Onawa, IA Climate: Temperature & Rain by Month
Pulled from NOAA NCEI 1991–2020 normals →: climate measurements used in PlainClimate's documented score
30-year climate normals (1991-2020) from Onawa's primary NOAA station, ONAWA 3NW.
The climate verdict for Onawa
Onawa, Iowa has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 49°F. Its climate comfort score of 59/100 (moderate) lands mid-pack nationally, exceeding 37% of station-mapped location scores.
- 49°F
- yearly average temperature, NOAA normal
- 59/100
- comfort score, above 37% of station-mapped location scores
- 29.9"
- annual precipitation · 31" snow
- 155 days
- growing season, frost-free days
Onawa: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00136243 · Onawa, IA 49°F mean · 29.9" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 49°F
- RANK-COOL #2,333
- PHOTO-FINISH ≈ Sioux City Gate…
- PRCP-MID 29.9"
- SWING-WIDE 55°F
- COMF-MID 59/100
- LOAD-HEAT 6,845 HDD
- STN-1 USC00136243
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Sioux City Gateway, 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.
- Onawa (this station) 49°F
- Hot Newton, IA 49°F
- Near Sioux City Gate…, IA 49°F
- Cold Guthrie Ctr, IA 48°F
- Near Dubuque L&d, IA 48°F
Climate Living Index · Onawa
Onawa: 43/100 · grade D
Onawa publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Onawa, not an official NOAA rating. Rankings still use Comfort Score 59/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 29.9 in · 5.1 from 35 in | 82/100 · B |
| Snowfall burden | 31.0 inches/year | 37/100 · F |
| Normal heat + freeze calendar | 164 calendar days | 36/100 · F |
| Annual temperature balance | 48.5°F · 19.0° from 67.5°F | 34/100 · F |
| Frost-free season | 155 days/year | 29/100 · F |
Onawa · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Onawa is a continental Köppen climate: Dfa
Coldest-month mean 19.4°F and warmest-month mean 74.3°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
- 74.3°F
- Coldest month
- 19.4°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 Onawa sits across the climate record
Three NOAA fields for Onawa's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 34th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 40th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 92%
- Warmest-to-coldest month gap for Onawa is large versus 6,861 complete station-years.
How Onawa compares across U.S. station-mapped locations
Onawa's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
59 37th percentile score exceeds 37% 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%). This entry sits in this band.
- 60–70: 1,236 station-mapped locations (20%). Above this entry.
- 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 | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 30°F (-1°C) | 9°F (-13°C) | 19°F (-7°C) | 0.5" | 7.9" | 30.5 | 0.0 |
| February | 36°F (2°C) | 13°F (-11°C) | 24°F (-4°C) | 0.8" | 6.6" | 26.0 | 0.0 |
| March | 50°F (10°C) | 24°F (-5°C) | 37°F (3°C) | 1.6" | 4.5" | 22.6 | 0.0 |
| April | 63°F (17°C) | 35°F (2°C) | 49°F (9°C) | 3.3" | 1.8" | 9.2 | 0.4 |
| May | 74°F (23°C) | 48°F (9°C) | 61°F (16°C) | 4.6" | 0.0" | 0.8 | 1.7 |
| June | 83°F (28°C) | 59°F (15°C) | 71°F (22°C) | 4.2" | 0.0" | 0.0 | 5.5 |
| July | 86°F (30°C) | 63°F (17°C) | 74°F (24°C) | 3.4" | 0.0" | 0.0 | 9.3 |
| August | 84°F (29°C) | 59°F (15°C) | 72°F (22°C) | 4.1" | 0.0" | 0.0 | 6.1 |
| September | 78°F (26°C) | 50°F (10°C) | 64°F (18°C) | 3.0" | 0.0" | 0.9 | 2.9 |
| October | 65°F (19°C) | 37°F (3°C) | 51°F (11°C) | 2.3" | 0.3" | 8.6 | 0.5 |
| November | 49°F (9°C) | 24°F (-5°C) | 36°F (2°C) | 1.5" | 2.8" | 22.7 | 0.0 |
| December | 34°F (1°C) | 14°F (-10°C) | 24°F (-4°C) | 0.7" | 7.1" | 29.5 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 86°F around July 10, short of 90°F on every date, while 164 dates carry a normal low at or below freezing, the coldest 8°F near January 19.
The freezing stretch
The normal low stays at or below 32°F into April 8, then returns to freezing around October 28, covering 164 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 28, when 31% of years recorded at least a hundredth of an inch. The driest is December 22 at 12%. Summed across the calendar, that is about 76 wet dates a year.
The widest day
September 30 carries the biggest normal gap between afternoon and dawn, 29°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Onawa.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 7.9"
4.6 days with precipitation
Snow: 6.6"
4.4 days with precipitation
Snow: 4.5"
5.8 days with precipitation
Snow: 1.8"
8.0 days with precipitation
9.2 days with precipitation
8.8 days with precipitation
7.5 days with precipitation
6.9 days with precipitation
6.4 days with precipitation
Snow: 0.3"
5.3 days with precipitation
Snow: 2.8"
4.7 days with precipitation
Snow: 7.1"
3.6 days with precipitation
Onawa runs a summer-peaked wet season
39% of Onawa'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 May at 4.6", on a wide 54.9°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: May, June, August, taking 43% of the annual total between them.
- Driest month: January at 0.5".
- Winter share: 7% 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 Onawa, it arrives in quantity
29.9" of precipitation falls across only about 75 wet days here, averaging 0.40 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 75 a year, 21% of all days
- Average depth per wet day
- 0.40 inches
- Most wet days
- May, about 9
- Fewest wet days
- December, about 4
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 Onawa
Onawa averages 31.0 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 16 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: 31.0 inches of depth.
- Days recording measurable snow: about 16 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 10% 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 3
50% probability date
Last Spring Freeze
May 1
50% probability date
Growing Season
155 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,845
Higher = more heating needed
Cooling Degree Days
876
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IA closest to Onawa 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 (49°F here).
- Butler, PA 49°F · 0.0°F off
- Fredericktown, OH 49°F · 0.0°F off
- Grosse Pointe Farms, MI 49°F · 0.0°F off
- Lakeville, IN 49°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (29.9" here), excluding temperature-peer places.
- Clearlake, CA 29.9" · 0.0" off
- Courtland, KS 29.9" · 0.0" off
- Babbitt, MN 29.8" · 0.0" off
- Walthill, NE 29.8" · 0.1" off
Snow and freeze rhythm
When cold and snow define Onawa
heating led · moderate · mid swing
Onawa's energy balance leans toward cold weather: 6,845 annual heating degree days against 876 for cooling. Its 54.9°F seasonal range still makes the monthly rows more useful than the annual average alone.
Onawa's frost-free season lasts about 155 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Onawa coldest normal
January
Averaging 19°F (-7°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Onawa typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Onawa snow peak
January
Onawa averages 31.0 inches of snow a year, with January the snowiest month on the normals.
Questions about Onawa's climate
How much snow does Onawa get? ▼
How cold does Onawa get in winter? ▼
How much energy does heating and cooling require in Onawa? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Onawa's primary station: ONAWA 3NW (USC00136243). 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 1959115). Match rule for Onawa: 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 Onawa 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.