Newcastle, Wyoming climate: Normal weather by month, frost dates and records
Newcastle's normal year runs from 14°F January nights to 87°F July afternoons, with 17.2 inches of precipitation and 39 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.5°C, January lows of −10°C, July highs of 30°C, 436 mm of precipitation a year.
- NOAA stationNewcastle
- Station IDUSC00486660
- Location43.85°N 104.19°W
- Elevation4,415 ft (1,346 m)
- Population3,354
On October 23, the normal high in Newcastle is 55°F and the normal low 33°F, and the chance of measurable rain or snow is 20%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Newcastle.
- Jan 35° 14°
- Feb 38° 16°
- Mar 48° 26°
- Apr 57° 33°
- May 66° 43°
- Jun 78° 53°
- Jul 87° 60°
- Aug 86° 59°
- Sep 75° 49°
- Oct 59° 36°
- Nov 45° 24°
- Dec 35° 15°
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 Newcastle each month?
July is the warmest month, with normal highs of 87°F; January the coldest, with normal lows of 14°F. The most precipitation falls in May (2.90 in), the least in January (0.51 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 35°F | 14°F | 24.4°F | 0.51 | 6.8 | 6 | <1 | 31 | 9 h 10 min |
| February | 38°F | 16°F | 26.9°F | 0.67 | 7.7 | 6 | <1 | 27 | 10 h 30 min |
| March | 48°F | 26°F | 36.9°F | 0.77 | 4.9 | 6 | <1 | 24 | 11 h 50 min |
| April | 57°F | 33°F | 45.2°F | 1.70 | 5.0 | 8 | <1 | 15 | 13 h 20 min |
| May | 66°F | 43°F | 54.8°F | 2.90 | 0.6 | 11 | 1 | 4 | 14 h 40 min |
| June | 78°F | 53°F | 65.3°F | 2.68 | 0.0 | 11 | 4 | <1 | 15 h 30 min |
| July | 87°F | 60°F | 73.4°F | 2.54 | 0.0 | 9 | 14 | <1 | 15 h 10 min |
| August | 86°F | 59°F | 72.1°F | 1.82 | 0.0 | 7 | 13 | <1 | 14 h |
| September | 75°F | 49°F | 62.0°F | 1.20 | 0.2 | 6 | 4 | 1 | 12 h 40 min |
| October | 59°F | 36°F | 47.2°F | 1.24 | 1.4 | 7 | <1 | 11 | 11 h 10 min |
| November | 45°F | 24°F | 34.6°F | 0.59 | 5.5 | 5 | <1 | 25 | 9 h 40 min |
| December | 35°F | 15°F | 24.8°F | 0.54 | 6.8 | 6 | <1 | 31 | 9 h |
| Year (annual) | 59°F | 36°F | 47.3°F | 17.16 | 38.9 | 88 | 34 | 168 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 1°C | −10°C | −4.2°C | 13 mm | 17 cm |
| February | 3°C | −9°C | −2.8°C | 17 mm | 20 cm |
| March | 9°C | −4°C | 2.7°C | 20 mm | 12 cm |
| April | 14°C | 1°C | 7.3°C | 43 mm | 13 cm |
| May | 19°C | 6°C | 12.7°C | 74 mm | 2 cm |
| June | 25°C | 12°C | 18.5°C | 68 mm | 0 cm |
| July | 30°C | 16°C | 23.0°C | 65 mm | 0 cm |
| August | 30°C | 15°C | 22.3°C | 46 mm | 0 cm |
| September | 24°C | 9°C | 16.7°C | 30 mm | 1 cm |
| October | 15°C | 2°C | 8.4°C | 31 mm | 4 cm |
| November | 7°C | −4°C | 1.4°C | 15 mm | 14 cm |
| December | 1°C | −9°C | −4.0°C | 14 mm | 17 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00486660; 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 Newcastle?
Normal highs sit between 65°F and 85°F in May, June 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 USC00486660.
When is the last frost in Newcastle?
In Newcastle, 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 October 3 in half of years and before September 17 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 April 30
- First autumn frost, half of years before
- October 31 year in 10 before September 17; 9 in 10 before October 16
NOAA puts the median frost-free season at 143 days, and the season without a hard freeze (28°F) at 162 days.
A hard freeze (28°F) comes after May 1 in half of springs and before October 11 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Newcastle in zone 4b in ZIP code 82723, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, Newcastle's NOAA station is in zone 5a: the coldest night of a typical year reaches −17°F (26 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 Wyoming · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00486660; 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 Newcastle?
In a normal year in Newcastle, 34 days a year reach 90°F (3 of them 100°F or more), 168 nights fall to 32°F or colder and 88 days bring measurable precipitation.
- Days at 90°F or more
- 34a normal year
- Days at 100°F or more
- 3a normal year
- Nights at 32°F or colder
- 168a normal year
- Days that stay below freezing
- 40high of 32°F or less
- Days with 0.01 inch of precipitation
- 88a normal year
- Days with 1 inch of snow or more
- 17a normal year
The highest temperature in this station's record (since 1906) is 108°F, on July 5, 1936; the lowest is −37°F, on January 17, 1930.
The wettest calendar year on that record is 1996, with 24.34 in; the snowiest season is 1993–94, with 69.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00486660; records: ACIS (NOAA Regional Climate Centers), station USC00486660. Records use complete months only; a month missing more than three days is left out.
How sunny is Newcastle?
Over a year 79% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Newcastle, 4.4 kWh per square metre a day. July is the sunniest month (88%) and December the cloudiest (71%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 74% | 2.0 |
| February | 73% | 2.9 |
| March | 73% | 4.1 |
| April | 73% | 5.2 |
| May | 75% | 6.2 |
| June | 83% | 7.2 |
| July | 88% | 7.3 |
| August | 87% | 6.3 |
| September | 84% | 4.9 |
| October | 76% | 3.3 |
| 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 much heating and cooling does Newcastle need?
A normal year in Newcastle brings 7,130 heating degree days, 33% more than the median U.S. place (5,373), and 711 cooling degree days, 22% 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 2,641 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,259 | 0 |
| February | 1,067 | 0 |
| March | 871 | 0 |
| April | 597 | 1 |
| May | 334 | 18 |
| June | 92 | 101 |
| July | 13 | 273 |
| August | 23 | 241 |
| September | 163 | 75 |
| October | 555 | 3 |
| November | 912 | 0 |
| December | 1,246 | 0 |
| Year (annual) | 7,130 | 711 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00486660. 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 Newcastle been warmer than normal lately?
2025 averaged 48.0°F, 0.7°F above the 1991-2020 normal of 47.3°F. 2 of the 3 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 48.4°F | +1.1°F | – | – |
| 2022 | 46.7°F | −0.6°F | – | 27.4 |
| 2025 | 48.0°F | +0.7°F | – | – |
Over 84 complete years from 1910 to 2025, the station's annual mean temperature rose at a fitted 0.7°F per century (+0.04°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USC00486660; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Newcastle's climate compare?
Newcastle is warmer than 60 of the other 70 places with their own NOAA record in Wyoming, and wetter than 51. Across the 7,247 U.S. stations with normals, its annual mean of 47.3°F is warmer than 29%.
In the Köppen classification computed from these normals, Newcastle 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 Newcastle share this climate record?
Hill View Heights 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.
- Hill View Heights, WY249 people · 3 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 Newcastle's climate
What is the coldest month in Newcastle?
January, with a normal high of 35°F and a normal low of 14°F. The warmest is July (87°F by day, 60°F at night).
Does it snow in Newcastle?
Yes: 39 inches in a normal year, falling on 20 days with 0.1 inch or more, the most in February (7.7 inches).
What is the rainiest month in Newcastle?
May, with 2.90 in of precipitation in a normal year; the driest is January with 0.51 in.
What plant hardiness zone is Newcastle in?
The USDA's 2023 map puts Newcastle in zone 4b in ZIP code 82723, the nearest ZIP area. By the same method at Newcastle's NOAA station, the coldest night of a typical year reaches −17°F (26 years, 1991-2020): zone 5a.
How late can frost come in Newcastle?
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
- Wyoming climateThe statewide normals and every place in the state
- Upton, WY27 miles from this station, 44.8°F a year
- Rochford (2 mi WNW), SD29 miles from this station, 38.8°F a year
- Custer, SD30 miles from this station, 43.1°F a year
- Hill City, SD32 miles from this station, 43.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made