Jamestown Weather -- Boulder County, CO

Jamestown, CO -- James Creek Canyon Town in Boulder County

At roughly 2 a.m. on September 12, 2013, Jamestown residents were woken and told to get to higher ground as James Creek and Little James Creek tore through the canyon -- an event that killed one longtime resident, destroyed eighteen homes and the fire station, and left the town an island between two washed-out road sections until the Colorado National Guard airlifted people out. Jamestown sits at about 6,920 feet at the confluence of James Creek and Little James Creek in the upper Lefthand Creek drainage, on the single canyon road that is its only way in or out.

That canyon geography shapes the daily weather as much as the disasters. Steep walls funnel and accelerate down-canyon winds, and the narrow valley channels both the cold air that drains off the high country at night and the runoff that pours through after any heavy rain. Sitting some 1,600 feet above the Boulder plains, Jamestown runs cooler and noticeably snowier than the city, with snow lingering in the shaded canyon bottom long after it has melted below.

The same steep, timbered terrain that makes the canyon flood-prone also makes it burn. Post-fire rainstorms have repeatedly pushed water and debris down the drainage into town, tying Jamestown's fire and flood risks together into a single hazard.

Fire Risk and History

Jamestown carries an extreme wildfire risk driven by dense canyon timber and steep, wind-aligned terrain. The CalWood Fire ignited October 17, 2020 near the Cal-Wood Education Center just north of town, exploded past 7,000 acres on its first day, reached roughly 10,000 acres, and forced Jamestown's evacuation -- the largest wildfire in Boulder County's recorded history at the time. The earlier Overland Fire burned in the same drainage, and its scar later channeled debris flows toward the community. A grassroots wildfire-mitigation effort has since treated dozens of private properties around Jamestown to protect both the town and the watershed downstream; residents can also use Boulder County's Wildfire Partners program.

Elevation and Microclimate

At about 6,920 feet, Jamestown occupies the foothills canyon band -- high enough for meaningful snowpack and strong UV, low enough to escape the deep subalpine cold of the Peak to Peak towns above it. The canyon's orientation governs its microclimate: morning shade lingers on the north wall, afternoon downslope gusts rake the valley, and overnight cold-air drainage from James Canyon can leave the creek bottom several degrees colder than the surrounding slopes.

Flood Zone Information

Jamestown is a FEMA Flood Zone AE community along James Creek, with a mapped regulated floodway through the heart of town. The September 2013 flood far exceeded the then-mapped 100-year levels and destroyed homes that were outside the old floodplain, prompting a full remap of the drainage through the Colorado Hazard Mapping Program. Verify any parcel's current designation at FEMA's Flood Map Service Center. Intense summer thunderstorms over burn scars are the most dangerous flood trigger here.

Nearby Weather Pages

• Ward weather -- highest town in the county, up the Lefthand drainage
• Lyons weather -- St Vrain canyon town also hit hard in 2013
• Allenspark weather -- mountain community near RMNP's Wild Basin