Cahokia St Louis, IL Climate: Temperature & Rain by Month
Explore NOAA NCEI's 1991–2020 climate normals → and a clearly labeled PlainClimate comfort calculation
30-year climate normals (1991-2020) from Cahokia St Louis's primary NOAA station, CAHOKIA ST LOUIS AP.
The climate verdict for Cahokia St Louis
Cahokia St Louis, Illinois has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 57°F. It scores 80/100 for climate comfort (excellent), putting it in the top third of station-mapped location scores and exceeding 76% of them.
- 57°F
- yearly average temperature, NOAA normal
- 80/100
- comfort score, above 76% of station-mapped location scores
- 40.8"
- precipitation, annual total
- 201 days
- frost-free growing season
Cahokia St Louis: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00003960 · Cahokia St Louis, IL 57°F mean · 40.8" precip
TEMP-MILD · RANK-UPPER · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-TOP · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-MILD 57°F
- RANK-UPPER #4,460
- PHOTO-FINISH ≈ Parsons
- PRCP-MID 40.8"
- SWING-WIDE 47°F
- COMF-TOP 80/100
- LOAD-HEAT 4,547 HDD
- STN-1 USW00003960
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Parsons, KS (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every IL station list.
- Cahokia St Louis (this station) 57°F
- Hot Pomme De Terre…, MO 57°F
- Near Parsons, KS 57°F
- Near Lahontan Dam, NV 57°F
- Cold Mt Carmel, IL 56°F
Climate Living Index · Cahokia St Louis
Cahokia St Louis: 72/100 · grade B
Cahokia St Louis publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Cahokia St Louis, not an official NOAA rating. Rankings still use Comfort Score 80/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 40.8 in · 5.8 from 35 in | 79/100 · B |
| Normal heat + freeze calendar | 94 calendar days | 78/100 · B |
| Annual temperature balance | 56.5°F · 11.0° from 67.5°F | 65/100 · C |
| Frost-free season | 201 days/year | 65/100 · C |
Cahokia St Louis · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Cahokia St Louis is a temperate Köppen climate: Cfa
Coldest-month mean 32.1°F and warmest-month mean 78.9°F place this station in temperate, no dry season, hot summer climates (Cfa). Class Cfa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: temperate, specifically temperate, no dry season, hot summer.
- Köppen code
- Cfa
- Group
- Temperate
- Warmest month
- 78.9°F
- Coldest month
- 32.1°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Cahokia St Louis sits across the climate record
Three NOAA fields for Cahokia St Louis's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 65th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 60th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- 67th percentile swing
- Typical seasonal amplitude versus 6,861 complete station-years.
How Cahokia St Louis compares across U.S. station-mapped locations
Cahokia St Louis's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
80 Top 24% score exceeds 76% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). Below this entry.
- 70–80: 650 station-mapped locations (11%). Below this entry.
- 80–90: 921 station-mapped locations (15%). This entry sits in this band.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 40°F (5°C) | 24°F (-4°C) | 32°F (0°C) | 2.5" | 24.9 | 0.0 |
| February | 46°F (8°C) | 28°F (-2°C) | 37°F (3°C) | 2.0" | 20.9 | 0.0 |
| March | 56°F (13°C) | 36°F (2°C) | 46°F (8°C) | 3.3" | 12.4 | 0.0 |
| April | 68°F (20°C) | 46°F (8°C) | 57°F (14°C) | 4.5" | 2.6 | 0.2 |
| May | 77°F (25°C) | 57°F (14°C) | 67°F (19°C) | 4.8" | 0.0 | 1.8 |
| June | 86°F (30°C) | 65°F (18°C) | 75°F (24°C) | 4.4" | 0.0 | 10.1 |
| July | 89°F (32°C) | 69°F (20°C) | 79°F (26°C) | 3.7" | 0.0 | 15.9 |
| August | 88°F (31°C) | 66°F (19°C) | 77°F (25°C) | 3.7" | 0.0 | 12.0 |
| September | 81°F (27°C) | 57°F (14°C) | 69°F (21°C) | 3.4" | 0.0 | 5.5 |
| October | 69°F (21°C) | 46°F (8°C) | 58°F (14°C) | 3.1" | 2.6 | 0.5 |
| November | 55°F (13°C) | 36°F (2°C) | 46°F (8°C) | 3.3" | 12.6 | 0.0 |
| December | 44°F (7°C) | 29°F (-2°C) | 36°F (2°C) | 2.3" | 22.0 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 89°F around July 20, short of 90°F on every date, while 94 dates carry a normal low at or below freezing, the coldest 24°F near January 19.
The freezing stretch
The normal low stays at or below 32°F into March 2, then returns to freezing around November 30, covering 94 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is May 11, when 44% of years recorded at least a hundredth of an inch. The driest is January 12 at 25%. Summed across the calendar, that is about 117 wet dates a year.
The widest day
September 30 carries the biggest normal gap between afternoon and dawn, 24°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Cahokia St Louis.
Monthly Precipitation
Average monthly rainfall
7.8 days with precipitation
8.3 days with precipitation
10.9 days with precipitation
10.6 days with precipitation
13.9 days with precipitation
10.6 days with precipitation
9.6 days with precipitation
10.0 days with precipitation
9.1 days with precipitation
8.9 days with precipitation
8.5 days with precipitation
8.4 days with precipitation
Cahokia St Louis spreads its precipitation across the year
Neither half of the year dominates here: June through August take 29% of the annual total and December through February 17%, with neither reaching the 35% that would mark a distinct wet season. Cahokia St Louis has no dry season to plan around, though it does carry a wide 46.8°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 4.8" and February 2.0". The three wettest months together take 33% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
When it rains in Cahokia St Louis, it arrives in quantity
40.8" of precipitation falls across only about 117 wet days here, averaging 0.35 inches each. Fewer days carry more water: the year's total is delivered in comparatively heavy events rather than persistent damp.
- Days with measurable precipitation
- about 117 a year, 32% of all days
- Average depth per wet day
- 0.35 inches
- Most wet days
- May, about 14
- Fewest wet days
- January, about 8
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, and a per-day average is not a forecast of any individual storm.
Frost Dates & Growing Season
First Fall Freeze
October 26
50% probability date
Last Spring Freeze
April 8
50% probability date
Growing Season
201 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
4,547
Higher = more heating needed
Cooling Degree Days
1,476
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IL closest to Cahokia St Louis on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (57°F here).
- Beaver, OK 57°F · 0.0°F off
- Brookneal, VA 57°F · 0.0°F off
- Channing, TX 57°F · 0.0°F off
- Dumas, TX 57°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (40.8" here), excluding temperature-peer places.
- Donora, PA 40.9" · 0.0" off
- Gallatin, MO 40.8" · 0.0" off
- Ferris, TX 40.9" · 0.0" off
- Higginsville, MO 40.9" · 0.0" off
Data-derived climate profile
How Cahokia St Louis's climate pattern fits together
heating led · moderate · mid swing
Cahokia St Louis's energy balance leans toward cold weather: 4,547 annual heating degree days against 1,476 for cooling. Its 46.8°F seasonal range still makes the monthly rows more useful than the annual average alone.
Cahokia St Louis's frost-free season lasts about 201 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
July and January mark the typical warm and cold ends of the calendar in Cahokia St Louis's middle-range seasonal profile. The measured spread is 46.8°F. The annual average is 57°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Cahokia St Louis's 40.8 inches of annual precipitation falls in PlainClimate's middle band, so “wet” or “dry” is not the leading description. Snowfall is not added to the interpretation because its annual value is missing. Temperature balance and the calendar distribution carry more information than the annual moisture label alone.
These labels group NOAA 1991-2020 normals from Cahokia St Louis's primary station, so the winter figures are a thirty-year average and not a floor: a single hard season can run well below them. Treat each band as a descriptive range for Cahokia St Louis, not an official NOAA class or a year-ahead forecast.
Questions about Cahokia St Louis's climate
How much rain does Cahokia St Louis get? ▼
How many days above 90°F does Cahokia St Louis get? ▼
How much energy does heating and cooling require in Cahokia St Louis? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Cahokia St Louis's primary station: CAHOKIA ST LOUIS AP (USW00003960). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Cahokia St Louis; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Cahokia St Louis comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.