Effingham, Illinois climate: Normal weather by month, frost dates and records
Effingham's normal year runs from 20°F January nights to 89°F July afternoons, with 44.0 inches of precipitation and 15 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 12.4°C, January lows of −7°C, July highs of 31°C, 1,118 mm of precipitation a year.
- NOAA stationEffingham (3 mi SW)
- Station IDUSC00112687
- Location39.12°N 88.62°W
- Elevation625 ft (191 m)
- From the center4 miles
- Population12,434
On October 23, the normal high in Effingham is 66°F and the normal low 42°F, and the chance of measurable rain or snow is 31%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Effingham.
- Jan 37° 20°
- Feb 43° 23°
- Mar 54° 32°
- Apr 66° 42°
- May 76° 54°
- Jun 85° 63°
- Jul 89° 66°
- Aug 87° 64°
- Sep 81° 56°
- Oct 69° 44°
- Nov 54° 34°
- Dec 42° 25°
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 Effingham each month?
July is the warmest month, with normal highs of 89°F; January the coldest, with normal lows of 20°F. The most precipitation falls in May (5.27 in), the least in February (2.44 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 37°F | 20°F | 28.8°F | 2.93 | 5.3 | 9 | <1 | 27 | 9 h 40 min |
| February | 43°F | 23°F | 33.0°F | 2.44 | 4.6 | 9 | <1 | 23 | 10 h 40 min |
| March | 54°F | 32°F | 42.9°F | 3.30 | 1.5 | 11 | <1 | 17 | 11 h 50 min |
| April | 66°F | 42°F | 54.2°F | 4.84 | 0.2 | 11 | <1 | 4 | 13 h 10 min |
| May | 76°F | 54°F | 64.9°F | 5.27 | 0.0 | 12 | 1 | <1 | 14 h 20 min |
| June | 85°F | 63°F | 74.0°F | 4.87 | 0.0 | 11 | 8 | <1 | 14 h 50 min |
| July | 89°F | 66°F | 77.2°F | 4.29 | 0.0 | 9 | 13 | <1 | 14 h 40 min |
| August | 87°F | 64°F | 75.4°F | 3.19 | 0.0 | 8 | 10 | <1 | 13 h 40 min |
| September | 81°F | 56°F | 68.4°F | 2.89 | 0.0 | 8 | 5 | <1 | 12 h 30 min |
| October | 69°F | 44°F | 56.4°F | 3.49 | 0.0 | 9 | 1 | 4 | 11 h 10 min |
| November | 54°F | 34°F | 43.9°F | 3.73 | 0.6 | 10 | <1 | 15 | 10 h |
| December | 42°F | 25°F | 33.8°F | 2.77 | 2.4 | 10 | <1 | 24 | 9 h 30 min |
| Year (annual) | 65°F | 44°F | 54.4°F | 44.01 | 14.6 | 116 | 38 | 114 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −7°C | −1.8°C | 74 mm | 13 cm |
| February | 6°C | −5°C | 0.6°C | 62 mm | 12 cm |
| March | 12°C | 0°C | 6.1°C | 84 mm | 4 cm |
| April | 19°C | 6°C | 12.3°C | 123 mm | 1 cm |
| May | 25°C | 12°C | 18.3°C | 134 mm | 0 cm |
| June | 30°C | 17°C | 23.3°C | 124 mm | 0 cm |
| July | 31°C | 19°C | 25.1°C | 109 mm | 0 cm |
| August | 31°C | 18°C | 24.1°C | 81 mm | 0 cm |
| September | 27°C | 13°C | 20.2°C | 73 mm | 0 cm |
| October | 20°C | 7°C | 13.6°C | 89 mm | 0 cm |
| November | 12°C | 1°C | 6.6°C | 95 mm | 2 cm |
| December | 6°C | −4°C | 1.0°C | 70 mm | 6 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00112687; 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 Effingham?
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 USC00112687.
When is the last frost in Effingham?
In Effingham, the last spring frost (32°F) comes after April 13 in half of years and after April 29 in one year in ten; the first autumn frost comes before October 24 in half of years and before October 9 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 131 year in 10 after April 29; 9 in 10 after April 1
- First autumn frost, half of years before
- October 241 year in 10 before October 9; 9 in 10 before November 5
NOAA puts the median frost-free season at 191 days, and the season without a hard freeze (28°F) at 214 days.
A hard freeze (28°F) comes after April 2 in half of springs and before November 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Effingham in zone 6b in ZIP code 62401, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Effingham's NOAA station is in zone 6b: the coldest night of a typical year reaches −5°F (25 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 USC00112687; 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 Effingham?
In a normal year in Effingham, 38 days a year reach 90°F (1 of them 100°F or more), 114 nights fall to 32°F or colder and 116 days bring measurable precipitation.
- Days at 90°F or more
- 38a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 114a normal year
- Days that stay below freezing
- 26high of 32°F or less
- Days with 0.01 inch of precipitation
- 116a normal year
- Days with 1 inch of snow or more
- 6a normal year
The highest temperature in this station's record (since 1892) is 111°F, on July 15, 1936; the lowest is −29°F, on January 24, 1915.
The wettest calendar year on that record is 1993, with 59.69 in; the snowiest season is 1977–78, with 40.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00112687; records: ACIS (NOAA Regional Climate Centers), station USC00112687. Records use complete months only; a month missing more than three days is left out.
How sunny is Effingham?
Over a year 74% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Effingham, 4.1 kWh per square metre a day. July is the sunniest month (83%) and December the cloudiest (61%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 62% | 1.9 |
| February | 65% | 2.7 |
| March | 67% | 3.7 |
| April | 72% | 4.9 |
| May | 73% | 5.5 |
| June | 81% | 6.4 |
| July | 83% | 6.3 |
| August | 82% | 5.6 |
| September | 81% | 4.7 |
| October | 74% | 3.3 |
| November | 70% | 2.3 |
| December | 61% | 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 Effingham need?
A normal year in Effingham brings 5,126 heating degree days, 5% fewer than the median U.S. place (5,373), and 1,298 cooling degree days, 43% 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 3,936 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,124 | 0 |
| February | 898 | 0 |
| March | 686 | 2 |
| April | 342 | 16 |
| May | 109 | 106 |
| June | 10 | 279 |
| July | 1 | 380 |
| August | 2 | 326 |
| September | 56 | 156 |
| October | 296 | 31 |
| November | 636 | 2 |
| December | 967 | 0 |
| Year (annual) | 5,126 | 1,298 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00112687. 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 Effingham been warmer than normal lately?
Over 80 complete years from 1897 to 2019, the station's annual mean temperature rose at a fitted 0.8°F per century (+0.04°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Effingham's climate compare?
Effingham is warmer than 112 of the other 143 places with their own NOAA record in Illinois, and wetter than 114. Across the 7,247 U.S. stations with normals, its annual mean of 54.4°F is warmer than 58%.
In the Köppen classification computed from these normals, Effingham 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 Effingham share this climate record?
8 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.
- Altamont, IL2,200 people · 8 mi SW
- Teutopolis, IL1,694 people · 8 mi E
- Watson, IL657 people · 7 mi SE
- Beecher City, IL423 people · 10 mi NW
- Edgewood, IL392 people · 14 mi S
- Mason, IL321 people · 11 mi S
- Montrose, IL216 people · 14 mi E
- Shumway, IL186 people · 5 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 Effingham's climate
What is the coldest month in Effingham?
January, with a normal high of 37°F and a normal low of 20°F. The warmest is July (89°F by day, 66°F at night).
Does it snow in Effingham?
Yes: 15 inches in a normal year, falling on 9 days with 0.1 inch or more, the most in January (5.3 inches).
What is the rainiest month in Effingham?
May, with 5.27 in of precipitation in a normal year; the driest is February with 2.44 in.
What plant hardiness zone is Effingham in?
The USDA's 2023 map puts Effingham in zone 6b in ZIP code 62401, the nearest ZIP area. By the same method at Effingham's NOAA station, the coldest night of a typical year reaches −5°F (25 years, 1991-2020): zone 6b.
How late can frost come in Effingham?
In half of years the last 32°F night comes after April 13; 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
- Effingham in OctoberThis month day by day, its records and recent years
- Illinois climateThe statewide normals and every place in the state
- Neoga, IL17 miles from this station, 53.6°F a year
- Brownstown, IL21 miles from this station, 54.6°F a year
- Shelbyville, IL22 miles from this station, 53.6°F a year
- Windsor, IL23 miles from this station, 52.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made