Dress warmly (especially for evening programs) and bring your reservation confirmation with you. The Visitors Center is currently open for daytime General Admission and Guided Tours. The Visitors Center's phone number is 432-426-3640.
When to Visit
There is no single best answer to this question, but there are several factors to keep in mind:
If you plan on attending a Star Party, consider the phase of the Moon. With the Moon at any phase between several days before First Quarter and 3 or 4 days past Full, bright moonlight limits our ability to observe faint objects but, of course, gives us great views of the Moon itself. You can see a calendar of Moon phases at StarDate Online to help you make your plans. For exact phase dates & times, go to the U.S. Naval Observatory's moonphase page.
Though we can't predict the weather if you're visiting us weeks or months in the future, you can get some idea of what to expect by checking out our links to some of our favorite weather information sites.
Also keep in mind that our Star Parties draw the largest crowds of the year during Spring Break, which generally falls within the second and third weeks of March. Star Parties held during this time can draw more than 500 visitors! In contrast, the winter months produce the smallest crowds at McDonald Observatory but, of course, occasionally bring us snow and ice.