Bullfrog Basin, Utah climate: Climate normals at a NOAA weather station
Bullfrog Basin's normal year runs from 26°F December nights to 100°F July afternoons, with 6.4 inches of precipitation and 4 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 15.3°C, December lows of −4°C, July highs of 38°C, 164 mm of precipitation a year.
- NOAA stationBullfrog Basin
- Station IDUSC00421020
- Location37.53°N 110.72°W
- Elevation3,822 ft (1,165 m)
On October 23, the normal high in Bullfrog Basin is 70°F and the normal low 43°F, and the chance of measurable rain or snow is 11%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Bullfrog Basin.
- Jan 46° 26°
- Feb 53° 30°
- Mar 63° 36°
- Apr 72° 44°
- May 82° 53°
- Jun 94° 64°
- Jul 100° 71°
- Aug 97° 69°
- Sep 88° 60°
- Oct 74° 46°
- Nov 58° 34°
- Dec 46° 26°
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 Bullfrog Basin each month?
July is the warmest month, with normal highs of 100°F; December the coldest, with normal lows of 26°F. The most precipitation falls in September (0.81 in), the least in June (0.15 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 46°F | 26°F | 36.1°F | 0.63 | 0.9 | 4 | <1 | 28 | 9 h 50 min |
| February | 53°F | 30°F | 41.2°F | 0.53 | 0.8 | 4 | <1 | 19 | 10 h 50 min |
| March | 63°F | 36°F | 49.9°F | 0.65 | 0.3 | 4 | <1 | 7 | 11 h 50 min |
| April | 72°F | 44°F | 57.7°F | 0.34 | 0.0 | 3 | <1 | 1 | 13 h 10 min |
| May | 82°F | 53°F | 67.6°F | 0.44 | 0.0 | 3 | 8 | <1 | 14 h 10 min |
| June | 94°F | 64°F | 79.0°F | 0.15 | 0.0 | 1 | 24 | <1 | 14 h 40 min |
| July | 100°F | 71°F | 85.5°F | 0.59 | 0.0 | 3 | 30 | <1 | 14 h 30 min |
| August | 97°F | 69°F | 82.5°F | 0.54 | 0.0 | 4 | 28 | <1 | 13 h 40 min |
| September | 88°F | 60°F | 73.7°F | 0.81 | 0.0 | 4 | 15 | <1 | 12 h 30 min |
| October | 74°F | 46°F | 59.8°F | 0.81 | 0.0 | 4 | 1 | 1 | 11 h 20 min |
| November | 58°F | 34°F | 46.1°F | 0.53 | 0.2 | 3 | <1 | 12 | 10 h 10 min |
| December | 46°F | 26°F | 35.9°F | 0.42 | 1.8 | 4 | <1 | 28 | 9 h 40 min |
| Year (annual) | 73°F | 47°F | 59.6°F | 6.44 | 4.0 | 40 | 106 | 95 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 8°C | −3°C | 2.3°C | 16 mm | 2 cm |
| February | 12°C | −1°C | 5.1°C | 13 mm | 2 cm |
| March | 17°C | 2°C | 9.9°C | 17 mm | 1 cm |
| April | 22°C | 7°C | 14.3°C | 9 mm | 0 cm |
| May | 28°C | 12°C | 19.8°C | 11 mm | 0 cm |
| June | 34°C | 18°C | 26.1°C | 4 mm | 0 cm |
| July | 38°C | 22°C | 29.7°C | 15 mm | 0 cm |
| August | 36°C | 20°C | 28.1°C | 14 mm | 0 cm |
| September | 31°C | 15°C | 23.2°C | 21 mm | 0 cm |
| October | 23°C | 8°C | 15.4°C | 21 mm | 0 cm |
| November | 15°C | 1°C | 7.8°C | 13 mm | 1 cm |
| December | 8°C | −4°C | 2.2°C | 11 mm | 5 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00421020; 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 Bullfrog Basin?
Normal highs sit between 65°F and 85°F in April, May and October. Of those, May has the fewest days with rain (3).
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 USC00421020.
When is the last frost at Bullfrog Basin?
In Bullfrog Basin, the last spring frost (32°F) comes after March 25 in half of years and after April 12 in one year in ten; the first autumn frost comes before November 10 in half of years and before October 26 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
- March 251 year in 10 after April 12; 9 in 10 after March 8
- First autumn frost, half of years before
- November 101 year in 10 before October 26; 9 in 10 before November 20
NOAA puts the median frost-free season at 227 days, and the season without a hard freeze (28°F) at 255 days.
A hard freeze (28°F) comes after March 6 in half of springs and before November 20 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Bullfrog Basin in zone 8a in ZIP code 84533, 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 8a: the coldest night of a typical year reaches 15°F (20 complete years).
Frost dates for every NOAA station in Utah · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00421020; 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 Bullfrog Basin?
In a normal year in Bullfrog Basin, 106 days a year reach 90°F (38 of them 100°F or more), 95 nights fall to 32°F or colder and 40 days bring measurable precipitation.
- Days at 90°F or more
- 106a normal year
- Days at 100°F or more
- 38a normal year
- Nights at 32°F or colder
- 95a normal year
- Days that stay below freezing
- 2high of 32°F or less
- Days with 0.01 inch of precipitation
- 40a normal year
- Days with 1 inch of snow or more
- 2a normal year
The highest temperature in this station's record (since 1967) is 114°F, on July 11, 2021; the lowest is 3°F, on January 7, 1971.
The wettest calendar year on that record is 1972, with 10.49 in; the snowiest season is 1978–79, with 27.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00421020; records: ACIS (NOAA Regional Climate Centers), station USC00421020. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Bullfrog Basin?
Over a year 88% of the sunlight that would reach the ground under clear skies gets through the clouds at Bullfrog Basin, 5.5 kWh per square metre a day. June is the sunniest month (93%) and December the cloudiest (78%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 79% | 2.8 |
| February | 80% | 3.8 |
| March | 86% | 5.4 |
| April | 87% | 6.7 |
| May | 88% | 7.7 |
| June | 93% | 8.4 |
| July | 90% | 7.6 |
| August | 89% | 6.8 |
| September | 91% | 5.9 |
| October | 89% | 4.5 |
| November | 86% | 3.2 |
| December | 78% | 2.5 |
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 many heating and cooling degree days does Bullfrog Basin record?
A normal year at Bullfrog Basin brings 4,009 heating degree days, 25% fewer than the median U.S. place (5,373), and 2,069 cooling degree days, 2.3 times the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,917 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 894 | 0 |
| February | 666 | 0 |
| March | 470 | 1 |
| April | 233 | 14 |
| May | 66 | 146 |
| June | 4 | 423 |
| July | 0 | 635 |
| August | 0 | 544 |
| September | 14 | 275 |
| October | 193 | 30 |
| November | 566 | 0 |
| December | 903 | 0 |
| Year (annual) | 4,009 | 2,069 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00421020. 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 Bullfrog Basin been warmer than normal?
2025 averaged 61.1°F, 1.5°F above the 1991-2020 normal of 59.6°F. 1 of the 2 complete years since 2023 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2023 | 59.2°F | −0.4°F | 5.25 | 14.0 |
| 2025 | 61.1°F | +1.5°F | – | 0.0 |
Over 32 complete years from 1968 to 2025, the station's annual mean temperature rose at a fitted 5.8°F per century (+0.32°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00421020; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Bullfrog Basin's climate compare?
Bullfrog Basin is warmer than 95 of the 97 places with their own NOAA record in Utah, and wetter than 4. Across the 7,247 U.S. stations with normals, its annual mean of 59.6°F is warmer than 74%.
In the Köppen classification computed from these normals, Bullfrog Basin is BWk: cold desert. 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 Bullfrog Basin share this climate record?
Halls Crossing 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.
- Halls Crossing, UT0 people · 5 mi SE
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 Bullfrog Basin's climate
What is the coldest month at Bullfrog Basin?
December, with a normal high of 46°F and a normal low of 26°F. The warmest is July (100°F by day, 71°F at night).
Does it snow at Bullfrog Basin?
Yes: 4 inches in a normal year, falling on 3 days with 0.1 inch or more, the most in December (1.8 inches).
What is the rainiest month at Bullfrog Basin?
September, with 0.81 in of precipitation in a normal year; the driest is June with 0.15 in.
What plant hardiness zone is Bullfrog Basin in?
The USDA's 2023 map puts Bullfrog Basin in zone 8a in ZIP code 84533, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 15°F (20 years, 1991-2020): zone 8a.
How late can frost come at Bullfrog Basin?
In half of years the last 32°F night comes after March 25; in one year in ten it comes after April 12. Waiting until April 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Utah climateThe statewide normals and every place in the state
- Hite Ranger Station, UT30 miles from this station, 61.9°F a year
- Natural Bridges National Monument, UT41 miles from this station, 50.7°F a year
- Boulder, UT47 miles from this station, 50.3°F a year
- Valley Of The Gods, UT47 miles from this station, 57.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made