Weather Alerts For Denver International Airport, CO

# HEADLINE -------------------- RED FLAG WARNING IN EFFECT FROM 10 AM WEDNESDAY TO MIDNIGHT MDT WEDNESDAY NIGHT FOR WIND AND LOW RELATIVE HUMIDITY FOR THE FRONT RANGE FOOTHILLS, URBAN CORRIDOR, PLAINS, AND SOUTH PARK # SUMMARY -------------------- The National Weather Service in Denver has issued a Red Flag Warning for wind and low relative humidity, which is in effect from 10 AM Wednesday to midnight MDT Wednesday night. The Fire Weather Watch is no longer in effect. # DETAILS -------------------- AFFECTED AREA Fire Weather Zones 214, 216, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250 and 251. TIMING From 10 AM Wednesday to midnight MDT Wednesday night. WINDS Southwest 15 to 30 mph with gusts up to 45 mph. RELATIVE HUMIDITY 4 to 9 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. ISSUED AT Monday, April 20, 2026 at 8:48 PM MDT ISSUED BY National Weather Service Denver/Boulder CO HEADER URGENT - FIRE WEATHER MESSAGE # PRECAUTIONARY/PREPAREDNESS ACTIONS -------------------- A Red Flag Warning means that critical fire weather conditions are either occurring now....or will shortly. A combination of strong winds...low relative humidity...and warm temperatures can contribute to extreme fire behavior. # AREAS AFFECTED -------------------- Boulder And Jefferson Counties Below 6000 Feet/West Broomfield County, Central and East Adams and Arapahoe Counties, Elbert/Central and East Douglas Counties Above 6000 Feet, Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear Creek/Northeast Park Counties Below 9000 Feet, Larimer County Below 6000 Feet/Northwest Weld County, Logan County, North and Northeast Elbert County Below 6000 Feet/North Lincoln County, North Douglas County Below 6000 Feet/Denver/West Adams and Arapahoe Counties/East Broomfield County, Northeast Weld County, Southeast Elbert County Below 6000 Feet/South Lincoln County, Central and South Weld County, Central and Southeast Park County, Morgan County, Phillips County, Sedgwick County, Washington County

# HEADLINE -------------------- OZONE ACTION DAY ALERT FROM 400 PM MONDAY UNTIL 1200 AM TUESDAY # SUMMARY -------------------- The Colorado Department of Public Health and Environment has issued the following... WHAT...Ozone Action Day Alert. # DETAILS -------------------- WHERE Douglas, Jefferson, Denver, western Arapahoe, western Adams, Broomfield, Boulder, Larimer, and Weld Counties WHEN 400 PM Monday April 20 to 1200 AM Tuesday April 21 IMPACTS Ozone Action Day Alert is now in effect for the Front Range Urban Corridor. An intrusion of ozone from high in the atmosphere could raise ozone levels into the Unhealthy for Sensitive Groups category Monday afternoon and evening. Lower ozone levels are expected on Tuesday. For Colorado air quality conditions, forecasts, and advisories, visit: https://www.colorado.gov/airquality/colorado\_summary.aspx If possible, please help us reduce pollution by limiting driving gas and diesel-powered vehicles until at least 4 PM Tuesday, April 21, 2026. Colorado is also addressing ozone pollution through state policies. For more information about health impacts and how ozone pollution forms in Colorado, visit: https://cdphe.colorado.gov/ozone-pollution- and-your-health HEALTH INFORMATION Increasing likelihood of respiratory symptoms and breathing discomfort in active children and adults and people with lung disease, such as asthma. Active children and adults, and people with lung disease, such as asthma, should reduce prolonged or heavy outdoor exertion. ISSUED AT Monday, April 20, 2026 at 4:10 PM MDT ISSUED BY Relayed by National Weather Service Boulder CO HEADER Air Quality Alert Message | Colorado Department of Public Health and Environment # AREAS AFFECTED -------------------- Jefferson, Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Larimer, Weld

Pollen Index: 11.6 Pollen Level: high Predominant Pollen: Elm, Oak and Maple. The quantity of pollen grains in the air for Tuesday will remain relatively stable in the extremely high range. No change doesn't mean no pollen, it just means that pollen producing plants are delivering pollen at a steady pace.