In our previous article, we spoke in depth about the variety of celestial objects that you can observe in the 2025 Denver night skies. If you’re planning to stargaze in Denver, knowing when to look up is just as important as knowing what to look for. Here, we’ll break down when you should plan to look at these objects. Barring clear skies and cooperative weather, planning when to view an astronomical object or celestial event can typically depend on one or more factors: the phase of the moon, the position of the bodies in our solar system, and the seasonal location of the earth on its path around the sun. Here’s a guide to the best times in 2025 to observe the wonders of the night sky, organized by these categories. Be sure to also check out upcoming our post on Where to Explore the 2025 Denver Night Skies.

The Moon Phases

Regardless of whether the Moon is the target of your observation or an impediment to dark sky objects you’re trying to view, the Moon’s phases are an important factor in when to plan your observations. The Moon’s phases are not only visually captivating but also provide opportunities to observe specific lunar features. The terminator’s shifting shadows create a dynamic viewing experience throughout the month, making each phase of the Moon worth exploring.

• Craters and Mountains: These are best observed around the first and last quarter phases. The sharp shadows along the terminator (the line between light and dark) highlight the rugged lunar surface.
• Maria (Lunar Seas): These dark plains are most prominent during the waxing crescent and waning crescent phases when the sunlight glances across their surfaces.
• Full Moon: While the full moon washes out fainter celestial objects, its bright, fully illuminated surface is ideal for casual observation and photography.

Bold type indicates moon at perigee.

The 4 or so days on either side of a New Moon are the best times to plan for the viewing of fainter objects in the night sky to avoid the light pollution reflected by the moon. The Denver Astronomical Society plans Dark Sky Weekends that correspond to these times when the moon won’t impede observing at the Kline-Dodge Dark Sky Site in Deer Trail, east of Denver. These weekends are also when the DAS plans orientations for new members. Weather permitting, here are the planned Dark Sky Weekends at the Kline-Dodge Dark Sky Site.

Solar System Orbits

The planets and other celestial bodies in our solar system offer some of the most captivating sights for stargazers. Their visibility changes throughout the year as they move along their orbits, creating opportunities to observe unique features like Jupiter’s Great Red Spot, Saturn’s moons, or Venus shining brightly as either the evening or morning star. Whether you’re using the naked eye, binoculars, or a telescope, keeping track of the best times to view each planet will help you make the most of your stargazing sessions in 2025.

• Mercury: Best viewed during its greatest elongations from the Sun when Mercury is easiest to spot either in the evening or morning sky.
• Venus: Visible as the brilliant evening star in the first half of the year, reaching its greatest elongation on May 31. It transitions to the morning sky later in the year.
• Mars: Visible throughout much of the year, though its brightness diminishes as it moves farther from Earth. It’s best observed in the early months of 2025.
• Jupiter: Dominates the night sky from late evening to dawn for most of the year.
• Saturn: Best seen in the evening sky. However, in 2025, the rings are nearly edge-on and will be difficult to see, even with a telescope. Saturn’s moons, such as Titan, remain excellent targets for observation.
• Uranus and Neptune: These outer planets require binoculars or a telescope and are best viewed at opposition.

2025 Celestial Alignments:

January

• January 3: Conjunction of Venus and the Moon.
• January 5: Lunar occultation of Saturn. Visible from parts of Europe, Africa, western Russia, and eastern Greenland. A conjunction of the pair will be more broadly visible elsewhere.
• January 10: Venus at Greatest Eastern Elongation.
• January 13: C/2024 G3 (ATLAS) reaches perihelion. Around perihelion, it might be visible in the daytime sky in the northern hemisphere. Expected magnitude -1.9.
• January 14: Lunar occultation of Mars. Visible from the Americas and Africa. A conjunction of the pair will be more broadly visible elsewhere.
• January 14: Mars at Opposition.
• January 18: Conjunction of Venus and Saturn.
• Late-January – Mid-February: Venus, Mars, Jupiter, Saturn, Uranus, and Neptune are all visible in the night sky.

February

• February 1-2: Close approach of the Moon, Saturn, and Venus.
• February 6: Close approach M45 and the Moon.
• February 9: Conjunction of Mars and the Moon.

March

• March 6: Conjunction of Jupiter and the Moon.
• March 8: Mercury at Greatest Eastern Elongation.
• March 9: Conjunction of Mars and the Moon.
• March 14: Total lunar eclipse.

April

• April 5: Close encounter of Mars and the Moon.
• April 8: Conjunction of Venus, Saturn, and Mercury.
• April 21: Mercury at Greatest Western Elongation.
• April 25-26: Conjunction of the Moon, Venus, Saturn and Mercury.

May

• May 25-26: Conjunction Mars and the Moon.
• May 23: Conjunction of Saturn and the Moon.
• May 24: Conjunction of Venus and the Moon.
• May 31: Venus at Greatest Western Elongation.

June

• June 1: Conjunction Mars and the Moon.
• June 10: Lunar occultation of Antares and the Moon. 
• June 19: Conjunction of Saturn and the Moon.
• June 22: Close encounter of Venus and the Moon.
• June 30: Conjunction of the Moon and Mars.

July

• July 4: Mercury at Greatest Eastern Elongation.
• July 8: Venus near M45.
• July 16: Close encounter of Saturn and the Moon.

August

• August 11-14: Conjunction of Jupiter and Venus.
• August 12: Conjunction of Saturn and the Moon.
• August 19: Mercury at Greatest Western Elongation.

September

• September 8: Conjunction of Saturn and the Moon.
• September 17: Close approach of Jupiter and the Moon.
• September 19: Close approach of Venus and the Moon.
• September 21: Saturn at Opposition.
• September 23: Neptune at Opposition.

October

• October 5: Conjunction of Saturn and the Moon.
• October 14: Conjunction of Jupiter and the Moon.
• October 29: Mercury at Greatest Eastern Elongation.

November

• November 2: Conjunction of Saturn and the Moon.
• November 10-11: Conjunction of Jupiter and the Moon.
• November 12: Conjunction of Mars, Mercury, and Antares.
• November 21: Uranus at Opposition.
• November 21: Lunar occultation of Antares.
• November 29: Conjunction of Saturn and the Moon.

December

• December 7: Mercury at Greatest Western Elongation.
• December 7-8: Conjunction of Jupiter and the Moon

The Earth’s Seasons

The visibility of many constellations and the stars, clusters, galaxies, and nebula contained in their boundaries depends on the time of year, though some constellations are visible year-round in Denver:

• All Year Round: There are Circumpolar Constellations in the sky that never set below the horizon making them visible throughout the seasons. In Denver, they include Ursa Major (including the asterism of the Big Dipper), Ursa Minor (containing Polaris, the North Star), Cassiopeia, Cepheus, and Draco.
• Winter (January to March): Orion, Taurus, Gemini, Canis Major, Canis Minor, Auriga, Perseus, Lepus, Eridanus, and Monoceros dominate the evening sky.
• Spring (April to June): Virgo, Leo, Boötes, Hydra, Corvus, Crater, Libra, Canes Venatici, and Coma Berenices rise to prominence, along with the Big Dipper, which is high in the sky.
• Summer (July to September): The Summer Triangle—formed by Vega, Altair, and Deneb—is a highlight, along with Scorpius, Sagittarius, Ophiuchus, Hercules, Lyra, Cygnus, Aquila, Delphinus, and Vulpecula in the southern sky.
• Fall (October to December): Pegasus, Andromeda, Pisces, Aquarius, Aries, Cetus, Triangulum, Capricornus, and Pisces Austrinus take center stage. The Andromeda Galaxy is also well-placed for observation.

Also dependent on the seasons are the meteor showers that appear to radiate from specific constellations as the earth passes through the paths of comet or asteroid debris while orbiting the sun. These annual events provide dazzling displays. Here is a list of the best meteor showers of 2025:

Bold type indicates the strongest predicted showers. * Strong moonlight will interfere.

Keep Looking Up

Denver’s dark skies offer incredible opportunities for observation throughout 2025. Mark your calendars for these celestial events and plan your stargazing sessions accordingly. Be sure to read our companion posts where we dive into what objects and events to view in Denver for 2025 and the upcoming best locations in Denver and surrounding areas to observe these celestial targets, helping you make the most of your stargazing experience. Clear skies and happy stargazing!