Heart Butte Dam, North Dakota climate: Climate normals at a NOAA weather station
Heart Butte Dam's normal year runs from 3°F January nights to 84°F July afternoons, with 16.8 inches of precipitation and 38 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 5.9°C, January lows of −16°C, July highs of 29°C, 426 mm of precipitation a year.
- NOAA stationHeart Butte Dam
- Station IDUSC00324091
- Location46.59°N 101.81°W
- Elevation2,134 ft (650 m)
On October 23, the normal high in Heart Butte Dam is 53°F and the normal low 28°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 Heart Butte Dam.
- Jan 25° 3°
- Feb 29° 6°
- Mar 41° 17°
- Apr 55° 29°
- May 66° 41°
- Jun 76° 52°
- Jul 84° 57°
- Aug 83° 55°
- Sep 73° 45°
- Oct 57° 32°
- Nov 41° 19°
- Dec 30° 9°
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 Heart Butte Dam each month?
July is the warmest month, with normal highs of 84°F; January the coldest, with normal lows of 3°F. The most precipitation falls in June (3.28 in), the least in February (0.44 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 25°F | 3°F | 13.8°F | 0.48 | 7.3 | 6 | <1 | 31 | 9 h |
| February | 29°F | 6°F | 17.6°F | 0.44 | 5.3 | 6 | <1 | 28 | 10 h 20 min |
| March | 41°F | 17°F | 29.1°F | 0.71 | 5.3 | 7 | <1 | 29 | 11 h 50 min |
| April | 55°F | 29°F | 41.7°F | 1.39 | 4.7 | 8 | <1 | 20 | 13 h 30 min |
| May | 66°F | 41°F | 53.9°F | 2.15 | 0.6 | 11 | <1 | 5 | 15 h |
| June | 76°F | 52°F | 64.0°F | 3.28 | 0.0 | 11 | 2 | <1 | 15 h 50 min |
| July | 84°F | 57°F | 70.4°F | 2.66 | 0.0 | 9 | 8 | <1 | 15 h 30 min |
| August | 83°F | 55°F | 68.8°F | 1.74 | 0.0 | 7 | 8 | <1 | 14 h 20 min |
| September | 73°F | 45°F | 58.9°F | 1.61 | 0.0 | 7 | 2 | 2 | 12 h 40 min |
| October | 57°F | 32°F | 44.2°F | 1.31 | 2.5 | 7 | <1 | 16 | 11 h |
| November | 41°F | 19°F | 29.9°F | 0.58 | 6.2 | 5 | <1 | 28 | 9 h 30 min |
| December | 30°F | 9°F | 19.0°F | 0.44 | 5.8 | 6 | <1 | 31 | 8 h 40 min |
| Year (annual) | 55°F | 30°F | 42.6°F | 16.79 | 37.7 | 91 | 20 | 189 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −4°C | −16°C | −10.1°C | 12 mm | 19 cm |
| February | −2°C | −14°C | −8.0°C | 11 mm | 13 cm |
| March | 5°C | −8°C | −1.6°C | 18 mm | 13 cm |
| April | 13°C | −2°C | 5.4°C | 35 mm | 12 cm |
| May | 19°C | 5°C | 12.2°C | 55 mm | 2 cm |
| June | 25°C | 11°C | 17.8°C | 83 mm | 0 cm |
| July | 29°C | 14°C | 21.3°C | 68 mm | 0 cm |
| August | 28°C | 13°C | 20.4°C | 44 mm | 0 cm |
| September | 23°C | 7°C | 14.9°C | 41 mm | 0 cm |
| October | 14°C | 0°C | 6.8°C | 33 mm | 6 cm |
| November | 5°C | −7°C | −1.2°C | 15 mm | 16 cm |
| December | −1°C | −13°C | −7.2°C | 11 mm | 15 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00324091; 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 Heart Butte Dam?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August 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 USC00324091.
When is the last frost at Heart Butte Dam?
In Heart Butte Dam, the last spring frost (32°F) comes after May 14 in half of years and after May 28 in one year in ten; the first autumn frost comes before September 29 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 141 year in 10 after May 28; 9 in 10 after May 3
- First autumn frost, half of years before
- September 291 year in 10 before September 16; 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 153 days.
A hard freeze (28°F) comes after May 5 in half of springs and before October 6 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Heart Butte Dam in zone 4a in ZIP code 58533, 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 4a: the coldest night of a typical year reaches −28°F (25 complete years).
Frost dates for every NOAA station in North Dakota · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00324091; 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 Heart Butte Dam?
In a normal year in Heart Butte Dam, 20 days a year reach 90°F (2 of them 100°F or more), 189 nights fall to 32°F or colder and 91 days bring measurable precipitation.
- Days at 90°F or more
- 20a normal year
- Days at 100°F or more
- 2a normal year
- Nights at 32°F or colder
- 189a normal year
- Days that stay below freezing
- 73high of 32°F or less
- Days with 0.01 inch of precipitation
- 91a normal year
- Days with 1 inch of snow or more
- 16a normal year
The highest temperature in this station's record (since 1984) is 111°F, on July 30, 2006; the lowest is −42°F, on February 19, 2025.
The wettest calendar year on that record is 2013, with 27.71 in; the snowiest season is 2008–09, with 75.4 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00324091; records: ACIS (NOAA Regional Climate Centers), station USC00324091. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Heart Butte Dam?
Over a year 77% of the sunlight that would reach the ground under clear skies gets through the clouds at Heart Butte Dam, 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 many heating and cooling degree days does Heart Butte Dam record?
A normal year at Heart Butte Dam brings 8,599 heating degree days, 60% more than the median U.S. place (5,373), and 477 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 2,214 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,589 | 0 |
| February | 1,326 | 0 |
| March | 1,113 | 0 |
| April | 700 | 1 |
| May | 359 | 13 |
| June | 99 | 71 |
| July | 24 | 191 |
| August | 43 | 162 |
| September | 222 | 39 |
| October | 648 | 2 |
| November | 1,053 | 0 |
| December | 1,426 | 0 |
| Year (annual) | 8,599 | 477 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00324091. 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.
Have recent years at Heart Butte Dam been warmer than normal?
2021 averaged 44.5°F, 1.9°F above the 1991-2020 normal of 42.6°F.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 44.5°F | +1.9°F | 12.54 | – |
Over 33 complete years from 1985 to 2021, the station's annual mean temperature rose at a fitted 1.7°F per century (+0.10°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00324091; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Heart Butte Dam's climate compare?
Heart Butte Dam is warmer than 74 of the 92 places with their own NOAA record in North Dakota, and wetter than 12. Across the 7,247 U.S. stations with normals, its annual mean of 42.6°F is warmer than 11%.
In the Köppen classification computed from these normals, Heart Butte Dam 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.
Questions about Heart Butte Dam's climate
What is the coldest month at Heart Butte Dam?
January, with a normal high of 25°F and a normal low of 3°F. The warmest is July (84°F by day, 57°F at night).
Does it snow at Heart Butte Dam?
Yes: 38 inches in a normal year, falling on 28 days with 0.1 inch or more, the most in January (7.3 inches).
What is the rainiest month at Heart Butte Dam?
June, with 3.28 in of precipitation in a normal year; the driest is February with 0.44 in.
What plant hardiness zone is Heart Butte Dam in?
The USDA's 2023 map puts Heart Butte Dam in zone 4a in ZIP code 58533, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −28°F (25 years, 1991-2020): zone 4a.
How late can frost come at Heart Butte Dam?
In half of years the last 32°F night comes after May 14; in one year in ten it comes after May 28. Waiting until May 28 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
- Carson, ND16 miles from this station, 42.2°F a year
- Almont, ND17 miles from this station, 43.1°F a year
- Hebron, ND24 miles from this station, 41.5°F a year
- New Salem, ND25 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