Can I use this outside, in the backyard in the daytime?

Since this is a projector screen, maybe daytime is not the best moment, but it depends on the projector used. It can definitely be used outside (recommended after dark) and most likely you will need a tripod, unless you use your own engineering technique, like a home-built wooden structure or stand to hold it up. Of course, you can use the very strong Velcro, and build a frame for it if you’re not attaching it to a wall. Some clients prefer to hang hooks to the house and use a grommet kit to make holes so they would not rip the screen.

For more information please check out our guide setting up a great backyard setup
http://outdoormoviehq.com/ultimate-guide-to-outdoor-movies
Or take a look at our recommended projectors and screens
http://outdoormoviehq.com/outdoor-movie-screens