Diversion Dam, Wyoming climate: Climate normals at a NOAA weather station
Diversion Dam's normal year runs from 8°F December nights to 85°F July afternoons, with 9.8 inches of precipitation and 29 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.4°C, December lows of −13°C, July highs of 30°C, 248 mm of precipitation a year.
- NOAA stationDiversion Dam
- Station IDUSC00482595
- Location43.23°N 108.91°W
- Elevation5,578 ft (1,700 m)
On October 23, the normal high in Diversion Dam is 56°F and the normal low 27°F, and the chance of measurable rain or snow is 10%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Diversion Dam.
- Jan 36° 8°
- Feb 38° 11°
- Mar 49° 21°
- Apr 56° 28°
- May 65° 37°
- Jun 76° 44°
- Jul 85° 51°
- Aug 83° 49°
- Sep 73° 41°
- Oct 59° 30°
- Nov 45° 17°
- Dec 34° 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 at Diversion Dam each month?
July is the warmest month, with normal highs of 85°F; December the coldest, with normal lows of 8°F. The most precipitation falls in May (2.27 in), the least in January (0.16 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 36°F | 8°F | 22.1°F | 0.16 | 3.3 | 2 | <1 | 31 | 9 h 20 min |
| February | 38°F | 11°F | 24.6°F | 0.33 | 4.9 | 2 | <1 | 28 | 10 h 30 min |
| March | 49°F | 21°F | 34.8°F | 0.65 | 4.9 | 3 | <1 | 29 | 11 h 50 min |
| April | 56°F | 28°F | 42.1°F | 1.21 | 5.1 | 6 | <1 | 22 | 13 h 20 min |
| May | 65°F | 37°F | 51.0°F | 2.27 | 1.0 | 8 | <1 | 8 | 14 h 40 min |
| June | 76°F | 44°F | 59.9°F | 1.28 | 0.1 | 6 | 1 | 1 | 15 h 20 min |
| July | 85°F | 51°F | 67.8°F | 0.69 | 0.0 | 4 | 8 | <1 | 15 h 10 min |
| August | 83°F | 49°F | 66.0°F | 0.65 | 0.0 | 5 | 4 | <1 | 14 h |
| September | 73°F | 41°F | 56.8°F | 0.97 | 0.5 | 5 | <1 | 4 | 12 h 30 min |
| October | 59°F | 30°F | 44.3°F | 0.92 | 2.2 | 4 | <1 | 20 | 11 h 10 min |
| November | 45°F | 17°F | 30.9°F | 0.41 | 3.8 | 2 | <1 | 28 | 9 h 50 min |
| December | 34°F | 8°F | 21.1°F | 0.21 | 3.0 | 2 | <1 | 31 | 9 h |
| Year (annual) | 58°F | 29°F | 43.5°F | 9.75 | 28.8 | 48 | 14 | 200 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 2°C | −13°C | −5.5°C | 4 mm | 8 cm |
| February | 3°C | −12°C | −4.1°C | 8 mm | 12 cm |
| March | 9°C | −6°C | 1.6°C | 17 mm | 12 cm |
| April | 13°C | −2°C | 5.6°C | 31 mm | 13 cm |
| May | 18°C | 3°C | 10.6°C | 58 mm | 3 cm |
| June | 24°C | 7°C | 15.5°C | 33 mm | 0 cm |
| July | 30°C | 10°C | 19.9°C | 18 mm | 0 cm |
| August | 28°C | 9°C | 18.9°C | 17 mm | 0 cm |
| September | 23°C | 5°C | 13.8°C | 25 mm | 1 cm |
| October | 15°C | −1°C | 6.8°C | 23 mm | 6 cm |
| November | 7°C | −8°C | −0.6°C | 10 mm | 10 cm |
| December | 1°C | −13°C | −6.1°C | 5 mm | 8 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00482595; 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 Diversion Dam?
Normal highs sit between 65°F and 85°F in May, June, August and September. Of those, September has the fewest days with rain (5).
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 USC00482595.
When is the last frost at Diversion Dam?
In Diversion Dam, the last spring frost (32°F) comes after May 21 in half of years and after June 6 in one year in ten; the first autumn frost comes before September 20 in half of years and before September 5 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 211 year in 10 after June 6; 9 in 10 after May 7
- First autumn frost, half of years before
- September 201 year in 10 before September 5; 9 in 10 before October 4
NOAA puts the median frost-free season at 119 days, and the season without a hard freeze (28°F) at 143 days.
A hard freeze (28°F) comes after May 8 in half of springs and before October 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Diversion Dam in zone 5a in ZIP code 82516, the nearest ZIP area.
Frost dates for every NOAA station in Wyoming · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00482595; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Diversion Dam?
In a normal year in Diversion Dam, 14 days a year reach 90°F, 200 nights fall to 32°F or colder and 48 days bring measurable precipitation.
- Days at 90°F or more
- 14a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 200a normal year
- Days that stay below freezing
- 43high of 32°F or less
- Days with 0.01 inch of precipitation
- 48a normal year
- Days with 1 inch of snow or more
- 9a normal year
The highest temperature in this station's record (since 1920) is 100°F, on July 14, 1925; the lowest is −45°F, on January 17, 1930.
The wettest calendar year on that record is 2023, with 24.12 in; the snowiest season is 1996–97, with 50.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00482595; records: ACIS (NOAA Regional Climate Centers), station USC00482595. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Diversion Dam?
Over a year 80% of the sunlight that would reach the ground under clear skies gets through the clouds at Diversion Dam, 4.6 kWh per square metre a day. July is the sunniest month (87%) and December the cloudiest (71%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 77% | 2.1 |
| February | 77% | 3.1 |
| March | 76% | 4.3 |
| April | 75% | 5.5 |
| May | 76% | 6.4 |
| June | 84% | 7.5 |
| July | 87% | 7.3 |
| August | 86% | 6.4 |
| September | 85% | 5.1 |
| October | 78% | 3.4 |
| November | 76% | 2.3 |
| December | 71% | 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 Diversion Dam record?
A normal year at Diversion Dam brings 8,058 heating degree days, 50% more than the median U.S. place (5,373), and 238 cooling degree days, 74% 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 1,771 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,328 | 0 |
| February | 1,131 | 0 |
| March | 936 | 0 |
| April | 687 | 0 |
| May | 434 | 1 |
| June | 173 | 22 |
| July | 33 | 121 |
| August | 54 | 84 |
| September | 257 | 9 |
| October | 640 | 0 |
| November | 1,025 | 0 |
| December | 1,361 | 0 |
| Year (annual) | 8,058 | 238 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00482595. 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 Diversion Dam been warmer than normal?
2023 averaged 40.6°F, 2.9°F below the 1991-2020 normal of 43.5°F.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2023 | 40.6°F | −2.9°F | 24.12 | 42.4 |
Over 32 complete years from 1950 to 2023, the station's annual mean temperature rose at a fitted 0.8°F per century (+0.05°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00482595; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Diversion Dam's climate compare?
Diversion Dam is warmer than 27 of the 71 places with their own NOAA record in Wyoming, and wetter than 19. Across the 7,247 U.S. stations with normals, its annual mean of 43.5°F is warmer than 14%.
In the Köppen classification computed from these normals, Diversion Dam is BSk: cold semi-arid steppe. 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 Diversion Dam share this climate record?
Fort Washakie 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.
- Fort Washakie, WY1,345 people · 16 mi S
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 Diversion Dam's climate
What is the coldest month at Diversion Dam?
December, with a normal high of 34°F and a normal low of 8°F. The warmest is July (85°F by day, 51°F at night).
Does it snow at Diversion Dam?
Yes: 29 inches in a normal year, falling on 15 days with 0.1 inch or more, the most in April (5.1 inches).
What is the rainiest month at Diversion Dam?
May, with 2.27 in of precipitation in a normal year; the driest is January with 0.16 in.
What plant hardiness zone is Diversion Dam in?
The USDA's 2023 map puts Diversion Dam in zone 5a in ZIP code 82516, the nearest ZIP area.
How late can frost come at Diversion Dam?
In half of years the last 32°F night comes after May 21; in one year in ten it comes after June 6. Waiting until June 6 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Wyoming climateThe statewide normals and every place in the state
- Pavillion, WY11 miles from this station, 45.0°F a year
- Burris, WY21 miles from this station, 42.9°F a year
- Riverton, WY25 miles from this station, 44.5°F a year
- Lander, WY30 miles from this station, 45.1°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made