Jamestown, CO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Jamestown, a town in Boulder County, Colorado.
Today
67°F
Patchy Smoke
Patchy smoke and a slight chance of rain showers before noon, then patchy smoke and a slight chance of showers and thunderstorms. Mostly sunny. High near 67, with temperatures falling to around 65 in the afternoon. East southeast wind 3 to 8 mph. Chance of precipitation is 20%.
7-day forecast for Jamestown
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 67°F | Patchy Smoke | 3 to 8 mph ESE | 18% |
| Tonight | 51°F | Patchy Smoke | 2 to 7 mph NNW | 13% |
| Wednesday | 75°F | Sunny | 3 to 7 mph NE | 3% |
| Wednesday Night | 52°F | Mostly Clear | 2 to 6 mph SW | 1% |
| Thursday | 83°F | Sunny | 2 to 6 mph N | 2% |
| Thursday Night | 57°F | Mostly Clear | 6 mph NNW | 1% |
| Friday | 85°F | Sunny | 3 to 7 mph NNE | 0% |
| Friday Night | 60°F | Mostly Clear | 3 to 8 mph WNW | 0% |
| Saturday | 87°F | Sunny | 3 to 8 mph NNW | 6% |
| Saturday Night | 63°F | Partly Cloudy | 6 mph W | 2% |
| Sunday | 86°F | Sunny | 5 mph N | 10% |
| Sunday Night | 64°F | Partly Cloudy | 3 to 7 mph WNW | 8% |
| Monday | 85°F | Slight Chance Rain Showers then Chance Showers And Thunderstorms | 7 mph ENE | 42% |
| Monday Night | 61°F | Slight Chance Showers And Thunderstorms then Mostly Cloudy | 6 mph WSW | 23% |
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 Aug 4, 2026.