Longvalley, South Dakota climate: Climate normals at a NOAA weather station
Longvalley's normal year runs from 14°F January nights to 88°F July afternoons, with 21.0 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.4°C, January lows of −10°C, July highs of 31°C, 534 mm of precipitation a year.
- NOAA stationLongvalley
- Station IDUSC00394983
- Location43.46°N 101.50°W
- Elevation2,470 ft (753 m)
On October 22, the normal high in Longvalley is 60°F and the normal low 34°F, and the chance of measurable rain or snow is 19%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Longvalley.
- Jan 37° 14°
- Feb 40° 16°
- Mar 50° 25°
- Apr 60° 33°
- May 70° 44°
- Jun 81° 54°
- Jul 88° 61°
- Aug 88° 59°
- Sep 79° 49°
- Oct 63° 36°
- Nov 49° 25°
- Dec 39° 17°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like at Longvalley each month?
July is the warmest month, with normal highs of 88°F; January the coldest, with normal lows of 14°F. The most precipitation falls in May (3.78 in), the least in January (0.49 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 37°F | 14°F | 25.6°F | 0.49 | 5 | <1 | 29 | 9 h 20 min |
| February | 40°F | 16°F | 27.8°F | 0.74 | 6 | <1 | 25 | 10 h 30 min |
| March | 50°F | 25°F | 37.6°F | 1.48 | 7 | <1 | 24 | 11 h 50 min |
| April | 60°F | 33°F | 46.7°F | 2.48 | 10 | <1 | 13 | 13 h 20 min |
| May | 70°F | 44°F | 57.1°F | 3.78 | 10 | 1 | 3 | 14 h 40 min |
| June | 81°F | 54°F | 67.5°F | 3.13 | 10 | 5 | <1 | 15 h 20 min |
| July | 88°F | 61°F | 74.5°F | 2.69 | 8 | 15 | <1 | 15 h 10 min |
| August | 88°F | 59°F | 73.2°F | 1.78 | 6 | 14 | <1 | 14 h |
| September | 79°F | 49°F | 64.3°F | 1.50 | 6 | 5 | 1 | 12 h 30 min |
| October | 63°F | 36°F | 49.6°F | 1.76 | 7 | 1 | 10 | 11 h 10 min |
| November | 49°F | 25°F | 36.5°F | 0.63 | 5 | <1 | 24 | 9 h 40 min |
| December | 39°F | 17°F | 27.9°F | 0.55 | 5 | <1 | 29 | 9 h |
| Year (annual) | 62°F | 36°F | 49.0°F | 21.01 | 83 | 40 | 157 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 3°C | −10°C | −3.6°C | 12 mm |
| February | 4°C | −9°C | −2.3°C | 19 mm |
| March | 10°C | −4°C | 3.1°C | 38 mm |
| April | 16°C | 1°C | 8.2°C | 63 mm |
| May | 21°C | 7°C | 13.9°C | 96 mm |
| June | 27°C | 12°C | 19.7°C | 80 mm |
| July | 31°C | 16°C | 23.6°C | 68 mm |
| August | 31°C | 15°C | 22.9°C | 45 mm |
| September | 26°C | 10°C | 17.9°C | 38 mm |
| October | 17°C | 2°C | 9.8°C | 45 mm |
| November | 9°C | −4°C | 2.5°C | 16 mm |
| December | 4°C | −9°C | −2.3°C | 14 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Martin (23 miles away), gets 48 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00394983; 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.
Which months are mildest at Longvalley?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (6).
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 USC00394983.
When is the last frost at Longvalley?
In Longvalley, the last spring frost (32°F) comes after May 9 in half of years and after May 24 in one year in ten; the first autumn frost comes before October 1 in half of years and before September 17 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 91 year in 10 after May 24; 9 in 10 after April 26
- First autumn frost, half of years before
- October 11 year in 10 before September 17; 9 in 10 before October 15
NOAA puts the median frost-free season at 143 days, and the season without a hard freeze (28°F) at 162 days.
A hard freeze (28°F) comes after May 1 in half of springs and before October 11 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Longvalley in zone 5a in ZIP code 57547, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 5a: the coldest night of a typical year reaches −18°F (21 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 USC00394983; 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 at Longvalley?
In a normal year in Longvalley, 40 days a year reach 90°F (6 of them 100°F or more), 157 nights fall to 32°F or colder and 83 days bring measurable precipitation.
- Days at 90°F or more
- 40a normal year
- Days at 100°F or more
- 6a normal year
- Nights at 32°F or colder
- 157a normal year
- Days that stay below freezing
- 38high of 32°F or less
- Days with 0.01 inch of precipitation
- 83a normal year
The highest temperature in this station's record (since 1927) is 115°F, on July 29, 1933; the lowest is −35°F, on December 22, 1989.
The wettest calendar year on that record is 1995, with 27.68 in; the snowiest season is 1976–77, with 68.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00394983; records: ACIS (NOAA Regional Climate Centers), station USC00394983. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Longvalley?
Over a year 79% of the sunlight that would reach the ground under clear skies gets through the clouds at Longvalley, 4.3 kWh per square metre a day. July is the sunniest month (87%) and April the cloudiest (72%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 75% | 2.0 |
| February | 74% | 2.9 |
| March | 72% | 4.0 |
| April | 72% | 5.0 |
| May | 75% | 6.1 |
| June | 82% | 6.9 |
| July | 87% | 7.0 |
| August | 86% | 6.0 |
| September | 83% | 4.8 |
| October | 76% | 3.2 |
| November | 76% | 2.2 |
| December | 72% | 1.7 |
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 many heating and cooling degree days does Longvalley record?
A normal year at Longvalley brings 6,622 heating degree days, 23% more than the median U.S. place (5,373), and 841 cooling degree days, 7% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,951 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,220 | 0 |
| February | 1,040 | 0 |
| March | 850 | 0 |
| April | 552 | 3 |
| May | 272 | 26 |
| June | 56 | 133 |
| July | 8 | 302 |
| August | 14 | 270 |
| September | 121 | 100 |
| October | 486 | 8 |
| November | 854 | 0 |
| December | 1,150 | 0 |
| Year (annual) | 6,622 | 841 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00394983. 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.
How does Longvalley's climate compare?
Longvalley is warmer than 95 of the 100 places with their own NOAA record in South Dakota, and wetter than 34. Across the 7,247 U.S. stations with normals, its annual mean of 49.0°F is warmer than 36%.
In the Köppen classification computed from these normals, Longvalley is Dfa: continental, no dry season, hot 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 Longvalley share this climate record?
Wanblee has no NOAA station with 1991-2020 normals of its 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.
- Wanblee, SD744 people · 11 mi NW
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 Longvalley's climate
What is the coldest month at Longvalley?
January, with a normal high of 37°F and a normal low of 14°F. The warmest is July (88°F by day, 61°F at night).
Does it snow at Longvalley?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Martin (23 miles away), records 48 inches of snow in a normal year.
What is the rainiest month at Longvalley?
May, with 3.78 in of precipitation in a normal year; the driest is January with 0.49 in.
What plant hardiness zone is Longvalley in?
The USDA's 2023 map puts Longvalley in zone 5a in ZIP code 57547, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −18°F (21 years, 1991-2020): zone 5a.
How late can frost come at Longvalley?
In half of years the last 32°F night comes after May 9; in one year in ten it comes after May 24. Waiting until May 24 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
- Martin, SD23 miles from this station, 47.4°F a year
- Harrington, SD24 miles from this station, 47.6°F a year
- Cedar Butte, SD25 miles from this station, 48.9°F a year
- Interior, SD30 miles from this station, 50.4°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made