Daylight through the yearLongest day (Jun 21): 15 h 1 min5:32 am – 8:33 pmShortest day (Dec 21): 9 h 20 min7:19 am – 4:39 pm
Sun todaySunrise –Sunset –
Natural hazardsOverall risk Relatively ModerateBoulder County, CO, compared with all US countiesHigher-risk hazardsLightning Very HighHail Relatively HighWildfire Relatively HighWinter weather Relatively HighSource: FEMA National Risk Index (county level)
Air quality58% of days had good air in 2025213 of 365 days measured149 moderate, 3 unhealthy for sensitive groups daysMedian index 48, worst day 119main pollutant: ozoneSource: US EPA Air Quality Index, Boulder County monitors, CO
Drinking waterCity of Boulderserves 166,080 people from surface waterNo health-based violations since 20212 monitoring or reporting violations since 2021Source: US EPA Safe Drinking Water Information System, largest system serving the town
