How do I make outdoor curtains for my patio in Arizona?

Diana, here's what I use. Drop Cloths! Just get them at Lowe's or Home Depot or any place like that. They come in several sizes, just get the size that best fits the area you need them for. You might have to sew a rod pocket in them or you can use clip hooks, I've done both. Good luck.

https://www.youtube.com/results?search_query=patio+curtains+from+drop+cloths

Outdoor awning materials like RVroll out awnings are made of is one fabric to look for. This material is actually 2 layers of vinyl bonded together with threads in the sandwich middle for strength. it is heavy & very strong. However, even at best, you will likely need to replace them about every 3 years due to Sun & heat damages. It isn't cheap but you might try looking on Amazon or eBay. I do not recommend cotton canvas drop cloth products as the sun, heat, ,& wind will destroy it very quickly.

One other option a little less expensive is outdoor shade cloth. Home improvement stores carry this in rolls or pieces. It will take weather beating, but again, the sun will deteriorate the vinyl fabric & you will likely need to replace this about 1 to 2 years. The heat & wind just does this to all fabrics.

If costs is a factor, you might want to consider using 100% polyester fabric curtains & just plan on 6mos to yearly replacements. Shower curtains & even table cloths you can convert or hang & often find in thrift & resale shops cheap may work for you.

Wish I could tell you something better& longer lasting, but there just isn't anything I know of that will last any longer exposed to those AZ inclinate weather elements. I know how they are given I lived in AZ many yrs ago. I wish you the best & much success with your project!

The Best fabric to use is muslin or use canvas