Hygiene Weather -- Boulder County, CO

Hygiene, CO -- Left Hand Creek CDP, Boulder County

Hygiene is a small census-designated place in northwestern Boulder County, located in the agricultural corridor between Longmont and Lyons at 5,069 feet. The community occupies gently rolling terrain in the Left Hand Creek drainage, roughly four miles northwest of downtown Longmont and eight miles southeast of Lyons at the canyon mouth. Crop fields, horse properties, and rural residential development characterize the unincorporated landscape around Hygiene — a community that has remained outside city limits and retains a working agricultural character uncommon this close to the Boulder-Denver metro edge.

Hygiene's position between the canyon mouth at Lyons and the plains city of Longmont places it in a meaningful wind corridor. Down-canyon flows from St Vrain Canyon to the northwest arrive with less buffering than in Longmont proper, producing locally stronger wind events during Chinook and downslope episodes. The community is also exposed to northeast and north winds pushing across open plains from the Larimer County line. At 5,069 feet, temperatures sit slightly cooler than central Longmont but warmer than foothills communities above 5,500 feet — a mild elevation band that extends the growing season compared to the mountain towns to the west.

Left Hand Creek crosses near Hygiene as it flows east from the mountains toward Longmont and the St Vrain confluence. In September 2013, Left Hand Creek experienced the most destructive flows in its recorded history during the regional Front Range flood: roads were washed out, bridges destroyed, and agricultural land along the creek corridor was inundated for miles. Hygiene Road and several connecting county roads required significant post-flood reconstruction, and the Left Hand drainage through this area has been subject to flood mitigation study since.

Fire Risk and History

Hygiene carries a low wildfire risk for its plains and lower-foothills setting, though the western edge of the community approaches the foothills WUI corridor that extends south from Lyons toward Left Hand Canyon. The Cold Springs Fire (2016) burned 528 acres near Nederland, approximately 15 miles to the west, illustrating the fire environment in the canyon terrain above Hygiene. The Colorado State Forest Service wildfire risk mapping shows primary wildfire exposure concentrated at the foothills interface rather than in the agricultural plains that make up most of Hygiene's area.

Elevation and Microclimate

At 5,069 feet, Hygiene sits at nearly the same elevation as Niwot to the south and roughly 300 feet below Lyons to the northwest. UV exposure is approximately 20 percent above sea level. Annual snowfall averages in the 50–60 inch range typical of north Boulder County plains communities, with the highest single-storm totals arriving from upslope northeast flow patterns. Cold air drainage from the foothills can produce sharp overnight temperature drops in Hygiene's lower-lying agricultural corridors — a meaningful consideration for frost-sensitive crops and early-season planting.

Flood Zone Information

Hygiene is largely FEMA Flood Zone X with minimal flood risk for most of the community, with AE flood hazard designations along the Left Hand Creek corridor. The September 2013 flood caused significant road and infrastructure damage through the Hygiene area, and post-flood bridge and road reconstruction has reshaped several routes through the community. Specific parcel flood status should be verified at FEMA's Flood Map Service Center.

Nearby Weather Pages

• Longmont weather -- city to the southeast
• Lyons weather -- canyon-mouth town to the northwest
• Niwot weather -- plains CDP to the south