Mellette, South Dakota climate: Normal weather by month, frost dates and records
Mellette's normal year runs from 1°F January nights to 84°F July afternoons, with 23.0 inches of precipitation and 43 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.0°C, January lows of −17°C, July highs of 29°C, 583 mm of precipitation a year.
- NOAA stationMellette (4 mi W)
- Station IDUSC00395456
- Location45.16°N 98.58°W
- Elevation1,296 ft (395 m)
- Population193
On October 23, the normal high in Mellette is 55°F and the normal low 29°F, and the chance of measurable rain or snow is 21%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Mellette.
- Jan 22° 1°
- Feb 27° 5°
- Mar 40° 17°
- Apr 56° 29°
- May 69° 43°
- Jun 79° 54°
- Jul 84° 59°
- Aug 82° 55°
- Sep 74° 45°
- Oct 59° 32°
- Nov 42° 19°
- Dec 28° 7°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Mellette each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 1°F. The most precipitation falls in July (3.51 in), the least in January (0.57 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 22°F | 1°F | 11.8°F | 0.57 | 8.5 | 6 | <1 | 31 | 9 h 10 min |
| February | 27°F | 5°F | 16.2°F | 0.65 | 7.8 | 6 | <1 | 28 | 10 h 20 min |
| March | 40°F | 17°F | 28.6°F | 0.90 | 5.6 | 6 | <1 | 28 | 11 h 50 min |
| April | 56°F | 29°F | 42.5°F | 2.11 | 5.4 | 8 | <1 | 17 | 13 h 30 min |
| May | 69°F | 43°F | 55.7°F | 3.34 | 0.0 | 11 | 1 | 3 | 14 h 50 min |
| June | 79°F | 54°F | 66.3°F | 3.47 | 0.0 | 11 | 2 | <1 | 15 h 40 min |
| July | 84°F | 59°F | 71.3°F | 3.51 | 0.0 | 9 | 7 | <1 | 15 h 20 min |
| August | 82°F | 55°F | 68.5°F | 2.54 | 0.0 | 8 | 5 | <1 | 14 h 10 min |
| September | 74°F | 45°F | 59.5°F | 2.35 | 0.0 | 7 | 2 | 2 | 12 h 40 min |
| October | 59°F | 32°F | 45.1°F | 2.12 | 0.9 | 7 | <1 | 15 | 11 h |
| November | 42°F | 19°F | 30.2°F | 0.73 | 5.9 | 5 | <1 | 28 | 9 h 40 min |
| December | 28°F | 7°F | 17.5°F | 0.67 | 9.3 | 6 | <1 | 31 | 8 h 50 min |
| Year (annual) | 55°F | 31°F | 42.8°F | 22.96 | 43.4 | 88 | 16 | 182 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −5°C | −17°C | −11.2°C | 14 mm | 22 cm |
| February | −3°C | −15°C | −8.8°C | 17 mm | 20 cm |
| March | 4°C | −8°C | −1.9°C | 23 mm | 14 cm |
| April | 13°C | −2°C | 5.8°C | 54 mm | 14 cm |
| May | 20°C | 6°C | 13.2°C | 85 mm | 0 cm |
| June | 26°C | 12°C | 19.1°C | 88 mm | 0 cm |
| July | 29°C | 15°C | 21.8°C | 89 mm | 0 cm |
| August | 28°C | 13°C | 20.3°C | 65 mm | 0 cm |
| September | 23°C | 7°C | 15.3°C | 60 mm | 0 cm |
| October | 15°C | 0°C | 7.3°C | 54 mm | 2 cm |
| November | 5°C | −7°C | −1.0°C | 19 mm | 15 cm |
| December | −2°C | −14°C | −8.1°C | 17 mm | 24 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00395456; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Mellette?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (7).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00395456.
When is the last frost in Mellette?
In Mellette, the last spring frost (32°F) comes after May 11 in half of years and after May 23 in one year in ten; the first autumn frost comes before September 27 in half of years and before September 15 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- May 111 year in 10 after May 23; 9 in 10 after April 29
- First autumn frost, half of years before
- September 271 year in 10 before September 15; 9 in 10 before October 7
NOAA puts the median frost-free season at 137 days, and the season without a hard freeze (28°F) at 154 days.
A hard freeze (28°F) comes after May 2 in half of springs and before October 4 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Mellette in zone 4a in ZIP code 57461, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Mellette's NOAA station is in zone 4a: the coldest night of a typical year reaches −26°F (25 complete years).
Frost dates for every NOAA station in South Dakota · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00395456; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Mellette?
In a normal year in Mellette, 16 days a year reach 90°F (1 of them 100°F or more), 182 nights fall to 32°F or colder and 88 days bring measurable precipitation.
- Days at 90°F or more
- 16a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 182a normal year
- Days that stay below freezing
- 77high of 32°F or less
- Days with 0.01 inch of precipitation
- 88a normal year
- Days with 1 inch of snow or more
- 16a normal year
The highest temperature in this station's record (since 1895) is 114°F, on August 13, 1965; the lowest is −45°F, on January 12, 1912.
The wettest calendar year on that record is 1998, with 31.48 in; the snowiest season is 1996–97, with 106.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00395456; records: ACIS (NOAA Regional Climate Centers), station USC00395456. Records use complete months only; a month missing more than three days is left out.
How sunny is Mellette?
Over a year 78% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Mellette, 4.1 kWh per square metre a day. July is the sunniest month (85%) and December the cloudiest (70%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 79% | 1.9 |
| February | 81% | 3.0 |
| March | 75% | 4.0 |
| April | 73% | 5.0 |
| May | 73% | 5.8 |
| June | 79% | 6.5 |
| July | 85% | 6.8 |
| August | 83% | 5.6 |
| September | 79% | 4.3 |
| October | 72% | 2.8 |
| November | 73% | 1.9 |
| December | 70% | 1.4 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Mellette need?
A normal year in Mellette brings 8,603 heating degree days, 60% more than the median U.S. place (5,373), and 532 cooling degree days, 41% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,360 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,651 | 0 |
| February | 1,368 | 0 |
| March | 1,130 | 0 |
| April | 676 | 1 |
| May | 311 | 21 |
| June | 66 | 107 |
| July | 17 | 212 |
| August | 39 | 147 |
| September | 210 | 43 |
| October | 619 | 2 |
| November | 1,044 | 0 |
| December | 1,474 | 0 |
| Year (annual) | 8,603 | 532 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00395456. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Mellette been warmer than normal lately?
Over 93 complete years from 1897 to 2016, the station's annual mean temperature rose at a fitted 2.1°F per century (+0.12°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Mellette's climate compare?
Mellette is warmer than 9 of the other 99 places with their own NOAA record in South Dakota, and wetter than 54. Across the 7,247 U.S. stations with normals, its annual mean of 42.8°F is warmer than 12%.
In the Köppen classification computed from these normals, Mellette is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Mellette share this climate record?
3 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Northville, SD134 people · 0 mi E
- Mansfield, SD29 people · 6 mi N
- Chelsea, SD19 people · 8 mi W
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Mellette's climate
What is the coldest month in Mellette?
January, with a normal high of 22°F and a normal low of 1°F. The warmest is July (84°F by day, 59°F at night).
Does it snow in Mellette?
Yes: 43 inches in a normal year, falling on 22 days with 0.1 inch or more, the most in December (9.3 inches).
What is the rainiest month in Mellette?
July, with 3.51 in of precipitation in a normal year; the driest is January with 0.57 in.
What plant hardiness zone is Mellette in?
The USDA's 2023 map puts Mellette in zone 4a in ZIP code 57461, the nearest ZIP area. By the same method at Mellette's NOAA station, the coldest night of a typical year reaches −26°F (25 years, 1991-2020): zone 4a.
How late can frost come in Mellette?
In half of years the last 32°F night comes after May 11; in one year in ten it comes after May 23. Waiting until May 23 leaves about a one-in-ten chance of a later frost.
Nearby and next
- South Dakota climateThe statewide normals and every place in the state
- Redfield, SD20 miles from this station, 44.0°F a year
- Aberdeen, SD22 miles from this station, 44.1°F a year
- Conde, SD24 miles from this station, 43.6°F a year
- Turton, SD25 miles from this station, 44.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made