Decatur, IN 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 Decatur's primary NOAA station, DECATUR 1 N.
The climate verdict for Decatur
Decatur, Indiana has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 51°F. Its climate comfort score of 59/100 (moderate) lands mid-pack nationally, exceeding 37% of station-mapped location scores.
- 51°F
- average temperature, NOAA 1991-2020 normal
- 59/100
- comfort score, above 37% of station-mapped location scores
- 40.6"
- annual precipitation · 28" snow
- 179 days
- frost-free days per growing season
Decatur: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00122096 · Decatur, IN 51°F mean · 40.6" precip
TEMP-COOL · RANK-MID · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 51°F
- RANK-MID #2,950
- PHOTO-FINISH ≈ Winchester Airp…
- PRCP-MID 40.6"
- SWING-WIDE 48°F
- COMF-MID 59/100
- LOAD-HEAT 6,010 HDD
- STN-1 USC00122096
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Winchester Airport, IN (+ 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 IN station list.
- Decatur (this station) 51°F
- Cold Marion, OH 51°F
- Hot Winchester Airp…, IN 51°F
- Near Paradox, CO 51°F
- Near Bellefontaine, OH 51°F
Climate Living Index · Decatur
Decatur: 55/100 · grade C
Decatur publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Decatur, not an official NOAA rating. Rankings still use Comfort Score 59/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 40.6 in · 5.6 from 35 in | 80/100 · B |
| Normal heat + freeze calendar | 130 calendar days | 59/100 · C |
| Frost-free season | 179 days/year | 49/100 · D |
| Annual temperature balance | 50.7°F · 16.8° from 67.5°F | 43/100 · D |
| Snowfall burden | 28.1 inches/year | 40/100 · D |
Decatur · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Decatur is a continental Köppen climate: Dfa
Coldest-month mean 25.7°F and warmest-month mean 73.2°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
- 73.2°F
- Coldest month
- 25.7°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 Decatur sits across the climate record
Three NOAA fields for Decatur's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 43rd percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 59th percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 70%
- Warmest-to-coldest month gap for Decatur is large versus 6,861 complete station-years.
How Decatur compares across U.S. station-mapped locations
Decatur'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 | 33°F (1°C) | 18°F (-8°C) | 26°F (-4°C) | 2.5" | 9.2" | 27.2 | 0.0 |
| February | 36°F (2°C) | 20°F (-6°C) | 28°F (-2°C) | 2.1" | 7.5" | 25.1 | 0.0 |
| March | 48°F (9°C) | 29°F (-2°C) | 38°F (3°C) | 2.8" | 4.2" | 21.5 | 0.0 |
| April | 61°F (16°C) | 39°F (4°C) | 50°F (10°C) | 4.1" | 0.5" | 8.1 | 0.0 |
| May | 72°F (22°C) | 50°F (10°C) | 61°F (16°C) | 4.8" | 0.0" | 0.3 | 0.9 |
| June | 81°F (27°C) | 60°F (16°C) | 71°F (21°C) | 4.6" | 0.0" | 0.0 | 3.9 |
| July | 84°F (29°C) | 63°F (17°C) | 73°F (23°C) | 4.3" | 0.0" | 0.0 | 6.4 |
| August | 82°F (28°C) | 61°F (16°C) | 71°F (22°C) | 4.0" | 0.0" | 0.0 | 3.9 |
| September | 77°F (25°C) | 53°F (12°C) | 65°F (18°C) | 3.0" | 0.0" | 0.0 | 2.3 |
| October | 64°F (18°C) | 42°F (6°C) | 53°F (12°C) | 2.9" | 0.0" | 3.9 | 0.1 |
| November | 50°F (10°C) | 33°F (0°C) | 41°F (5°C) | 3.0" | 1.2" | 15.8 | 0.0 |
| December | 38°F (3°C) | 24°F (-4°C) | 31°F (0°C) | 2.6" | 5.5" | 25.1 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 84°F around July 10, short of 90°F on every date, while 130 dates carry a normal low at or below freezing, the coldest 18°F near January 22.
The freezing stretch
The normal low stays at or below 32°F into March 26, then returns to freezing around November 18, covering 130 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 April 28, when 43% of years recorded at least a hundredth of an inch. The driest is September 2 at 28%. Summed across the calendar, that is about 128 wet dates a year.
The widest day
September 22 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 Decatur.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 9.2"
10.9 days with precipitation
Snow: 7.5"
9.0 days with precipitation
Snow: 4.2"
11.2 days with precipitation
Snow: 0.5"
13.0 days with precipitation
12.9 days with precipitation
11.7 days with precipitation
10.0 days with precipitation
9.3 days with precipitation
8.4 days with precipitation
9.9 days with precipitation
Snow: 1.2"
10.4 days with precipitation
Snow: 5.5"
10.7 days with precipitation
Decatur spreads its precipitation across the year
Neither half of the year dominates here: June through August take 32% of the annual total and December through February 18%, with neither reaching the 35% that would mark a distinct wet season. Decatur has no dry season to plan around, though it does carry a wide 47.5°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 4.8" and February 2.1". The three wettest months together take 33% 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 Decatur's precipitation splits across the calendar
About 127 days a year record measurable precipitation here, carrying 40.6" 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.
Winter brings real snow to Decatur
Decatur averages 28.1 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 19 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: 28.1 inches of depth.
- Days recording measurable snow: about 19 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 7% 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 19
50% probability date
Last Spring Freeze
April 23
50% probability date
Growing Season
179 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
6,010
Higher = more heating needed
Cooling Degree Days
818
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside IN closest to Decatur 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 (51°F here).
- Ellicott, CO 51°F · 0.0°F off
- Fort Collins, CO 51°F · 0.0°F off
- Fredonia, NY 51°F · 0.0°F off
- Fremont, OH 51°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (40.6" here), excluding temperature-peer places.
- Asheville, NC 40.6" · 0.0" off
- Bowling Green, MO 40.6" · 0.0" off
- Franklin, TX 40.6" · 0.0" off
- Garnett, KS 40.6" · 0.0" off
Snow and freeze rhythm
When cold and snow define Decatur
heating led · moderate · mid swing
Decatur's energy balance leans toward cold weather: 6,010 annual heating degree days against 818 for cooling. Its 47.5°F seasonal range still makes the monthly rows more useful than the annual average alone.
Decatur's frost-free season lasts about 179 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Decatur coldest normal
January
The monthly mean of 26°F (-4°C) sits near freezing, so cold nights and above-freezing afternoons share the same month.
-
2. Decatur typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Decatur snow peak
January
Decatur averages 28.1 inches of snow a year, with January the snowiest month on the normals.
Questions about Decatur's climate
How much snow does Decatur get? ▼
How cold does Decatur get in winter? ▼
How much energy does heating and cooling require in Decatur? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Decatur's primary station: DECATUR 1 N (USC00122096). 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 1817074). Match rule for Decatur: 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 Decatur 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.