Kick off the 25th anniversary season of Colorado's premier summer swim-run series at the Boulder Stroke & Stride on Thursday, June 4, 2026. This legendary weekly event is where Boulder's vibrant triathlon community gathers at the scenic Boulder Reservoir, offering a thrilling open-water swim of 750 or 1500 meters followed by a fast 5k run on the reservoir dam. The series opener is the perfect place to make your open-water debut in the friendly 750m event or challenge yourself alongside elite athletes in the competitive 1500m wave. Dive in at 6:00 PM after a free clinic by D3 Multisport coaches, perfecting your technique before the start gun fires. As a special pre-registration-only event with limited space for the first two weeks, securing your spot early is essential to join 250-400 fellow athletes for this iconic summer tradition.
Beyond the race, enjoy the fantastic post-race atmosphere with great food, live timing, and the camaraderie that has defined this event for a quarter-century. Whether you're testing the waters for the first time, sharpening your speed week after week, or opting for a six-pack entry to guarantee your spot all season, the Stroke & Stride delivers pure, uncomplicated multisport fun. Mark your calendar for June 4th, feel the unique energy of the season opener, and start your summer of Thursday night racing under the Colorado sky.
Races Offered
1 Mile - Swim ONLY
Jun 04, 2026
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Distance —
1.6K
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Type —
Water sports
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14 days remaining
1/2 Mile - Swim ONLY
Jun 04, 2026
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Distance —
0.8K
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Type —
Water sports
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14 days remaining
5k - Run ONLY
Jun 04, 2026
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Distance —
5K
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Type —
Water sports
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14 days remaining
Long Course - Swim & Run
Jun 04, 2026
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Distance —
6.6K
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Type —
Water sports
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14 days remaining
Short Course - Swim & Run
Jun 04, 2026
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Distance —
5.8K
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Type —
Water sports
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14 days remaining
Weather History
These values represent the 3-year monthly averages for June in Boulder.
thermostatTemperature
11.8° / 25.9°
wb_sunnyFeels like
9.8° / 24.1°
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Avg sunshine hours
12h 23m
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Avg rainfall
1.8 mm
ac_unit
Avg snowfall
—
air
Avg wind speed
7.4 km/h (Light breeze)
opacity
Sweat loss rate
Moderate
terrain
Course conditions
Firm and slightly soft
sunny
Max UV Index
Very High (8.0)
humidity_mid
Humidity
55.1%
wb_twilight
Sunrise
05:32
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Sunset
20:30
About Boulder
Learn more about the host city, Boulder.
Boulder is a college town of about 106,000 in the Front Range region of Colorado. The home of the University of Colorado, the city has a reputation for progressive values and outdoor recreation. It is a very pleasant place to live and visit.
