 0.0 | 10 | 1 | <1 | 14 h 10 min |
| June | 84°F | 62°F | 73.3°F | 4.31 | 0.0 | 9 | 7 | <1 | 14 h 50 min |
| July | 88°F | 66°F | 76.7°F | 4.68 | 0.0 | 8 | 13 | <1 | 14 h 40 min |
| August | 87°F | 64°F | 75.2°F | 3.54 | 0.0 | 8 | 10 | <1 | 13 h 40 min |
| September | 81°F | 55°F | 68.1°F | 3.03 | 0.0 | 7 | 4 | <1 | 12 h 30 min |
| October | 70°F | 44°F | 57.0°F | 3.34 | 0.0 | 7 | <1 | 4 | 11 h 20 min |
| November | 56°F | 35°F | 45.2°F | 4.08 | 0.5 | 9 | <1 | 14 | 10 h 10 min |
| December | 44°F | 26°F | 35.0°F | 2.70 | 2.6 | 8 | <1 | 23 | 9 h 30 min |
| Year (annual) | 66°F | 44°F | 55.1°F | 45.64 | 10.6 | 103 | 35 | 109 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 5°C | −6°C | −0.6°C | 79 mm | 9 cm |
| February | 7°C | −4°C | 1.8°C | 65 mm | 9 cm |
| March | 13°C | 1°C | 6.8°C | 100 mm | 2 cm |
| April | 19°C | 6°C | 12.8°C | 131 mm | 0 cm |
| May | 24°C | 12°C | 18.3°C | 131 mm | 0 cm |
| June | 29°C | 17°C | 22.9°C | 109 mm | 0 cm |
| July | 31°C | 19°C | 24.8°C | 119 mm | 0 cm |
| August | 30°C | 18°C | 24.0°C | 90 mm | 0 cm |
| September | 27°C | 13°C | 20.1°C | 77 mm | 0 cm |
| October | 21°C | 7°C | 13.9°C | 85 mm | 0 cm |
| November | 13°C | 1°C | 7.3°C | 104 mm | 1 cm |
| December | 7°C | −3°C | 1.7°C | 69 mm | 7 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00118147; 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 Sparta?
Normal highs sit between 65°F and 85°F in April, May, June, September and October. 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 USC00118147.
When is the last frost in Sparta?
In Sparta, the last spring frost (32°F) comes after April 12 in half of years and after April 29 in one year in ten; the first autumn frost comes before October 22 in half of years and before October 7 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 121 year in 10 after April 29; 9 in 10 after March 29
- First autumn frost, half of years before
- October 221 year in 10 before October 7; 9 in 10 before November 2
NOAA puts the median frost-free season at 191 days, and the season without a hard freeze (28°F) at 213 days.
A hard freeze (28°F) comes after April 1 in half of springs and before November 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Sparta in zone 7a in ZIP code 62286. By the map's own method, the average of each year's coldest night over 1991-2020, Sparta's NOAA station is in zone 6b: the coldest night of a typical year reaches 0°F (17 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Illinois · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00118147; 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 Sparta?
In a normal year in Sparta, 35 days a year reach 90°F (1 of them 100°F or more), 109 nights fall to 32°F or colder and 103 days bring measurable precipitation.
- Days at 90°F or more
- 35a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 109a normal year
- Days that stay below freezing
- 19high of 32°F or less
- Days with 0.01 inch of precipitation
- 103a normal year
- Days with 1 inch of snow or more
- 4a normal year
The highest temperature in this station's record (since 1893) is 114°F, on July 24, 1934; the lowest is −23°F, on February 12, 1899.
The wettest calendar year on that record is 1949, with 62.59 in; the snowiest season is 1911–12, with 60.7 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00118147; records: ACIS (NOAA Regional Climate Centers), station USC00118147. Records use complete months only; a month missing more than three days is left out.
How sunny is Sparta?
Over a year 75% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Sparta, 4.2 kWh per square metre a day. August is the sunniest month (83%) and December the cloudiest (64%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 66% | 2.1 |
| February | 66% | 2.8 |
| March | 67% | 3.8 |
| April | 73% | 5.0 |
| May | 74% | 5.6 |
| June | 81% | 6.5 |
| July | 83% | 6.3 |
| August | 83% | 5.7 |
| September | 81% | 4.8 |
| October | 76% | 3.4 |
| November | 72% | 2.4 |
| December | 64% | 1.8 |
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 Sparta need?
A normal year in Sparta brings 4,833 heating degree days, 10% fewer than the median U.S. place (5,373), and 1,244 cooling degree days, 37% more than the median (908). Six months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 3,944 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,058 | 0 |
| February | 836 | 0 |
| March | 644 | 4 |
| April | 319 | 19 |
| May | 104 | 101 |
| June | 9 | 260 |
| July | 1 | 362 |
| August | 3 | 319 |
| September | 57 | 149 |
| October | 275 | 28 |
| November | 598 | 3 |
| December | 930 | 0 |
| Year (annual) | 4,833 | 1,244 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00118147. 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 Sparta's climate compare?
Sparta is warmer than 122 of the other 143 places with their own NOAA record in Illinois, and wetter than 120. Across the 7,247 U.S. stations with normals, its annual mean of 55.1°F is warmer than 61%.
In the Köppen classification computed from these normals, Sparta 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 Sparta share this climate record?
10 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.
- Steeleville, IL1,895 people · 8 mi S
- Marissa, IL1,743 people · 10 mi N
- Percy, IL907 people · 9 mi SE
- Coulterville, IL826 people · 8 mi NE
- Tilden, IL750 people · 7 mi N
- Willisville, IL559 people · 12 mi SE
- Lenzburg, IL448 people · 13 mi NW
- Cutler, IL355 people · 10 mi SE
- Baldwin, IL315 people · 8 mi NW
- Darmstadt, IL0 people · 14 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 Sparta's climate
What is the coldest month in Sparta?
January, with a normal high of 40°F and a normal low of 22°F. The warmest is July (88°F by day, 66°F at night).
Does it snow in Sparta?
Yes: 11 inches in a normal year, falling on 7 days with 0.1 inch or more, the most in January (3.5 inches).
What is the rainiest month in Sparta?
May, with 5.17 in of precipitation in a normal year; the driest is February with 2.57 in.
What plant hardiness zone is Sparta in?
The USDA's 2023 map puts Sparta in zone 7a in ZIP code 62286. By the same method at Sparta's NOAA station, the coldest night of a typical year reaches 0°F (17 years, 1991-2020): zone 6b.
How late can frost come in Sparta?
In half of years the last 32°F night comes after April 12; in one year in ten it comes after April 29. Waiting until April 29 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Illinois climateThe statewide normals and every place in the state
- Kaskaskia, IL16 miles from this station, 56.4°F a year
- Nashville, IL25 miles from this station, 55.1°F a year
- Perryville, MO29 miles from this station, 55.0°F a year
- Belleville, IL29 miles from this station, 57.7°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made