Decorah, IA 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 Decorah's primary NOAA station, DECORAH.
The climate verdict for Decorah
Decorah, 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
- average temperature, NOAA 1991-2020 normal
- 59/100
- comfort score, above 37% of station-mapped location scores
- 37.6"
- annual precipitation · 38" snow
- 157 days
- frost-free growing season
Decorah: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00132110 · Decorah, IA 49°F mean · 37.6" 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 ≈ Guttenberg L&d
- PRCP-MID 37.6"
- SWING-WIDE 55°F
- COMF-MID 59/100
- LOAD-HEAT 6,795 HDD
- STN-1 USC00132110
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Guttenberg L&d, 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.
- Decorah (this station) 49°F
- Hot Wendover, NV 49°F
- Near Guttenberg L&d, IA 49°F
- Near Madison, NE 49°F
- Near Genoa Dam, WI 49°F
Climate Living Index · Decorah
Decorah: 47/100 · grade D
Decorah publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Decorah, not an official NOAA rating. Rankings still use Comfort Score 59/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 37.6 in · 2.6 from 35 in | 90/100 · A |
| Normal heat + freeze calendar | 146 calendar days | 49/100 · D |
| Annual temperature balance | 48.5°F · 19.0° from 67.5°F | 34/100 · F |
| Frost-free season | 157 days/year | 31/100 · F |
| Snowfall burden | 37.5 inches/year | 30/100 · F |
Decorah · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Decorah is a continental Köppen climate: Dfa
Coldest-month mean 19.0°F and warmest-month mean 73.5°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
- 73.5°F
- Coldest month
- 19.0°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 Decorah sits across the climate record
Three NOAA fields for Decorah'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
- 53rd percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 91%
- Warmest-to-coldest month gap for Decorah is large versus 6,861 complete station-years.
How Decorah compares across U.S. station-mapped locations
Decorah'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
Decorah's measured station temperature trend
MethodologyAcross 105 complete annual observations from 1895 to 2025, DECORAH warmed at a fitted rate of 0.09°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Decorah primary station fitted change +0.09 °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 | 28°F (-2°C) | 10°F (-12°C) | 19°F (-7°C) | 1.0" | 10.3" | 30.4 | 0.0 |
| February | 33°F (0°C) | 14°F (-10°C) | 23°F (-5°C) | 1.1" | 8.3" | 26.5 | 0.0 |
| March | 46°F (8°C) | 26°F (-3°C) | 36°F (2°C) | 2.0" | 5.7" | 23.6 | 0.0 |
| April | 61°F (16°C) | 37°F (3°C) | 49°F (10°C) | 4.0" | 1.7" | 11.2 | 0.0 |
| May | 73°F (23°C) | 48°F (9°C) | 61°F (16°C) | 4.9" | 0.0" | 1.8 | 0.9 |
| June | 81°F (27°C) | 59°F (15°C) | 70°F (21°C) | 6.1" | 0.0" | 0.0 | 2.9 |
| July | 84°F (29°C) | 63°F (17°C) | 74°F (23°C) | 4.4" | 0.0" | 0.0 | 4.5 |
| August | 83°F (28°C) | 61°F (16°C) | 72°F (22°C) | 4.4" | 0.0" | 0.0 | 2.6 |
| September | 76°F (25°C) | 52°F (11°C) | 64°F (18°C) | 3.6" | 0.0" | 0.7 | 1.2 |
| October | 63°F (17°C) | 40°F (5°C) | 52°F (11°C) | 2.7" | 0.0" | 8.8 | 0.1 |
| November | 47°F (8°C) | 28°F (-2°C) | 38°F (3°C) | 2.0" | 2.4" | 21.1 | 0.0 |
| December | 33°F (0°C) | 17°F (-8°C) | 25°F (-4°C) | 1.3" | 9.1" | 29.0 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 85°F around July 8, short of 90°F on every date, while 146 dates carry a normal low at or below freezing, the coldest 9°F near January 22.
The freezing stretch
The normal low stays at or below 32°F into March 31, then returns to freezing around November 7, covering 146 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 44% of years recorded at least a hundredth of an inch. The driest is February 17 at 22%. Summed across the calendar, that is about 114 wet dates a year.
The widest day
April 28 carries the biggest normal gap between afternoon and dawn, 25°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Decorah.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 10.3"
7.5 days with precipitation
Snow: 8.3"
6.2 days with precipitation
Snow: 5.7"
8.0 days with precipitation
Snow: 1.7"
12.0 days with precipitation
13.4 days with precipitation
12.2 days with precipitation
9.9 days with precipitation
10.0 days with precipitation
9.3 days with precipitation
9.4 days with precipitation
Snow: 2.4"
7.6 days with precipitation
Snow: 9.1"
8.4 days with precipitation
Decorah runs a summer-peaked wet season
40% of Decorah'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 6.1", on a wide 54.5°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 41% of the annual total between them.
- Driest month: January at 1.0".
- Winter share: 9% 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.
How Decorah's precipitation splits across the calendar
About 114 days a year record measurable precipitation here, carrying 37.6" between them, or roughly 0.33 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 Decorah
Decorah averages 37.5 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 23 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: 37.5 inches of depth.
- Days recording measurable snow: about 23 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 7
50% probability date
Last Spring Freeze
May 3
50% probability date
Growing Season
157 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,795
Higher = more heating needed
Cooling Degree Days
828
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IA closest to Decorah 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 (37.6" here), excluding temperature-peer places.
- Marengo, IL 37.6" · 0.0" off
- Valley Falls, KS 37.6" · 0.0" off
- Kenosha, WI 37.6" · 0.0" off
- Avon, IL 37.6" · 0.0" off
Snow and freeze rhythm
When cold and snow define Decorah
heating led · moderate · mid swing
Decorah's energy balance leans toward cold weather: 6,795 annual heating degree days against 828 for cooling. Its 54.5°F seasonal range still makes the monthly rows more useful than the annual average alone.
Decorah's frost-free season lasts about 157 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Decorah coldest normal
January
Averaging 19°F (-7°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Decorah typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Decorah snow peak
January
Decorah averages 37.5 inches of snow a year, with January the snowiest month on the normals.
Questions about Decorah's climate
How much snow does Decorah get? ▼
How cold does Decorah get in winter? ▼
How much energy does heating and cooling require in Decorah? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Decorah's primary station: DECORAH (USC00132110). 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 1919405). Match rule for Decorah: 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 Decorah 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.