Marseilles, Illinois climate: Normal weather by month, frost dates and records
Marseilles's normal year runs from 14°F January nights to 84°F July afternoons, with 39.0 inches of precipitation and 25 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.8°C, January lows of −10°C, July highs of 29°C, 991 mm of precipitation a year.
- NOAA stationMarseilles Lock
- Station IDUSC00115372
- Location41.33°N 88.75°W
- Elevation490 ft (149 m)
- Population4,779
On October 14, the normal high in Marseilles is 65°F and the normal low 42°F, and the chance of measurable rain or snow is 30%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Marseilles.
- Jan 31° 14°
- Feb 35° 17°
- Mar 48° 27°
- Apr 61° 37°
- May 73° 49°
- Jun 81° 58°
- Jul 84° 62°
- Aug 82° 61°
- Sep 77° 53°
- Oct 64° 41°
- Nov 49° 30°
- Dec 37° 21°
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 Marseilles each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 14°F. The most precipitation falls in June (4.92 in), the least in February (1.90 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 31°F | 14°F | 22.8°F | 1.95 | 8.4 | 11 | <1 | 29 | 9 h 30 min |
| February | 35°F | 17°F | 26.3°F | 1.90 | 7.3 | 10 | <1 | 25 | 10 h 40 min |
| March | 48°F | 27°F | 37.3°F | 2.54 | 2.9 | 11 | <1 | 23 | 11 h 50 min |
| April | 61°F | 37°F | 49.2°F | 3.59 | 0.3 | 12 | <1 | 9 | 13 h 20 min |
| May | 73°F | 49°F | 60.5°F | 4.70 | 0.0 | 12 | 1 | 1 | 14 h 30 min |
| June | 81°F | 58°F | 69.6°F | 4.92 | 0.0 | 11 | 3 | <1 | 15 h 10 min |
| July | 84°F | 62°F | 73.0°F | 3.85 | 0.0 | 9 | 5 | <1 | 14 h 50 min |
| August | 82°F | 61°F | 71.5°F | 4.09 | 0.0 | 9 | 3 | <1 | 13 h 50 min |
| September | 77°F | 53°F | 65.0°F | 3.46 | 0.0 | 8 | 2 | <1 | 12 h 30 min |
| October | 64°F | 41°F | 52.7°F | 3.20 | 0.0 | 10 | <1 | 6 | 11 h 10 min |
| November | 49°F | 30°F | 39.6°F | 2.72 | 0.8 | 10 | <1 | 18 | 9 h 50 min |
| December | 37°F | 21°F | 28.5°F | 2.11 | 5.3 | 11 | <1 | 27 | 9 h 10 min |
| Year (annual) | 60°F | 39°F | 49.7°F | 39.03 | 25.0 | 124 | 14 | 139 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 0°C | −10°C | −5.1°C | 50 mm | 21 cm |
| February | 2°C | −8°C | −3.2°C | 48 mm | 19 cm |
| March | 9°C | −3°C | 2.9°C | 65 mm | 7 cm |
| April | 16°C | 3°C | 9.6°C | 91 mm | 1 cm |
| May | 23°C | 9°C | 15.8°C | 119 mm | 0 cm |
| June | 27°C | 15°C | 20.9°C | 125 mm | 0 cm |
| July | 29°C | 17°C | 22.8°C | 98 mm | 0 cm |
| August | 28°C | 16°C | 21.9°C | 104 mm | 0 cm |
| September | 25°C | 12°C | 18.3°C | 88 mm | 0 cm |
| October | 18°C | 5°C | 11.5°C | 81 mm | 0 cm |
| November | 10°C | −1°C | 4.2°C | 69 mm | 2 cm |
| December | 3°C | −6°C | −1.9°C | 54 mm | 13 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00115372; 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 Marseilles?
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 (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 USC00115372.
When is the last frost in Marseilles?
In Marseilles, the last spring frost (32°F) comes after April 27 in half of years and after May 13 in one year in ten; the first autumn frost comes before October 17 in half of years and before October 3 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 271 year in 10 after May 13; 9 in 10 after April 12
- First autumn frost, half of years before
- October 171 year in 10 before October 3; 9 in 10 before October 29
NOAA puts the median frost-free season at 171 days, and the season without a hard freeze (28°F) at 194 days.
A hard freeze (28°F) comes after April 15 in half of springs and before October 27 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Marseilles in zone 5b in ZIP code 61341, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Marseilles's NOAA station is in zone 5b: the coldest night of a typical year reaches −12°F (22 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 USC00115372; 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 Marseilles?
In a normal year in Marseilles, 14 days a year reach 90°F, 139 nights fall to 32°F or colder and 124 days bring measurable precipitation.
- Days at 90°F or more
- 14a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 139a normal year
- Days that stay below freezing
- 43high of 32°F or less
- Days with 0.01 inch of precipitation
- 124a normal year
- Days with 1 inch of snow or more
- 10a normal year
The highest temperature in this station's record (since 1949) is 102°F, on July 25, 2005; the lowest is −27°F, on January 5, 1999.
The wettest calendar year on that record is 2009, with 51.14 in; the snowiest season is 1978–79, with 68.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00115372; records: ACIS (NOAA Regional Climate Centers), station USC00115372. Records use complete months only; a month missing more than three days is left out.
How sunny is Marseilles?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Marseilles, 3.9 kWh per square metre a day. July is the sunniest month (81%) and January the cloudiest (61%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 61% | 1.7 |
| February | 65% | 2.6 |
| March | 67% | 3.6 |
| April | 70% | 4.8 |
| May | 71% | 5.5 |
| June | 77% | 6.1 |
| July | 81% | 6.2 |
| August | 80% | 5.4 |
| September | 80% | 4.5 |
| October | 71% | 3.0 |
| November | 67% | 2.0 |
| December | 61% | 1.5 |
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 Marseilles need?
A normal year in Marseilles brings 6,351 heating degree days, 18% more than the median U.S. place (5,373), and 800 cooling degree days, 12% 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 3,084 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,308 | 0 |
| February | 1,083 | 0 |
| March | 859 | 2 |
| April | 478 | 6 |
| May | 195 | 57 |
| June | 30 | 168 |
| July | 5 | 251 |
| August | 8 | 208 |
| September | 94 | 94 |
| October | 398 | 15 |
| November | 764 | 0 |
| December | 1,130 | 0 |
| Year (annual) | 6,351 | 800 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00115372. 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 Marseilles been warmer than normal lately?
2025 averaged 51.3°F, 1.6°F above the 1991-2020 normal of 49.7°F. 3 of the 3 complete years since 2023 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2023 | 51.4°F | +1.7°F | 36.53 | 10.6 |
| 2024 | 53.0°F | +3.3°F | 35.04 | 12.2 |
| 2025 | 51.3°F | +1.6°F | 29.75 | 23.2 |
Source: observed years: ACIS, station USC00115372. A year counts only with all twelve months complete.
How does Marseilles's climate compare?
Marseilles is warmer than 31 of the other 143 places with their own NOAA record in Illinois, and wetter than 52. Across the 7,247 U.S. stations with normals, its annual mean of 49.7°F is warmer than 39%.
In the Köppen classification computed from these normals, Marseilles 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 Marseilles share this climate record?
6 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.
- Sheridan, IL2,413 people · 14 mi N
- Seneca, IL2,310 people · 7 mi E
- Grand Ridge, IL508 people · 8 mi SW
- Dayton, IL363 people · 5 mi NW
- Serena, IL195 people · 11 mi N
- Wedron, IL69 people · 8 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 Marseilles's climate
What is the coldest month in Marseilles?
January, with a normal high of 31°F and a normal low of 14°F. The warmest is July (84°F by day, 62°F at night).
Does it snow in Marseilles?
Yes: 25 inches in a normal year, falling on 17 days with 0.1 inch or more, the most in January (8.4 inches).
What is the rainiest month in Marseilles?
June, with 4.92 in of precipitation in a normal year; the driest is February with 1.90 in.
What plant hardiness zone is Marseilles in?
The USDA's 2023 map puts Marseilles in zone 5b in ZIP code 61341, the nearest ZIP area. By the same method at Marseilles's NOAA station, the coldest night of a typical year reaches −12°F (22 years, 1991-2020): zone 5b.
How late can frost come in Marseilles?
In half of years the last 32°F night comes after April 27; in one year in ten it comes after May 13. Waiting until May 13 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Illinois climateThe statewide normals and every place in the state
- Ottawa, IL8 miles from this station, 50.2°F a year
- Streator, IL17 miles from this station, 51.6°F a year
- Morris, IL17 miles from this station, 50.8°F a year
- Peru, IL19 miles from this station, 49.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made