Louisville Weather -- Boulder County, CO

Louisville, CO -- US-36 Corridor City in Boulder County

Louisville sits in the plains-foothills transition zone of southeastern Boulder County, about ten miles east of the Flatirons and roughly halfway between Boulder and the metro Denver edge. At an average elevation of 5,337 feet, Louisville has a climate that blends plains warmth with foothills wind exposure -- summers run a few degrees warmer than higher-elevation Boulder neighborhoods, snowfall totals are roughly 20–30 percent lower than the foothills, and Chinook and downslope wind events arrive with little terrain to slow them.

The city's western edge meets Marshall Mesa Open Space and the broader wildland-urban interface that defines this part of Boulder County. That interface, combined with the same downslope wind pattern that shapes daily weather, has produced the defining recent weather event in Louisville's history: the December 30, 2021 Marshall Fire. Driven by 100+ mph downslope winds across dry grassland, the fire moved east through Marshall and into Louisville and Superior in less than an afternoon, destroying hundreds of homes and forever changing how Louisville residents think about wildfire risk on the plains.

Fire Risk and History

Louisville carries a high wildfire risk despite its plains-adjacent location. The Marshall Fire (December 30, 2021) destroyed approximately 550 homes within Louisville city limits and burned 6,026 acres across the broader area in a single afternoon. The fire originated near Marshall, west of Louisville, and was driven east by sustained winds gusting over 100 mph through dry winter grassland. It remains the most destructive wildfire in Colorado history by structure count.

The conditions that drove the Marshall Fire -- extreme downslope wind events, dry winter grassland, and a wildland-urban interface running directly along the city's western edge -- recur every season. Louisville's Wildfire Mitigation Program provides defensible-space guidelines specifically designed for this plains-foothills risk profile. Residents in the western neighborhoods near Marshall Mesa face the highest exposure.

Elevation and Microclimate

At 5,337 feet, Louisville sits roughly 100 feet lower than central Boulder and several hundred feet below the foothills neighborhoods west of US-36. The flat plains terrain east of Marshall Mesa offers little wind protection, and the city is regularly affected by the same Bora and Chinook downslope wind events that shape Boulder's foothills weather -- often with stronger sustained winds because there are no terrain obstructions to slow them. UV exposure at this elevation runs about 20 percent stronger than sea level. Summer highs average a few degrees warmer than central Boulder, and winter snowfall totals are typically the lightest in the corridor.

Flood Zone Information

Louisville is largely classified FEMA Flood Zone X with minimal flood risk for the residential areas of the city. Coal Creek runs through Louisville and produced notable flows during the September 2013 regional flood event, with localized impacts along the creek corridor. Properties immediately adjacent to Coal Creek and its tributaries should verify their specific parcel designation at FEMA's Flood Map Service Center. The 2013 flood damaged some Coal Creek bridge crossings and trail infrastructure but did not produce the residential destruction seen in upstream St Vrain communities like Lyons or Jamestown.

Nearby Weather Pages

• Superior weather -- adjacent city, also affected by Marshall Fire
• Lafayette weather -- next city east on SH-7
• Erie weather -- plains community further east