Jacksonville, 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 Jacksonville's primary NOAA station, JACKSONVILLE 2E - 2 stations mapped to the area.
The climate verdict for Jacksonville
Jacksonville, Illinois has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 53°F. Its climate comfort score of 68/100 (good) lands mid-pack nationally, exceeding 56% of station-mapped location scores.
- 53°F
- average temperature, NOAA 1991-2020 normal
- 68/100
- comfort score, above 56% of station-mapped location scores
- 39.3"
- annual precipitation · 16" snow
- 181 days
- frost-free days per growing season
Jacksonville: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00114442 · Jacksonville, IL 53°F mean · 39.3" precip
TEMP-COOL · RANK-MID · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-MID · LOAD-HEAT · STN-MULTI · BOOK-FULL
- TEMP-COOL 53°F
- RANK-MID #3,568
- PHOTO-FINISH ≈ Shoshone
- PRCP-MID 39.3"
- SWING-WIDE 48°F
- COMF-MID 68/100
- LOAD-HEAT 5,510 HDD
- STN-MULTI USC00114442
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Shoshone, ID (+ 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.
- Jacksonville (this station) 53°F
- Cold Chillicothe, MO 53°F
- Hot Ogden Pioneer P…, UT 53°F
- Near Shoshone, ID 53°F
- Near Windsor, IL 53°F
Climate Living Index · Jacksonville
Jacksonville: 60/100 · grade C
Jacksonville publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Jacksonville, not an official NOAA rating. Rankings still use Comfort Score 68/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 39.3 in · 4.3 from 35 in | 85/100 · A |
| Normal heat + freeze calendar | 129 calendar days | 59/100 · C |
| Snowfall burden | 16.2 inches/year | 54/100 · D |
| Annual temperature balance | 52.7°F · 14.8° from 67.5°F | 52/100 · D |
| Frost-free season | 181 days/year | 51/100 · D |
Jacksonville · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Jacksonville is a continental Köppen climate: Dfa
Coldest-month mean 27.1°F and warmest-month mean 75.3°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
- 75.3°F
- Coldest month
- 27.1°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 Jacksonville sits across the climate record
Three NOAA fields for Jacksonville's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 52nd percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 56th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 74%
- Warmest-to-coldest month gap for Jacksonville is large versus 6,861 complete station-years.
How Jacksonville compares across U.S. station-mapped locations
Jacksonville's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
68 Top 44% score exceeds 56% 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%). This entry sits in this band.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 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
Jacksonville's measured station temperature trend
MethodologyAcross 121 complete annual observations from 1896 to 2025, JACKSONVILLE 2E warmed at a fitted rate of 0.05°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Jacksonville primary station fitted change +0.05 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 36°F (2°C) | 18°F (-8°C) | 27°F (-3°C) | 1.9" | 5.1" | 28.2 | 0.0 |
| February | 41°F (5°C) | 21°F (-6°C) | 31°F (0°C) | 1.7" | 4.3" | 23.9 | 0.0 |
| March | 52°F (11°C) | 30°F (-1°C) | 41°F (5°C) | 2.8" | 2.0" | 19.8 | 0.0 |
| April | 65°F (18°C) | 40°F (5°C) | 53°F (11°C) | 4.3" | 0.3" | 6.4 | 0.1 |
| May | 75°F (24°C) | 52°F (11°C) | 63°F (17°C) | 4.8" | 0.0" | 0.4 | 1.0 |
| June | 83°F (29°C) | 61°F (16°C) | 72°F (22°C) | 4.9" | 0.0" | 0.0 | 5.8 |
| July | 87°F (30°C) | 64°F (18°C) | 75°F (24°C) | 4.0" | 0.0" | 0.0 | 9.9 |
| August | 85°F (30°C) | 62°F (17°C) | 73°F (23°C) | 3.4" | 0.0" | 0.0 | 7.3 |
| September | 80°F (27°C) | 54°F (12°C) | 67°F (19°C) | 3.5" | 0.0" | 0.2 | 4.0 |
| October | 68°F (20°C) | 42°F (6°C) | 55°F (13°C) | 3.0" | 0.0" | 5.6 | 0.3 |
| November | 53°F (12°C) | 32°F (0°C) | 43°F (6°C) | 3.0" | 1.0" | 17.6 | 0.0 |
| December | 41°F (5°C) | 23°F (-5°C) | 32°F (0°C) | 2.0" | 3.5" | 26.1 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 87°F around July 9, short of 90°F on every date, while 129 dates carry a normal low at or below freezing, the coldest 17°F near January 21.
The freezing stretch
The normal low stays at or below 32°F into March 22, then returns to freezing around November 15, covering 129 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 44% of years recorded at least a hundredth of an inch. The driest is January 28 at 24%. Summed across the calendar, that is about 116 wet dates a year.
The widest day
September 23 carries the biggest normal gap between afternoon and dawn, 27°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Jacksonville.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 5.1"
7.7 days with precipitation
Snow: 4.3"
7.2 days with precipitation
Snow: 2.0"
10.8 days with precipitation
Snow: 0.3"
12.3 days with precipitation
13.3 days with precipitation
10.5 days with precipitation
8.7 days with precipitation
8.9 days with precipitation
8.2 days with precipitation
9.9 days with precipitation
Snow: 1.0"
9.8 days with precipitation
Snow: 3.5"
8.1 days with precipitation
Jacksonville spreads its precipitation across the year
Neither half of the year dominates here: June through August take 31% of the annual total and December through February 14%, with neither reaching the 35% that would mark a distinct wet season. Jacksonville has no dry season to plan around, though it does carry a wide 48.2°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: June averages 4.9" and February 1.7". The three wettest months together take 36% 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.
How Jacksonville's precipitation splits across the calendar
About 115 days a year record measurable precipitation here, carrying 39.3" between them, or roughly 0.34 inches on a typical wet day. That sits in the middle band: neither the many-light-days pattern of the Pacific Northwest and the Great Lakes, nor the few-heavy-events pattern of the Gulf and the desert Southwest.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year and say nothing about the heaviest single storm on record.
Winter brings real snow to Jacksonville
Jacksonville averages 16.2 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 12 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: 16.2 inches of depth.
- Days recording measurable snow: about 12 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 4% 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 17
50% probability date
Last Spring Freeze
April 19
50% probability date
Growing Season
181 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
5,510
Higher = more heating needed
Cooling Degree Days
1,068
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IL closest to Jacksonville 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 (53°F here).
- Belleville, KS 53°F · 0.0°F off
- Cambridge, OH 53°F · 0.0°F off
- Cheyenne Wells, CO 53°F · 0.0°F off
- Cubero, NM 53°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (39.3" here), excluding temperature-peer places.
- Donnellson, IA 39.2" · 0.0" off
- Cumberland, MD 39.2" · 0.0" off
- Houlton, ME 39.3" · 0.0" off
- Lodi, WI 39.2" · 0.0" off
Snow and freeze rhythm
When cold and snow define Jacksonville
heating led · moderate · mid swing
Jacksonville's energy balance leans toward cold weather: 5,510 annual heating degree days against 1,068 for cooling. Its 48.2°F seasonal range still makes the monthly rows more useful than the annual average alone.
Jacksonville's frost-free season lasts about 181 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Jacksonville coldest normal
January
The monthly mean of 27°F (-3°C) sits near freezing, so cold nights and above-freezing afternoons share the same month.
-
2. Jacksonville typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Jacksonville snow peak
January
Jacksonville averages 16.2 inches of snow a year, with January the snowiest month on the normals.
Questions about Jacksonville's climate
How much snow does Jacksonville get? ▼
How cold does Jacksonville get in winter? ▼
How much energy does heating and cooling require in Jacksonville? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Jacksonville's primary station: JACKSONVILLE 2E (USC00114442). 2 NOAA stations are mapped to the Jacksonville area; the primary station's record is used for consistency. For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 1738115). Match rule for Jacksonville: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Jacksonville 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.