Boulder, Colorado Weather:
Sunday, September 20, 2026
Sunny with a Chance of Thunderstorms
Day 72°
Night 46°
Precipitation 55 %
Wind 6 mph
UV Index (0 - 11+) 5
Weather Forecast History
Last Year's Weather on This Day (September 20, 2025)
Stormy Weather

Day

82°

Night

57°

Wind

6 mph

Precipitation

55 %