Fire Weather Watch

Locations Affected

Denver, CO ∙ Aurora, CO ∙ Fort Collins, CO ∙ Lakewood, CO ∙ Westminster, CO ∙ Boulder, CO ∙ Arvada, CO ∙ Thornton, CO ∙ Centennial, CO ∙ Longmont, CO

Headline

...CRITICAL FIRE WEATHER CONDITIONS THURSDAY AND FRIDAY...
Strong northwest winds will spread across the northeast plains after sunrise today, with gusts 45 to 65 mph creating critical fire weather conditions despite somewhat marginal humidity values near 20%.
Early Friday, westerly downslope winds will bring strong gusts to the Front Range mountains and foothills, with potential for these to spread into wind-favored portions of the adjacent lower elevations. Peak gusts of 70-90 mph are increasing in likelihood for the windiest locations (considerably lower for areas along and east of I-25). With a warmer and drier air mass in place, humidity values in the teens look to extend into much of the foothills, and certainly across the lower elevations. Such conditions may be a longer duration than usual, with potential for low humidity to extend into the evening hours prior to the arrival of a front.

Full Alert Message

URGENT - FIRE WEATHER MESSAGE National Weather Service Denver/Boulder CO 231 AM MST Thu Dec 18 2025 ...CRITICAL FIRE WEATHER CONDITIONS THURSDAY AND FRIDAY... Strong northwest winds will spread across the northeast plains after sunrise today, with gusts 45 to 65 mph creating critical fire weather conditions despite somewhat marginal humidity values near 20%. Early Friday, westerly downslope winds will bring strong gusts to the Front Range mountains and foothills, with potential for these to spread into wind-favored portions of the adjacent lower elevations. Peak gusts of 70-90 mph are increasing in likelihood for the windiest locations (considerably lower for areas along and east of I-25). With a warmer and drier air mass in place, humidity values in the teens look to extend into much of the foothills, and certainly across the lower elevations. Such conditions may be a longer duration than usual, with potential for low humidity to extend into the evening hours prior to the arrival of a front. ...FIRE WEATHER WATCH NOW IN EFFECT FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR WIND AND LOW RELATIVE HUMIDITY... * AFFECTED AREA...Fire Weather Zones 238, 239 and 240. * TIMING...From Friday morning through Friday evening. * WINDS...West 25 to 35 mph with gusts 70 to 80 mph near the base of the foothills. West 15 to 25 mph with gusts up to 45 mph closer to the I-25 corridor. * RELATIVE HUMIDITY...As low as 10 percent. * IMPACTS...Conditions will be favorable for rapid fire spread. Avoid outdoor burning and any activity that may produce a spark and start a wildfire. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Fire Weather Watch means that critical fire weather conditions are forecast to occur. Listen for later forecasts and possible Red Flag Warnings.

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