Telescopes are not magical instruments - they cannot see through clouds!
If it's overcast we won't be able to show you anything in the sky. However, unless the weather is truly inclement, we'll be around during open houses for at least 30 minutes after the scheduled starting time to show visitors around the observatory and let you at least look at the telescopes, if not through them.
If you're uncertain as to whether or not we'll be open, you can call the Observing Deck at 303.492.2020 (no earlier than 30 minutes before the scheduled starting time) before making the trip to the Observatory. You may or may not get an answer, depending upon whether a host has arrived and/or whether s/he is able to take the time to get to the telephone.
We can't predict the weather, so please avoid calling us to ask if the skies will be clear. Your best bet will be to check the local forecast or simply go outside and look up.