Bison, South Dakota climate: Normal weather by month, frost dates and records
Bison's normal year runs from 10°F January nights to 86°F July afternoons, with 18.1 inches of precipitation and 40 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 7.6°C, January lows of −12°C, July highs of 30°C, 460 mm of precipitation a year.
- NOAA stationBison
- Station IDUSC00390701
- Location45.53°N 102.47°W
- Elevation2,780 ft (847 m)
- Population302
On October 22, the normal high in Bison is 56°F and the normal low 32°F, and the chance of measurable rain or snow is 12%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Bison.
- Jan 30° 10°
- Feb 33° 12°
- Mar 45° 22°
- Apr 57° 32°
- May 68° 43°
- Jun 78° 52°
- Jul 86° 59°
- Aug 86° 57°
- Sep 76° 48°
- Oct 60° 35°
- Nov 43° 23°
- Dec 32° 13°
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 Bison each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 10°F. The most precipitation falls in June (3.15 in), the least in December (0.44 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 30°F | 10°F | 19.7°F | 0.46 | 5.6 | 3 | <1 | 30 | 9 h |
| February | 33°F | 12°F | 22.6°F | 0.56 | 8.0 | 4 | <1 | 27 | 10 h 20 min |
| March | 45°F | 22°F | 33.4°F | 0.87 | 7.0 | 4 | <1 | 26 | 11 h 50 min |
| April | 57°F | 32°F | 44.4°F | 1.76 | 5.4 | 6 | <1 | 16 | 13 h 30 min |
| May | 68°F | 43°F | 55.4°F | 3.11 | 0.7 | 7 | 1 | 4 | 14 h 50 min |
| June | 78°F | 52°F | 65.2°F | 3.15 | 0.0 | 8 | 3 | <1 | 15 h 40 min |
| July | 86°F | 59°F | 72.4°F | 2.50 | 0.0 | 7 | 11 | <1 | 15 h 20 min |
| August | 86°F | 57°F | 71.3°F | 1.83 | 0.0 | 5 | 10 | <1 | 14 h 10 min |
| September | 76°F | 48°F | 61.9°F | 1.38 | 0.0 | 4 | 3 | 1 | 12 h 40 min |
| October | 60°F | 35°F | 47.2°F | 1.52 | 3.0 | 4 | <1 | 12 | 11 h |
| November | 43°F | 23°F | 33.0°F | 0.52 | 4.1 | 3 | <1 | 25 | 9 h 30 min |
| December | 32°F | 13°F | 22.4°F | 0.44 | 5.9 | 3 | <1 | 30 | 8 h 40 min |
| Year (annual) | 58°F | 34°F | 45.7°F | 18.10 | 39.7 | 57 | 28 | 171 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −1°C | −12°C | −6.8°C | 12 mm | 14 cm |
| February | 0°C | −11°C | −5.2°C | 14 mm | 20 cm |
| March | 7°C | −6°C | 0.8°C | 22 mm | 18 cm |
| April | 14°C | 0°C | 6.9°C | 45 mm | 14 cm |
| May | 20°C | 6°C | 13.0°C | 79 mm | 2 cm |
| June | 26°C | 11°C | 18.4°C | 80 mm | 0 cm |
| July | 30°C | 15°C | 22.4°C | 64 mm | 0 cm |
| August | 30°C | 14°C | 21.8°C | 46 mm | 0 cm |
| September | 25°C | 9°C | 16.6°C | 35 mm | 0 cm |
| October | 15°C | 2°C | 8.4°C | 39 mm | 8 cm |
| November | 6°C | −5°C | 0.6°C | 13 mm | 10 cm |
| December | 0°C | −11°C | −5.3°C | 11 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00390701; 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 Bison?
Normal highs sit between 65°F and 85°F in May, June and September. Of those, September has the fewest days with rain (4).
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 USC00390701.
When is the last frost in Bison?
In Bison, the last spring frost (32°F) comes after May 10 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 16 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 101 year in 10 after May 24; 9 in 10 after April 30
- First autumn frost, half of years before
- October 11 year in 10 before September 16; 9 in 10 before October 15
NOAA puts the median frost-free season at 144 days, and the season without a hard freeze (28°F) at 161 days.
A hard freeze (28°F) comes after May 1 in half of springs and before October 9 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Bison in zone 4b in ZIP code 57620, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Bison's NOAA station is in zone 4b: the coldest night of a typical year reaches −20°F (30 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 USC00390701; 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 Bison?
In a normal year in Bison, 28 days a year reach 90°F (3 of them 100°F or more), 171 nights fall to 32°F or colder and 57 days bring measurable precipitation.
- Days at 90°F or more
- 28a normal year
- Days at 100°F or more
- 3a normal year
- Nights at 32°F or colder
- 171a normal year
- Days that stay below freezing
- 59high of 32°F or less
- Days with 0.01 inch of precipitation
- 57a normal year
- Days with 1 inch of snow or more
- 14a normal year
The highest temperature in this station's record (since 1916) is 111°F, on July 10, 1936; the lowest is −42°F, on February 10, 1939.
The wettest calendar year on that record is 2019, with 28.33 in; the snowiest season is 2008–09, with 87.9 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00390701; records: ACIS (NOAA Regional Climate Centers), station USC00390701. Records use complete months only; a month missing more than three days is left out.
How sunny is Bison?
Over a year 79% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Bison, 4.2 kWh per square metre a day. July is the sunniest month (87%) and April the cloudiest (73%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 77% | 1.9 |
| February | 79% | 2.9 |
| March | 74% | 3.9 |
| April | 73% | 5.0 |
| May | 74% | 6.0 |
| June | 80% | 6.8 |
| July | 87% | 7.0 |
| August | 86% | 6.0 |
| September | 82% | 4.5 |
| October | 75% | 3.0 |
| November | 75% | 2.0 |
| December | 73% | 1.5 |
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 Bison need?
A normal year in Bison brings 7,612 heating degree days, 42% more than the median U.S. place (5,373), and 632 cooling degree days, 30% 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 2,564 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,406 | 0 |
| February | 1,187 | 0 |
| March | 978 | 0 |
| April | 618 | 1 |
| May | 312 | 16 |
| June | 80 | 85 |
| July | 14 | 243 |
| August | 22 | 217 |
| September | 158 | 66 |
| October | 556 | 4 |
| November | 962 | 0 |
| December | 1,320 | 0 |
| Year (annual) | 7,612 | 632 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00390701. 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 Bison been warmer than normal lately?
2025 averaged 46.7°F, 1.0°F above the 1991-2020 normal of 45.7°F. 4 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 48.8°F | +3.1°F | 14.39 | 9.1 |
| 2022 | 45.7°F | at normal | 12.33 | 49.4 |
| 2023 | 47.5°F | +1.8°F | 18.46 | 21.8 |
| 2024 | 48.4°F | +2.7°F | 12.68 | 15.8 |
| 2025 | 46.7°F | +1.0°F | 26.10 | 23.5 |
Over 57 complete years from 1933 to 2025, the station's annual mean temperature rose at a fitted 2.7°F per century (+0.15°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00390701; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Bison's climate compare?
Bison is warmer than 48 of the other 99 places with their own NOAA record in South Dakota, and wetter than 16. Across the 7,247 U.S. stations with normals, its annual mean of 45.7°F is warmer than 22%.
In the Köppen classification computed from these normals, Bison 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.
Questions about Bison's climate
What is the coldest month in Bison?
January, with a normal high of 30°F and a normal low of 10°F. The warmest is July (86°F by day, 59°F at night).
Does it snow in Bison?
Yes: 40 inches in a normal year, falling on 16 days with 0.1 inch or more, the most in February (8.0 inches).
What is the rainiest month in Bison?
June, with 3.15 in of precipitation in a normal year; the driest is December with 0.44 in.
What plant hardiness zone is Bison in?
The USDA's 2023 map puts Bison in zone 4b in ZIP code 57620, the nearest ZIP area. By the same method at Bison's NOAA station, the coldest night of a typical year reaches −20°F (30 years, 1991-2020): zone 4b.
How late can frost come in Bison?
In half of years the last 32°F night comes after May 10; 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
- Shadehill Reservoir, SD14 miles from this station, 44.1°F a year
- Lodgepole (5 mi SW), SD22 miles from this station, 41.1°F a year
- Lemmon, SD32 miles from this station, 45.7°F a year
- Glad Valley (2 mi W), SD33 miles from this station, 44.0°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made