Today marks the official start of astronomical summer in the Northern Hemisphere. The summer solstice, which falls on June 20 or 21 each year, brings the longest day of the year and the highest sun angle before daylight slowly begins to decrease again.
While many people picture the first day of summer as hot, sunny, and dry, Denver’s climate history tells a much more interesting story.
A Look Back: Denver’s Summer Solstice Climate
Denver’s weather records dating back to 1872 show that there is no such thing as a “typical” first day of summer in Colorado.
On average, the summer solstice brings:
- High temperature: 83.6°F
- Low temperature: 55.0°F
- Average daily temperature: 69.3°F
- Precipitation: 0.02 inches
The median precipitation is actually 0.00 inches, meaning most years are dry. However, Colorado’s weather extremes shine through in the historical record.
Summer Solstice Extremes in Denver
- Warmest high: 99°F (2007 and 2017)
- Coolest high: 60°F (1947)
- Warmest low: 69°F (1922)
- Coolest low: 40°F (1947)
- Wettest summer solstice: 1.85 inches of rain (2023)
Perhaps the most striking statistic is the range in temperatures. Denver has seen first days of summer that felt more like mid-April, while others have delivered full-blown July heat.
In fact, the difference between the warmest and coolest summer solstice highs is nearly 40 degrees.
Colorado’s Early Summer Personality
Late June often represents a seasonal transition across Colorado.
Spring storm systems become less frequent, but they haven’t disappeared entirely. Meanwhile, increasing heat and strengthening sunshine begin fueling more regular afternoon thunderstorms, especially over the mountains and eastern plains.
The result is one of Colorado’s most dynamic periods of the year.
It’s not unusual to experience sunshine during the morning, gusty winds by afternoon, and thunderstorms before sunset. The atmosphere is often balancing between lingering spring influences and the building heat of summer.
How Did This Year’s Solstice Compare?
The first day of summer in 2026 was a reminder that Colorado rarely follows a script.
Rather than widespread heat or a perfectly clear sky, the region remained under an active weather pattern. Severe thunderstorms developed across portions of the eastern plains, wildfire smoke drifting from Utah occasionally produced hazy skies, and elevated fire weather concerns persisted in the high country.
Yet, in many ways, these conditions fit Colorado’s summer climatology remarkably well.
June is one of Denver’s wetter months, severe thunderstorms become increasingly common east of the Front Range, and wildfire smoke has unfortunately become a more familiar part of the warm season in recent years.
The Bottom Line
If Denver’s 150 years of climate records teach us anything, it’s that there is no single definition of what the first day of summer should feel like.
It might be 60 degrees with soaking rain. It might be pushing 100 degrees under cloudless skies. It could bring severe thunderstorms, smoky sunsets, or a picture-perfect evening on the patio.
This year, the summer solstice delivered a little bit of Colorado’s signature unpredictability.
And perhaps that’s the most typical thing of all.