Rock Island L&d, IL Climate: Temperature & Rain by Month
Annual temperature and rainfall from NOAA NCEI's 1991–2020 normals →; comfort score computed by PlainClimate
30-year climate normals (1991-2020) from Rock Island L&d's primary NOAA station, ROCK ISLAND L&D 15.
The climate verdict for Rock Island L&d
Rock Island L&d, Illinois has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 50°F. Its climate comfort score of 68/100 (good) lands mid-pack nationally, exceeding 56% of station-mapped location scores.
- 50°F
- yearly average temperature, NOAA normal
- 68/100
- comfort score, above 56% of station-mapped location scores
- 38.8"
- precipitation, annual total
- 186 days
- frost-free growing season
Rock Island L&d: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00117391 · Rock Island L&d, IL 50°F mean · 38.8" precip
TEMP-COOL · RANK-MID · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 50°F
- RANK-MID #2,813
- PHOTO-FINISH ≈ Aurora
- PRCP-MID 38.8"
- SWING-WIDE 52°F
- COMF-MID 68/100
- LOAD-HEAT 6,241 HDD
- STN-1 USC00117391
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Aurora, IL ( -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.
- Hot Oxford, NE 51°F
- Rock Island L&d (this station) 50°F
- Cold Aurora, IL 50°F
- Near Clinton, IA 50°F
- Near Illinois City D…, IL 50°F
Climate Living Index · Rock Island L&d
Rock Island L&d: 56/100 · grade C
Rock Island L&d publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Rock Island L&d, not an official NOAA rating. Rankings still use Comfort Score 68/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 38.8 in · 3.8 from 35 in | 86/100 · A |
| Frost-free season | 186 days/year | 54/100 · D |
| Normal heat + freeze calendar | 138 calendar days | 54/100 · D |
| Annual temperature balance | 50.3°F · 17.2° from 67.5°F | 42/100 · D |
Rock Island L&d · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Rock Island L&d is a continental Köppen climate: Dfa
Coldest-month mean 22.2°F and warmest-month mean 74.4°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
- 74.4°F
- Coldest month
- 22.2°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 Rock Island L&d sits across the climate record
Three NOAA fields for Rock Island L&d's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 41st percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 55th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 86%
- Warmest-to-coldest month gap for Rock Island L&d is large versus 6,861 complete station-years.
How Rock Island L&d compares across U.S. station-mapped locations
Rock Island L&d'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
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 31°F (-1°C) | 13°F (-10°C) | 22°F (-5°C) | 1.5" | 28.8 | 0.0 |
| February | 36°F (2°C) | 18°F (-8°C) | 27°F (-3°C) | 1.8" | 24.6 | 0.0 |
| March | 48°F (9°C) | 28°F (-2°C) | 38°F (3°C) | 2.6" | 18.2 | 0.0 |
| April | 61°F (16°C) | 39°F (4°C) | 50°F (10°C) | 3.8" | 4.1 | 0.0 |
| May | 72°F (22°C) | 51°F (10°C) | 62°F (16°C) | 5.1" | 0.1 | 0.9 |
| June | 81°F (27°C) | 61°F (16°C) | 71°F (22°C) | 5.2" | 0.0 | 4.1 |
| July | 84°F (29°C) | 65°F (18°C) | 74°F (24°C) | 4.2" | 0.0 | 6.6 |
| August | 82°F (28°C) | 63°F (17°C) | 73°F (23°C) | 4.0" | 0.0 | 4.3 |
| September | 77°F (25°C) | 55°F (13°C) | 66°F (19°C) | 3.3" | 0.0 | 2.0 |
| October | 64°F (18°C) | 43°F (6°C) | 53°F (12°C) | 2.9" | 1.9 | 0.1 |
| November | 49°F (9°C) | 30°F (-1°C) | 39°F (4°C) | 2.3" | 14.1 | 0.0 |
| December | 36°F (2°C) | 20°F (-7°C) | 28°F (-2°C) | 2.0" | 26.1 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 84°F around July 9, short of 90°F on every date, while 138 dates carry a normal low at or below freezing, the coldest 13°F near January 17.
The freezing stretch
The normal low stays at or below 32°F into March 27, then returns to freezing around November 11, covering 138 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 43% of years recorded at least a hundredth of an inch. The driest is July 25 at 29%. Summed across the calendar, that is about 123 wet dates a year.
The widest day
April 7 carries the biggest normal gap between afternoon and dawn, 22°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Rock Island L&d.
Where Rock Island L&d Stands Nationally
Days and nights track unusually close together; the widest normal swing, about 22°F, is narrower than most stations record.
Rock Island L&d earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall
10.6 days with precipitation
8.9 days with precipitation
10.1 days with precipitation
11.9 days with precipitation
13.1 days with precipitation
12.1 days with precipitation
8.5 days with precipitation
9.6 days with precipitation
8.4 days with precipitation
9.5 days with precipitation
9.7 days with precipitation
10.3 days with precipitation
Rock Island L&d spreads its precipitation across the year
Neither half of the year dominates here: June through August take 35% of the annual total and December through February 14%, with neither reaching the 35% that would mark a distinct wet season. Rock Island L&d has no dry season to plan around, though it does carry a wide 52.2°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: June averages 5.2" and January 1.5". The three wettest months together take 38% 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 Rock Island L&d's precipitation splits across the calendar
About 123 days a year record measurable precipitation here, carrying 38.8" between them, or roughly 0.32 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.
Frost Dates & Growing Season
First Fall Freeze
October 22
50% probability date
Last Spring Freeze
April 19
50% probability date
Growing Season
186 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,241
Higher = more heating needed
Cooling Degree Days
935
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IL closest to Rock Island L&d 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 (50°F here).
- Bedford, IA 50°F · 0.0°F off
- Boulder, UT 50°F · 0.0°F off
- Central City, NE 50°F · 0.0°F off
- Chatham, MA 50°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (38.8" here), excluding temperature-peer places.
- Blackwell, OK 38.8" · 0.0" off
- Elkader, IA 38.8" · 0.0" off
- Columbus Junction, IA 38.8" · 0.0" off
- Angola, IN 38.8" · 0.0" off
Data-derived climate profile
How Rock Island L&d's climate pattern fits together
heating led · moderate · mid swing
Rock Island L&d's energy balance leans toward cold weather: 6,241 annual heating degree days against 935 for cooling. Its 52.2°F seasonal range still makes the monthly rows more useful than the annual average alone.
Rock Island L&d's frost-free season lasts about 186 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 Rock Island L&d's middle-range seasonal profile. The measured spread is 52.2°F. The annual average is 50°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Rock Island L&d's 38.8 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 Rock Island L&d'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 Rock Island L&d, not an official NOAA class or a year-ahead forecast.
Questions about Rock Island L&d's climate
How much rain does Rock Island L&d get? ▼
How cold does Rock Island L&d get in winter? ▼
How much energy does heating and cooling require in Rock Island L&d? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Rock Island L&d's primary station: ROCK ISLAND L&D 15 (USC00117391). 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 Rock Island L&d; 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 Rock Island L&d 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.