New Castle, CO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for New Castle, a town in Garfield County, Colorado.
Today
97°F
Patchy Smoke
Patchy smoke. Sunny, with a high near 97. South wind 5 to 15 mph, with gusts as high as 30 mph.
7-day forecast for New Castle
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 97°F | Patchy Smoke | 5 to 15 mph S | 1% |
| Tonight | 56°F | Patchy Smoke then Mostly Clear | 0 to 15 mph N | 1% |
| Wednesday | 95°F | Sunny | 0 to 15 mph WSW | 0% |
| Wednesday Night | 54°F | Mostly Clear | 5 to 15 mph N | 0% |
| Thursday | 96°F | Sunny | 5 to 10 mph SW | 0% |
| Thursday Night | 56°F | Clear | 5 to 10 mph NNE | 0% |
| Friday | 98°F | Sunny | 5 to 10 mph S | 0% |
| Friday Night | 58°F | Mostly Clear | 5 to 10 mph NNE | 0% |
| Saturday | 99°F | Sunny | 5 to 10 mph SSW | 0% |
| Saturday Night | 60°F | Mostly Clear | 5 to 10 mph NNE | 0% |
| Sunday | 98°F | Sunny | 5 to 10 mph SSW | 1% |
| Sunday Night | 62°F | Partly Cloudy | 5 to 10 mph NNE | 5% |
| Monday | 96°F | Sunny then Slight Chance Showers And Thunderstorms | 5 to 10 mph SW | 15% |
| Monday Night | 60°F | Chance Showers And Thunderstorms then Mostly Cloudy | 0 to 10 mph NE | 25% |
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 Aug 4, 2026.