Northern Lights Tonight in Castle Rock, Colorado

Live visibility odds for Castle Rock, combining the current geomagnetic Kp index with real local cloud cover, not just one or the other.

What Kp do you need in Castle Rock?

Those frequencies are how often the geomagnetic threshold itself is reached, before weather. Cloud cover, moonlight and local light pollution all cut into it, which is why the live score at the top of this page multiplies the geomagnetic odds by tonight's actual sky over Castle Rock.

Which way to look from Castle Rock

Face north. From Castle Rock the auroral oval sits well to the north, so activity shows up as a glow low on the northern horizon rather than overhead — which means a clear, unobstructed northern view matters more here than total darkness does.

Best time of year

Aurora season in Castle Rock runs from late August through April, for the simple reason that you need genuine darkness and summer nights are too short and too bright. Activity clusters around the equinoxes — late September and late March are statistically the most active weeks of the year, an effect of how Earth's magnetic field lines up with the solar wind at those points in the orbit.

Will I see the aurora in Castle Rock tonight?

Right now, Castle Rock has a 0% chance based on tonight's real conditions: Kp 2.7 and 70% clear skies. Unlikely. This updates live, so check back closer to dark for the most accurate read, especially if the sky is currently cloudy where you are.

A good Kp forecast isn't the whole story. See what else actually determines whether you'll see it →