Mellette, SD 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 Mellette's primary NOAA station, MELLETTE 4 W.
The climate verdict for Mellette
Winter sets the terms in Mellette, South Dakota. A pronounced 59.5°F seasonal swing and heating demand above twice the cooling total frame an annual average of 43°F. At 49/100 (moderate) the climate comfort score falls in the bottom third of the station-mapped U.S. score corpus, exceeding only 18% of scores.
- 43°F
- annual average temperature (NOAA normal)
- 49/100
- comfort score, above 18% of station-mapped location scores
- 23.0"
- annual precipitation · 43" snow
- 139 days
- frost-free growing season
Mellette: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USC00395456 · Mellette, SD 43°F mean · 23.0" precip
TEMP-COOL · RANK-COOL · PHOTO-FINISH · PRCP-DRY · SWING-WIDE · COMF-LOW · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 43°F
- RANK-COOL #755
- PHOTO-FINISH ≈ White Rock Dam
- PRCP-DRY 23.0"
- SWING-WIDE 60°F
- COMF-LOW 49/100
- LOAD-HEAT 8,603 HDD
- STN-1 USC00395456
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: White Rock Dam, MN (+ 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 SD station list.
- Mellette (this station) 43°F
- Cold Roscoe, SD 43°F
- Hot Columbia, SD 43°F
- Near White Rock Dam, MN 43°F
- Near Webster, SD 43°F
Climate Living Index · Mellette
Mellette: 24/100 · grade F
Mellette publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Mellette, not an official NOAA rating. Rankings still use Comfort Score 49/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 23.0 in · 12.0 from 35 in | 58/100 · C |
| Snowfall burden | 43.4 inches/year | 25/100 · F |
| Normal heat + freeze calendar | 190 calendar days | 19/100 · F |
| Frost-free season | 139 days/year | 18/100 · F |
| Annual temperature balance | 42.8°F · 24.7° from 67.5°F | 12/100 · F |
Mellette · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Mellette is a continental Köppen climate: Dfb
Coldest-month mean 11.8°F and warmest-month mean 71.3°F place this station in continental, no dry season, warm summer climates (Dfb). Class Dfb is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, warm summer.
- Köppen code
- Dfb
- Group
- Continental
- Warmest month
- 71.3°F
- Coldest month
- 11.8°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 Mellette sits across the climate record
Three NOAA fields for Mellette's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- Cooler than 89%
- Among 6,861 stations, Mellette sits in the cooler third of annual means.
- Annual precipitation
- 32nd percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 97%
- Warmest-to-coldest month gap for Mellette is large versus 6,861 complete station-years.
How Mellette compares across U.S. station-mapped locations
Mellette's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
49 18th percentile score exceeds 18% 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%). This entry sits in this band.
- 50–60: 1,329 station-mapped locations (21%). Above this entry.
- 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
Mellette's measured station temperature trend
MethodologyAcross 93 complete annual observations from 1897 to 2016, MELLETTE 4 W warmed at a fitted rate of 0.12°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Mellette primary station fitted change +0.12 °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 | 22°F (-5°C) | 1°F (-17°C) | 12°F (-11°C) | 0.6" | 8.5" | 31.0 | 0.0 |
| February | 27°F (-3°C) | 5°F (-15°C) | 16°F (-9°C) | 0.7" | 7.8" | 27.7 | 0.0 |
| March | 40°F (4°C) | 17°F (-8°C) | 29°F (-2°C) | 0.9" | 5.6" | 28.3 | 0.0 |
| April | 56°F (13°C) | 29°F (-2°C) | 43°F (6°C) | 2.1" | 5.4" | 17.4 | 0.1 |
| May | 69°F (20°C) | 43°F (6°C) | 56°F (13°C) | 3.3" | 0.0" | 3.1 | 0.7 |
| June | 79°F (26°C) | 54°F (12°C) | 66°F (19°C) | 3.5" | 0.0" | 0.0 | 2.3 |
| July | 84°F (29°C) | 59°F (15°C) | 71°F (22°C) | 3.5" | 0.0" | 0.0 | 6.6 |
| August | 82°F (28°C) | 55°F (13°C) | 69°F (20°C) | 2.5" | 0.0" | 0.0 | 4.6 |
| September | 74°F (23°C) | 45°F (7°C) | 60°F (15°C) | 2.4" | 0.0" | 1.8 | 2.1 |
| October | 59°F (15°C) | 32°F (0°C) | 45°F (7°C) | 2.1" | 0.9" | 14.5 | 0.2 |
| November | 42°F (5°C) | 19°F (-7°C) | 30°F (-1°C) | 0.7" | 5.9" | 27.6 | 0.0 |
| December | 28°F (-2°C) | 7°F (-14°C) | 18°F (-8°C) | 0.7" | 9.3" | 31.0 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 84°F around July 20, short of 90°F on every date, while 190 dates carry a normal low at or below freezing, the coldest 1°F near January 21.
The freezing stretch
The normal low stays at or below 32°F into April 22, then returns to freezing around October 16, covering 190 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 June 2, when 37% of years recorded at least a hundredth of an inch. The driest is November 21 at 16%. Summed across the calendar, that is about 88 wet dates a year.
The widest day
September 21 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 Mellette.
Where Mellette Stands Nationally
Freezing is routine here by normals standards — the normal low reaches 32°F or colder on about 190 nights a year, more than most ranked stations.
Mellette 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 and snowfall
Snow: 8.5"
5.8 days with precipitation
Snow: 7.8"
5.5 days with precipitation
Snow: 5.6"
5.6 days with precipitation
Snow: 5.4"
7.9 days with precipitation
10.9 days with precipitation
11.1 days with precipitation
8.8 days with precipitation
7.8 days with precipitation
7.0 days with precipitation
Snow: 0.9"
7.4 days with precipitation
Snow: 5.9"
4.7 days with precipitation
Snow: 9.3"
5.8 days with precipitation
Mellette runs a summer-peaked wet season
41% of Mellette'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 July at 3.5", on a wide 59.5°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: July, June, May, taking 45% of the annual total between them.
- Driest month: January at 0.6".
- Winter share: 8% 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 Mellette's precipitation splits across the calendar
About 88 days a year record measurable precipitation here, carrying 23.0" between them, or roughly 0.26 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 Mellette
Mellette averages 43.4 inches of snowfall a year, with December the snowiest month on the normals, spread across roughly 22 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: 43.4 inches of depth.
- Days recording measurable snow: about 22 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 19% 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
September 27
50% probability date
Last Spring Freeze
May 11
50% probability date
Growing Season
139 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
8,603
Higher = more heating needed
Cooling Degree Days
532
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside SD closest to Mellette 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 (43°F here).
- Cooperstown, NY 43°F · 0.0°F off
- Craig, CO 43°F · 0.0°F off
- Denton, MT 43°F · 0.0°F off
- Elfin Cove, AK 43°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (23.0" here), excluding temperature-peer places.
- Matador, TX 23.0" · 0.0" off
- Ashland, KS 23.0" · 0.0" off
- Junction, TX 23.0" · 0.1" off
- Broken Bow, NE 23.0" · 0.1" off
Snow and freeze rhythm
When cold and snow define Mellette
heating led · moderate · high swing
Winter and seasonal range jointly define this record. Mellette logs 8,603 heating degree days, more than twice its 532 cooling total, while the typical coldest-to-warmest-month gap reaches 59.5°F. The annual mean therefore compresses two materially different seasons.
Only about 139 days are frost-free in a normal year. That short interval is consistent with the cold-season signal, but the measure does not predict the exact first or last freeze in any one year.
-
1. Mellette coldest normal
January
Averaging 12°F (-11°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Mellette typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Mellette snow peak
December
Mellette averages 43.4 inches of snow a year, with December the snowiest month on the normals.
Questions about Mellette's climate
How much snow does Mellette get? ▼
How cold does Mellette get in winter? ▼
How much energy does heating and cooling require in Mellette? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Mellette's primary station: MELLETTE 4 W (USC00395456). 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 4641860). Match rule for Mellette: 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 Mellette 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.