When days grow shorter and the Rocky Mountains don a fresh coat of snow, Boulder’s winter sky truly shines. Many people shy away from stargazing in the cold, but winter nights bring some of the clearest, brightest views of the cosmos — and with the sun setting so early you don’t have to stay up until midnight to enjoy them! So, bundle up, grab a warm drink, and let’s explore why winter might just be the best stargazing season of the year.

1. Earlier Nights, Easier Evenings

One obvious perk of winter astronomy is that darkness falls sooner. While summer stargazers often have to wait until 10 or 11 p.m. for the sky to fully darken, winter skies are ready by dinnertime. That means more stargazing before bedtime — perfect for families and anyone who prefers an early night.

2. Crisp, Clear Air

Though Boulder’s temperature can drop significantly, that cold air often comes with a big advantage: steady, stable skies. Dense, cool air tends to reduce atmospheric turbulence, giving you sharper views of planets, stars, and deep-sky objects. If you can brave the cold, you’ll be rewarded with some of the most detailed observations of the entire year.

3. A Star-Studded Winter Showcase

So what’s out there to see right now?  Winter nights are jam-packed with celestial wonders:

• The Seven Sisters (Pleiades): High overhead, this open star cluster appears as a tight knot of bright stars. Most people can see six, but a truly dark sky might reveal the elusive seventh sister.
• Orion & Sirius: Orion dominates winter evenings with its iconic belt. Follow that belt’s line downward to find Sirius, the brightest star in our night sky, twinkling in the south.
• Gemini & Taurus: Look for the twin stars Castor and Pollux in Gemini, and the red eye of Taurus (Aldebaran) shielding the Pleiades from Orion’s pursuit.
• Deep-Sky Treasures: The Orion Nebula (in Orion’s sword) offers a stellar nursery through binoculars or a small telescope, while the Andromeda Galaxy hovers overhead, our closest galactic neighbor visible with just your eyes.
• Jupiter: Jupiter hangs bright throughout winter 2025, shining as a brilliant “star” and providing excellent telescope views of its dynamic cloud bands and four major moons.

Tip: Don’t miss the Full Moon/Mars occultation mid-month, and other events highlighted by NASA according to NASA’s January 2025 skywatching guide,.

4. Mars at Its Winter Best

Speaking of Mars, it reaches a prime viewing stage this winter. The Red Planet is at opposition on January 16, 2025, making it bigger and brighter than usual. For more details on how best to see it, check out my previous article, “Mars at Opposition: See the Red Planet at Its Best.” With the crisp winter air, you might even glimpse its polar ice cap or surface markings through a decent telescope.

5. Surviving Boulder’s Cold Nights

• Dress in Layers: Colorado nights can be deceptively chilly, especially after sundown. A warm coat, hat, gloves, and sturdy boots are your best friends.
• Bring a Blanket & Chair: Standing in one spot can get uncomfortable fast. Reclining on a camping chair or lying on an insulated pad prevents the cold ground from zapping your heat.
• Use Red Lights: A standard flashlight wrecks your night vision for up to 30 minutes. Opt for a red flashlight (or a dim phone screen with red filters) so you can see while preserving your ability to spot faint objects.

Enjoy It with AstroTours.org

If you’d like a guided experience, AstroTours.org hosts programs throughout the season. We provide telescopes, lights, and a professional astronomer guide while we walk you through each constellation’s myths, science, and must-see highlights.

Remember: Winter might require a little extra determination, but those brisk nights reward you with some of the most pristine stargazing Colorado has to offer. So grab your gear, step into the cold, and let the cosmos show you why winter is a stargazer’s secret delight.

Stay warm and keep looking up, Boulder!