How to anticipate outdoor lighting (sun angle) 2.5 months from now?

Hi all, I'm a "regular" lurker jumping in with a weird question. I'm a puppeteer designing for an outdoor amphitheater show, end of July/early August in Colorado. The show will start about 2 hours before sunset and only run for 50". I'd like to include some shadow work but don't know how well I can estimate how much sunlight we'll be fighting. If I do some workshopping now, (2 hours before current sunset time) might the angle of the sun change enough end of July to cause unanticipated problems? The theater faces a tad west of north and there are mountains to the west, so angle changes could potentially have significant impact. Our costumer thought there might be an app for this (determining the position of the sun for a given date/location?) If not, who would be knowledgeable about this sort of thing? TIA!

Try this: https://photoephemeris.com/en

If north is "UP" in your picture and your audience area is the grass "north" of what looks like a covered stage facing "a tad west of north," the sun will be at its northernmost point on 21 June and will be on its way south again by late July-early August. Standing in your house facing your stage (a tad east of south) the sun will be pretty high in the sky and hitting the right side of the audience's face as it sets. I'd guess that you'd need some pretty bright lights on your puppets throw contrasty, sharp shadows on a screen facing the audience. Skylight will be the biggest problem, decreasing as the sun sets. The farther upstage and the more shading you can provide for the screen i.e., the least skylight possible, the better.

There are a decent number of free/cheap astronomy apps that can show you the position of things (including the sun) at any future date.

While it's not exact it sounds like your show is around 6 weeks after the solstice on June 21, we are around 6 weeks before the solstice now so the sun position is likely to be similar but as usual there are various complicating factors that may or may not be large enough to matter.

Wolfie's suggestion of Photo Ephemeris is the correct answer here. It is used by photographers to know the direction and angle of the sun's light, for planning outdoor shoots. The iOS app even has an Augmented reality feature, that will show you the position of the sun on any date at any time. It is incredibly helpful when planning for any outdoor events!

Thank you all, very much! Photo Ephemeris is great and has given me the confidence to move forward with this idea. Thanks, Wolfie!