Cahokia, IL Climate: Temperature & Rain by Month
Temperature and precipitation from NOAA NCEI 1991–2020 normals →, plus PlainClimate's derived comfort score
30-year climate normals (1991-2020) from Cahokia's primary NOAA station, CAHOKIA.
The climate verdict for Cahokia
Cahokia, Illinois has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 56°F. It scores 78/100 for climate comfort (good), putting it in the top third of station-mapped location scores and exceeding 72% of them.
- 56°F
- yearly average temperature, NOAA normal
- 78/100
- comfort score, above 72% of station-mapped location scores
- 42.8"
- annual precipitation · 14" snow
- 204 days
- frost-free growing season
Cahokia: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00111160 · Cahokia, IL 56°F mean · 42.8" precip
TEMP-MILD · RANK-UPPER · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-TOP · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-MILD 56°F
- RANK-UPPER #4,391
- PHOTO-FINISH ≈ Osceola
- PRCP-MID 42.8"
- SWING-WIDE 47°F
- COMF-TOP 78/100
- LOAD-HEAT 4,631 HDD
- STN-1 USC00111160
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Osceola, MO (+ 0.1 °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 (this station) 56°F
- Cold Paria Ranger St…, UT 56°F
- Hot Osceola, MO 56°F
- Near St Louis Sprt o…, MO 56°F
- Near Eldon, MO 56°F
Climate Living Index · Cahokia
Cahokia: 68/100 · grade C
Cahokia publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Cahokia, not an official NOAA rating. Rankings still use Comfort Score 78/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Normal heat + freeze calendar | 103 calendar days | 74/100 · B |
| Precipitation balance | 42.8 in · 7.8 from 35 in | 73/100 · B |
| Frost-free season | 204 days/year | 67/100 · C |
| Annual temperature balance | 56.2°F · 11.3° from 67.5°F | 64/100 · C |
| Snowfall burden | 13.8 inches/year | 58/100 · C |
Cahokia · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Cahokia is a continental Köppen climate: Dfa
Coldest-month mean 31.4°F and warmest-month mean 78.7°F place this station in continental, no dry season, hot summer climates (Dfa). Class Dfa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, hot summer.
- Köppen code
- Dfa
- Group
- Continental
- Warmest month
- 78.7°F
- Coldest month
- 31.4°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 sits across the climate record
Three NOAA fields for Cahokia's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 64th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 64th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- 69th percentile swing
- Typical seasonal amplitude versus 6,861 complete station-years.
How Cahokia compares across U.S. station-mapped locations
Cahokia's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
78 Top 28% score exceeds 72% 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%). This entry sits in this band.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 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 | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 41°F (5°C) | 22°F (-6°C) | 31°F (0°C) | 2.7" | 4.9" | 25.2 | 0.0 |
| February | 46°F (8°C) | 26°F (-4°C) | 36°F (2°C) | 2.3" | 3.7" | 20.4 | 0.0 |
| March | 56°F (13°C) | 35°F (2°C) | 45°F (7°C) | 3.5" | 1.2" | 12.9 | 0.0 |
| April | 68°F (20°C) | 45°F (7°C) | 57°F (14°C) | 4.6" | 0.3" | 2.6 | 0.2 |
| May | 76°F (24°C) | 56°F (13°C) | 66°F (19°C) | 4.8" | 0.0" | 0.0 | 1.4 |
| June | 85°F (29°C) | 65°F (18°C) | 75°F (24°C) | 4.3" | 0.0" | 0.0 | 7.8 |
| July | 89°F (31°C) | 69°F (21°C) | 79°F (26°C) | 5.0" | 0.0" | 0.0 | 14.4 |
| August | 87°F (31°C) | 67°F (19°C) | 77°F (25°C) | 3.1" | 0.0" | 0.0 | 11.6 |
| September | 80°F (27°C) | 59°F (15°C) | 70°F (21°C) | 3.4" | 0.0" | 0.0 | 3.8 |
| October | 70°F (21°C) | 46°F (8°C) | 58°F (14°C) | 3.0" | 0.0" | 2.1 | 0.3 |
| November | 56°F (13°C) | 35°F (2°C) | 46°F (8°C) | 3.3" | 0.8" | 11.0 | 0.0 |
| December | 45°F (7°C) | 27°F (-3°C) | 36°F (2°C) | 2.8" | 2.9" | 22.9 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 89°F around July 11, short of 90°F on every date, while 103 dates carry a normal low at or below freezing, the coldest 22°F near January 17.
The freezing stretch
The normal low stays at or below 32°F into March 7, then returns to freezing around November 26, covering 103 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 1, when 42% of years recorded at least a hundredth of an inch. The driest is September 3 at 23%. Summed across the calendar, that is about 111 wet dates a year.
The widest day
October 16 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.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 4.9"
9.0 days with precipitation
Snow: 3.7"
7.9 days with precipitation
Snow: 1.2"
10.4 days with precipitation
Snow: 0.3"
11.6 days with precipitation
12.2 days with precipitation
10.2 days with precipitation
8.4 days with precipitation
7.6 days with precipitation
7.2 days with precipitation
8.2 days with precipitation
Snow: 0.8"
8.3 days with precipitation
Snow: 2.9"
9.5 days with precipitation
Cahokia 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 18%, with neither reaching the 35% that would mark a distinct wet season. Cahokia has no dry season to plan around, though it does carry a wide 47.3°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: July averages 5.0" and February 2.3". The three wettest months together take 34% 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, it arrives in quantity
42.8" of precipitation falls across only about 111 wet days here, averaging 0.39 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 111 a year, 30% of all days
- Average depth per wet day
- 0.39 inches
- Most wet days
- May, about 12
- Fewest wet days
- September, about 7
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.
Winter brings real snow to Cahokia
Cahokia averages 13.8 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 9 days that record measurable snow. That is depth accumulating on the ground, which is why it can exceed the annual precipitation figure: precipitation counts the liquid the snow melts down to, and fresh snow is mostly air.
- Annual snowfall: 13.8 inches of depth.
- Days recording measurable snow: about 9 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 3% of the year's precipitation.
NOAA 1991-2020 normals. The ten-to-one ratio is a convention, not a measurement: real ratios vary with temperature, so treat the share as an order of magnitude rather than an exact split.
Frost Dates & Growing Season
First Fall Freeze
October 27
50% probability date
Last Spring Freeze
April 6
50% probability date
Growing Season
204 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
4,631
Higher = more heating needed
Cooling Degree Days
1,459
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IL closest to Cahokia 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 (56°F here).
- Baltimore, MD 56°F · 0.0°F off
- Cape May, NJ 56°F · 0.0°F off
- Carrizozo, NM 56°F · 0.0°F off
- Galena, MO 56°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (42.8" here), excluding temperature-peer places.
- Healdsburg, CA 42.8" · 0.0" off
- Gainesville, TX 42.8" · 0.0" off
- Moberly, MO 42.7" · 0.1" off
- Lexington, VA 42.9" · 0.1" off
Snow and freeze rhythm
When cold and snow define Cahokia
heating led · moderate · mid swing
Cahokia's energy balance leans toward cold weather: 4,631 annual heating degree days against 1,459 for cooling. Its 47.3°F seasonal range still makes the monthly rows more useful than the annual average alone.
Cahokia's frost-free season lasts about 204 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Cahokia coldest normal
January
The monthly mean of 31°F (0°C) sits near freezing, so cold nights and above-freezing afternoons share the same month.
-
2. Cahokia typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Cahokia snow peak
January
Cahokia averages 13.8 inches of snow a year, with January the snowiest month on the normals.
Questions about Cahokia's climate
How much snow does Cahokia get? ▼
How many days above 90°F does Cahokia get? ▼
How much energy does heating and cooling require in Cahokia? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Cahokia's primary station: CAHOKIA (USC00111160). 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; 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 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.