Knoxville, IA 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 Knoxville's primary NOAA station, KNOXVILLE.
The climate verdict for Knoxville
Knoxville, Iowa 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
- average temperature, NOAA 1991-2020 normal
- 68/100
- comfort score, above 56% of station-mapped location scores
- 37.5"
- precipitation, annual total
- 182 days
- growing season, frost-free days
Knoxville: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00134502 · Knoxville, IA 50°F mean · 37.5" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 50°F
- RANK-COOL #2,676
- PHOTO-FINISH ≈ Indianola
- PRCP-MID 37.5"
- SWING-WIDE 54°F
- COMF-MID 68/100
- LOAD-HEAT 6,415 HDD
- STN-1 USC00134502
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Indianola, IA (+ 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 IA station list.
- Knoxville (this station) 50°F
- Cold Osceola, IA 50°F
- Hot Seward, NE 50°F
- Near Indianola, IA 50°F
- Near Fulton L&d, IL 50°F
Climate Living Index · Knoxville
Knoxville: 56/100 · grade C
Knoxville publishes 4 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 2 missing weights rescale to 100.
PlainClimate-derived for Knoxville, not an official NOAA rating. Rankings still use Comfort Score 68/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 37.5 in · 2.5 from 35 in | 91/100 · A |
| Normal heat + freeze calendar | 140 calendar days | 53/100 · D |
| Frost-free season | 182 days/year | 51/100 · D |
| Annual temperature balance | 49.9°F · 17.6° from 67.5°F | 40/100 · D |
Knoxville · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Knoxville is a continental Köppen climate: Dfa
Coldest-month mean 21.2°F and warmest-month mean 75.1°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
- 75.1°F
- Coldest month
- 21.2°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 Knoxville sits across the climate record
Three NOAA fields for Knoxville's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 39th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 52nd percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 90%
- Warmest-to-coldest month gap for Knoxville is large versus 6,861 complete station-years.
How Knoxville compares across U.S. station-mapped locations
Knoxville'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
Knoxville's measured station temperature trend
MethodologyAcross 82 complete annual observations from 1896 to 2022, KNOXVILLE warmed at a fitted rate of 0.08°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Knoxville primary station fitted change +0.08 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|
| January | 30°F (-1°C) | 13°F (-11°C) | 21°F (-6°C) | 1.1" | 29.8 | 0.0 |
| February | 35°F (2°C) | 17°F (-8°C) | 26°F (-3°C) | 1.7" | 25.1 | 0.0 |
| March | 48°F (9°C) | 28°F (-2°C) | 38°F (3°C) | 1.9" | 21.0 | 0.0 |
| April | 61°F (16°C) | 39°F (4°C) | 50°F (10°C) | 3.9" | 6.5 | 0.0 |
| May | 71°F (22°C) | 51°F (11°C) | 61°F (16°C) | 5.0" | 0.3 | 0.5 |
| June | 81°F (27°C) | 61°F (16°C) | 71°F (22°C) | 5.6" | 0.0 | 3.4 |
| July | 85°F (29°C) | 66°F (19°C) | 75°F (24°C) | 4.3" | 0.0 | 8.3 |
| August | 83°F (28°C) | 63°F (17°C) | 73°F (23°C) | 3.9" | 0.0 | 5.6 |
| September | 76°F (25°C) | 54°F (12°C) | 65°F (19°C) | 3.7" | 0.1 | 2.2 |
| October | 63°F (17°C) | 42°F (6°C) | 53°F (11°C) | 3.1" | 4.6 | 0.0 |
| November | 48°F (9°C) | 30°F (-1°C) | 39°F (4°C) | 1.8" | 17.6 | 0.0 |
| December | 36°F (2°C) | 19°F (-7°C) | 27°F (-3°C) | 1.6" | 28.1 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 85°F around July 16, short of 90°F on every date, while 140 dates carry a normal low at or below freezing, the coldest 12°F near January 18.
The freezing stretch
The normal low stays at or below 32°F into March 28, then returns to freezing around November 10, covering 140 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 26, when 40% of years recorded at least a hundredth of an inch. The driest is January 8 at 17%. Summed across the calendar, that is about 96 wet dates a year.
The widest day
September 22 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 Knoxville.
Where Knoxville Stands Nationally
Days and nights track unusually close together; the widest normal swing, about 22°F, is narrower than most stations record.
Knoxville 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
4.9 days with precipitation
5.4 days with precipitation
7.9 days with precipitation
10.1 days with precipitation
12.3 days with precipitation
11.0 days with precipitation
7.8 days with precipitation
8.7 days with precipitation
7.8 days with precipitation
7.9 days with precipitation
6.3 days with precipitation
5.0 days with precipitation
Knoxville runs a summer-peaked wet season
37% of Knoxville's yearly precipitation falls in June, July and August alone, against the 25% an evenly spread year would give those three months. The wettest month is June at 5.6", on a wide 53.9°F gap between its warmest and coldest month. Warm-season convection and, across the Southwest, the North American monsoon produce this shape: rain arrives in short heavy bursts during the hottest part of the year rather than as long cool-season soaking.
- Wettest three months: June, May, July, taking 40% of the annual total between them.
- Driest month: January at 1.1".
- Winter share: 12% falls in December, January and February.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. A summer-peaked label means the June-August share reaches 35%; it describes timing across an average year, not any single season, and says nothing about how heavy an individual storm can be.
When it rains in Knoxville, it arrives in quantity
37.4" of precipitation falls across only about 95 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 95 a year, 26% of all days
- Average depth per wet day
- 0.39 inches
- Most wet days
- May, about 12
- Fewest wet days
- January, about 5
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 19
50% probability date
Last Spring Freeze
April 20
50% probability date
Growing Season
182 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,415
Higher = more heating needed
Cooling Degree Days
950
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IA closest to Knoxville 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).
- Chalmers, IN 50°F · 0.0°F off
- Coulee Dam, WA 50°F · 0.0°F off
- Genoa, CO 50°F · 0.0°F off
- Holdrege, NE 50°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (37.5" here), excluding temperature-peer places.
- Fremont, MI 37.5" · 0.0" off
- Ralston, OK 37.4" · 0.0" off
- Congerville, IL 37.5" · 0.0" off
- La Crosse, WI 37.5" · 0.0" off
Data-derived climate profile
How Knoxville's climate pattern fits together
heating led · moderate · mid swing
Knoxville's energy balance leans toward cold weather: 6,415 annual heating degree days against 950 for cooling. Its 53.9°F seasonal range still makes the monthly rows more useful than the annual average alone.
Knoxville's frost-free season lasts about 182 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 Knoxville's middle-range seasonal profile. The measured spread is 53.9°F. The annual average is 50°F. Neither the annual mean nor one extreme month represents the full calendar on its own.
Knoxville's 37.5 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 Knoxville'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 Knoxville, not an official NOAA class or a year-ahead forecast.
Questions about Knoxville's climate
How much rain does Knoxville get? ▼
How cold does Knoxville get in winter? ▼
How much energy does heating and cooling require in Knoxville? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Knoxville's primary station: KNOXVILLE (USC00134502). 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 1942015). Match rule for Knoxville: 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 Knoxville 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.