Though you could take your TV outside for a movie night, it won't have the same "wooow" factor as a projector. So finding the perfect projector should be your first step in planning your backyard movie night. The important factor to remember is that there is no one-size-fits-all projector for every use.
Instead, consider where and how you'll be using your projector. Is this simply for your backyard, or do you want something to take camping with you? It'll be best to choose one that is small enough to take outside and set on a table, but not so little that it won't provide enough light to illuminate your screen. Some portable projectors also include a built-in battery, but a long garden extension cord could also do the job.
Another thing to think about is the source material. What will you be watching? Or, more importantly, how will you watch it? The days of bringing a DVD or Blu-ray player out to the yard along with the projector are virtually gone. Sure, you could do it, but there are way more convenient solutions.
You can find projectors with built-in streaming apps or you can use streaming sticks or your laptop. Whatever you choose, make sure you have a good HDMI cable or reliable and strong WiFi, so you can view your movie with no lagging.
Some video projectors have a built-in amplifier and speaker, but the output level is designed for small rooms, such as conference rooms and classrooms. However, if you have a large yard or any kind of background noise, it may be difficult to hear. But with outdoor speakers connected to your home projector, you can have incredible sound to match your huge screen!