Entry No. 68 — the Boulder file — filed under: after-dark
OSMP Full Moon Night Hikes
The City of Boulder's Open Space and Mountain Parks and Boulder County both run rotating series of naturalist-led night hikes that take small groups into preserves which normally close at sunset. OSMP's "Welcome the Night" full-moon hikes climb toward a Flagstaff overlook timed to catch the sun dropping over the Continental Divide on one side and the full moon rising over the plains on the other; Boulder County's volunteer naturalists lead moonlight walks that explore how wildlife adapts to the dark. Groups are capped small (often around 15) and registration is required. The programs themselves are free, though a few trailheads charge a small parking fee for out-of-county vehicles.
The story
Most of Boulder's open space trailheads lock down or enforce strict post-sunset access rules, making night exploration off-limits to solo wanderers. But once a month, when the moon hits full phase, the City of Boulder's Open Space and Mountain Parks (OSMP) department and Boulder County Parks and Open Space unlock the gates for small, naturalist-led excursions into preserves that are usually dark and empty.
The crown jewel of OSMP's night programming is the "Welcome the Night" full-moon hike, which climbs up toward a Flagstaff Summit overlook. The outing is carefully timed so you stand on the ridge right at twilight: to the west, the sun slips below the jagged line of the Continental Divide, while to the east, a swollen full moon clears the flat horizon of the plains. Further out on county turf, like Rabbit Mountain near Longmont, volunteer naturalists guide small groups through prairie terrain to observe how Great Horned Owls, bats, and coyotes take over the landscape after hours.
What it's like
You'll gather at dusk at a designated trailhead with roughly fifteen other hikers and a city or county naturalist. As soon as the twilight fades, headlamps flip to red-light mode to protect everyone's night vision and avoid spooking nocturnal wildlife. The walking pace is intentionally slow, pausing on ridge lines to watch the moonrise and listen to the landscape shift from day to night. Spots cap early on municipal booking sites, so register the moment dates drop, and bring heavy wind-resistant layers—temperatures plummet rapidly once you step onto an exposed mountain overlook after dark.
The move: Register for a full-moon hike, bring a red-filtered headlamp, and walk an after-hours trail together as a guide points out moonrise, owls, and the night-shifted landscape.
📍 Before you go These are scheduled, registration-required programs timed to the full moon with small participant caps; book early through the City/County activity registration sites and bring layers and a headlamp.
- 📍 Boulder & Boulder County Open Space
- 💸 $
- ⚡ Low-key
- 🌗 Outdoors
Where: Various trailheads (e.g., Flagstaff Summit; Rabbit Mountain, Longmont)
Hours: Added 2026-06-23 — confirm current hours before you go.
⚠ Seasonal or scheduled — always check before you go.
Pair it with
- Blue Sky Bistro at Rocky Mountain Metropolitan Airport — Pair an after-dark trail hike with a stop at this runway-side bistro in Broomfield to watch regional tarmac lights from inside the main terminal.
- Meow Wolf Denver: Adulti-Verse Late-Night — Trade quiet, real-world moonlight over the Flatirons for high-concept, artificial glowing corridors during Denver's 21+ late-night museum takeover.
- The Terrorium Shop — Follow up a night spent tracking nocturnal ecology with a visit to this Denver botanical-and-taxidermy shop filled with preserved specimens and live terrariums.
Good to know
Are the full moon night hikes free?
Yes, the guided programs are completely free, though out-of-county visitors may need to pay a small parking fee at certain city and county trailheads.
Do I need to sign up in advance?
Yes. Group sizes are strictly capped around 15 participants, and you must register online in advance through the City of Boulder or Boulder County activity registration portals.
Where do the hikes meet?
Trailheads rotate monthly across city and county open space, ranging from Flagstaff Mountain overlooks in Boulder to prairie preserves like Rabbit Mountain in Longmont.
What gear should I bring?
Pack a headlamp with a red-light filter, sturdy hiking footwear, water, and warm layers suited for mountain wind after sunset.
Plan a visit & invite your people →
Further reading: bouldercolorado.gov · bouldercounty.gov · discover.bouldercounty.gov · travelboulder.com
last checked: 2026-06-23