Mandan, North Dakota climate: Normal weather by month, frost dates and records
Mandan's normal year runs from 3°F January nights to 83°F July afternoons, with 18.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.8°C, January lows of −16°C, July highs of 28°C, 466 mm of precipitation a year.
- NOAA stationMandan Experiment Station
- Station IDUSC00325479
- Location46.81°N 100.91°W
- Elevation1,750 ft (533 m)
- Population24,788
On October 14, the normal high in Mandan is 57°F and the normal low 33°F, and the chance of measurable rain or snow is 18%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Mandan.
- Jan 23° 3°
- Feb 27° 6°
- Mar 40° 18°
- Apr 54° 30°
- May 67° 43°
- Jun 76° 53°
- Jul 83° 58°
- Aug 82° 56°
- Sep 72° 46°
- Oct 56° 32°
- Nov 40° 19°
- Dec 27° 8°
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 Mandan each month?
July is the warmest month, with normal highs of 83°F; January the coldest, with normal lows of 3°F. The most precipitation falls in June (3.44 in), the least in January (0.38 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 23°F | 3°F | 12.6°F | 0.38 | 4 | <1 | 31 | 9 h |
| February | 27°F | 6°F | 16.7°F | 0.40 | 4 | <1 | 28 | 10 h 20 min |
| March | 40°F | 18°F | 29.0°F | 0.59 | 4 | <1 | 28 | 11 h 50 min |
| April | 54°F | 30°F | 42.3°F | 1.27 | 6 | <1 | 17 | 13 h 30 min |
| May | 67°F | 43°F | 54.5°F | 2.59 | 9 | <1 | 4 | 15 h |
| June | 76°F | 53°F | 64.5°F | 3.44 | 11 | 1 | <1 | 15 h 50 min |
| July | 83°F | 58°F | 70.3°F | 3.24 | 9 | 6 | <1 | 15 h 30 min |
| August | 82°F | 56°F | 68.7°F | 2.19 | 7 | 6 | <1 | 14 h 20 min |
| September | 72°F | 46°F | 59.0°F | 1.64 | 6 | 2 | 2 | 12 h 40 min |
| October | 56°F | 32°F | 44.1°F | 1.47 | 6 | <1 | 16 | 11 h |
| November | 40°F | 19°F | 29.5°F | 0.63 | 4 | <1 | 28 | 9 h 30 min |
| December | 27°F | 8°F | 17.9°F | 0.52 | 5 | <1 | 31 | 8 h 30 min |
| Year (annual) | 54°F | 31°F | 42.4°F | 18.36 | 75 | 15 | 184 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −5°C | −16°C | −10.8°C | 10 mm |
| February | −3°C | −14°C | −8.5°C | 10 mm |
| March | 4°C | −8°C | −1.7°C | 15 mm |
| April | 12°C | −1°C | 5.7°C | 32 mm |
| May | 19°C | 6°C | 12.5°C | 66 mm |
| June | 24°C | 12°C | 18.1°C | 87 mm |
| July | 28°C | 14°C | 21.3°C | 82 mm |
| August | 28°C | 13°C | 20.4°C | 56 mm |
| September | 22°C | 8°C | 15.0°C | 42 mm |
| October | 13°C | 0°C | 6.7°C | 37 mm |
| November | 4°C | −7°C | −1.4°C | 16 mm |
| December | −3°C | −13°C | −7.8°C | 13 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Bismarck (8 miles away), gets 51 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00325479; 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 Mandan?
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 (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 USC00325479.
When is the last frost in Mandan?
In Mandan, the last spring frost (32°F) comes after May 13 in half of years and after May 26 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 131 year in 10 after May 26; 9 in 10 after May 1
- First autumn frost, half of years before
- September 271 year in 10 before September 15; 9 in 10 before October 10
NOAA puts the median frost-free season at 136 days, and the season without a hard freeze (28°F) at 154 days.
A hard freeze (28°F) comes after May 3 in half of springs and before October 4 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Mandan in zone 4a in ZIP code 58505, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Mandan's NOAA station is in zone 4b: the coldest night of a typical year reaches −25°F (25 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in North Dakota · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00325479; 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 Mandan?
In a normal year in Mandan, 15 days a year reach 90°F (1 of them 100°F or more), 184 nights fall to 32°F or colder and 75 days bring measurable precipitation.
- Days at 90°F or more
- 15a normal year
- Days at 100°F or more
- 1a normal year
- Nights at 32°F or colder
- 184a normal year
- Days that stay below freezing
- 81high of 32°F or less
- Days with 0.01 inch of precipitation
- 75a normal year
The highest temperature in this station's record (since 1913) is 115°F, on July 6, 1936; the lowest is −46°F, on February 16, 1936.
The wettest calendar year on that record is 1986, with 25.52 in; the snowiest season is 1949–50, with 66.8 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00325479; records: ACIS (NOAA Regional Climate Centers), station USC00325479. Records use complete months only; a month missing more than three days is left out.
How sunny is Mandan?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Mandan, 4.0 kWh per square metre a day. July is the sunniest month (85%) and December the cloudiest (68%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 78% | 1.8 |
| February | 81% | 2.9 |
| March | 73% | 3.8 |
| April | 73% | 5.0 |
| May | 73% | 5.8 |
| June | 78% | 6.5 |
| July | 85% | 6.8 |
| August | 83% | 5.6 |
| September | 79% | 4.3 |
| October | 71% | 2.7 |
| November | 71% | 1.8 |
| December | 68% | 1.3 |
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 Mandan need?
A normal year in Mandan brings 8,674 heating degree days, 61% more than the median U.S. place (5,373), and 482 cooling degree days, 47% 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 2,242 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,624 | 0 |
| February | 1,351 | 0 |
| March | 1,118 | 0 |
| April | 683 | 1 |
| May | 340 | 16 |
| June | 93 | 78 |
| July | 24 | 188 |
| August | 44 | 157 |
| September | 223 | 42 |
| October | 649 | 1 |
| November | 1,065 | 0 |
| December | 1,460 | 0 |
| Year (annual) | 8,674 | 482 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00325479. 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 Mandan been warmer than normal lately?
2024 averaged 44.2°F, 1.8°F above the 1991-2020 normal of 42.4°F. 1 of the 2 complete years since 2023 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2023 | 42.4°F | at normal | 22.84 |
| 2024 | 44.2°F | +1.8°F | – |
Over 79 complete years from 1916 to 2024, the station's annual mean temperature rose at a fitted 3.5°F per century (+0.20°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00325479; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Mandan's climate compare?
Mandan is warmer than 70 of the other 91 places with their own NOAA record in North Dakota, and wetter than 29. Across the 7,247 U.S. stations with normals, its annual mean of 42.4°F is warmer than 10%.
In the Köppen classification computed from these normals, Mandan 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 Mandan share this climate record?
Harmon 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.
- Harmon, ND192 people · 10 mi N
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 Mandan's climate
What is the coldest month in Mandan?
January, with a normal high of 23°F and a normal low of 3°F. The warmest is July (83°F by day, 58°F at night).
Does it snow in Mandan?
Yes. NOAA publishes no 1991-2020 snowfall normal for Mandan's NOAA station; the nearest record that keeps one, Bismarck (8 miles away), records 51 inches of snow in a normal year.
What is the rainiest month in Mandan?
June, with 3.44 in of precipitation in a normal year; the driest is January with 0.38 in.
What plant hardiness zone is Mandan in?
The USDA's 2023 map puts Mandan in zone 4a in ZIP code 58505, the nearest ZIP area. By the same method at Mandan's NOAA station, the coldest night of a typical year reaches −25°F (25 years, 1991-2020): zone 4b.
How late can frost come in Mandan?
In half of years the last 32°F night comes after May 13; in one year in ten it comes after May 26. Waiting until May 26 leaves about a one-in-ten chance of a later frost.
Nearby and next
- North Dakota climateThe statewide normals and every place in the state
- Bismarck, ND7 miles from this station, 43.1°F a year
- Center, ND22 miles from this station, 42.6°F a year
- Wilton, ND25 miles from this station, 40.6°F a year
- New Salem, ND28 miles from this station, 41.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made