Jamestown, CO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Jamestown, a town in Boulder County, Colorado.
This Afternoon
48°F
Sunny
Sunny. High near 48, with temperatures falling to around 39 in the afternoon. East southeast wind around 2 mph.
7-day forecast for Jamestown
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 48°F | Sunny | 2 mph ESE | 1% |
| Tonight | 32°F | Mostly Clear | 3 mph SW | 1% |
| Wednesday | 47°F | Partly Sunny then Slight Chance Rain And Snow Showers | 1 to 6 mph NE | 17% |
| Wednesday Night | 31°F | Slight Chance Rain And Snow Showers then Mostly Cloudy | 3 mph NW | 18% |
| Thursday | 53°F | Sunny | 1 to 7 mph SSE | 0% |
| Thursday Night | 34°F | Partly Cloudy | 3 mph WSW | 1% |
| Friday | 51°F | Mostly Sunny then Slight Chance Rain And Snow Showers | 1 to 5 mph SSE | 16% |
| Friday Night | 32°F | Slight Chance Rain And Snow Showers then Partly Cloudy | 2 to 8 mph W | 16% |
| Saturday | 54°F | Sunny | 0 to 10 mph NNE | 2% |
| Saturday Night | 33°F | Mostly Clear | 1 to 7 mph W | 1% |
| Sunday | 61°F | Sunny | 0 to 10 mph W | 0% |
| Sunday Night | 41°F | Mostly Clear | 6 to 10 mph W | 0% |
| Monday | 60°F | Mostly Sunny | 1 to 12 mph NW | 0% |
| Monday Night | 39°F | Partly Cloudy | 1 to 7 mph W | 0% |
Forecast source: National Weather Service (api.weather.gov) for Jamestown (40.123, -105.393). Updated through the day.
Growing snapshot for Jamestown
Last spring frost
Jun 21
First fall frost
Sep 2
Growing season
71 days
Hardiness zone
5b
More local growing data for Jamestown: nearby ZIP 80455 weather · frost dates · planting calendar · Colorado frost dates
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Climate data from the nearest NOAA station, Boulder 14 W, Co (8.6 mi from Jamestown). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.