New Castle, CO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for New Castle, a town in Garfield County, Colorado.
Tonight
32°F
Partly Cloudy
Partly cloudy, with a low around 32. East wind around 5 mph.
7-day forecast for New Castle
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 32°F | Partly Cloudy | 5 mph E | 1% |
| Wednesday | 54°F | Showers And Thunderstorms Likely | 5 to 10 mph WNW | 62% |
| Wednesday Night | 32°F | Chance Rain And Snow Showers then Mostly Cloudy | 0 to 5 mph SW | 62% |
| Thursday | 57°F | Sunny | 0 to 5 mph S | 0% |
| Thursday Night | 33°F | Partly Cloudy | 0 mph | 5% |
| Friday | 57°F | Mostly Sunny | 0 to 5 mph WSW | 5% |
| Friday Night | 30°F | Mostly Clear | 0 mph | 4% |
| Saturday | 59°F | Sunny | 0 to 5 mph S | 0% |
| Saturday Night | 32°F | Clear | 0 to 5 mph ENE | 0% |
| Sunday | 63°F | Sunny | 0 to 5 mph SW | 0% |
| Sunday Night | 35°F | Mostly Clear | 0 mph | 0% |
| Monday | 64°F | Mostly Sunny | 0 to 5 mph SSW | 1% |
| Monday Night | 37°F | Partly Cloudy | 0 mph | 3% |
| Tuesday | 64°F | Mostly Sunny | 0 to 5 mph SSW | 9% |
Forecast source: National Weather Service (api.weather.gov) for New Castle (39.578, -107.526). Updated through the day.
Growing snapshot for New Castle
Last spring frost
May 23
First fall frost
Sep 25
Growing season
124 days
Hardiness zone
6a
More local growing data for New Castle: nearby ZIP 81647 weather · frost dates · planting calendar · Colorado frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Rifle 3Ene, Co (10.4 mi from New Castle). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.