I don't see why not. How windy is it? An alternative might be a bamboo/grass shade that rolls down from the top.

We blocked sun with a roll down Coolaroo shade (Lowes). Husband mounted it to the frame. Make sure you get the manual roll down with a crank. We used short bungee cords and weights to hold the shade flat down when extended because our area is so.......windy.

Good possibilities from Jinx and colonel. You might also check Sunbrella outdoor curtains, although they're likely pricey.

During the pandemic i made outdoor curtains from drop cloths and a grommet kit. Was so happy with them i have kept them in use even when other options have been available.

We weight ours down with bricks when needed for windy/rainy nights.

You can buy curtains made for the outdoors from lots of places. Google it.

Shower curtains are not going to be long enough. If you are looking for protection from the sun then the Coolaroo shade can be purchased at HD or Lowes off the shelf.

There are curtains made for pergolas, but they blow in the wind. These are from Kohls.

Thanks folks! I'm aware that outdoor curtains exist, it's just the length I need is actually the exact height of a long shower curtain, so that makes it nice and simple. Appreciate the products you've shared, not all are available in Canada unfortunately.

Try the shower curtains for a season and see what you think. You can keep looking for other alternatives for next season over the winter if you're not pleased with them.

IMO a drop down solar shade is the perfect answer and really everything is available in Canada maybe just a different name. BTW Amazon.ca has tons of outdoor curtains

I've used fabric shower curtains for privacy on my balcony for years. They filter light, but still let a lot through, so if blocking light is your goal, they may not be a good choice. I've used the same ones for multiple years and had no issues with mold, just take them down and wash as needed.

Fabric store. Go there. Look for heavy weight canvass, kinda like what sails are made of. It probably comes in colors. If not, you can paint on it. You can buy any length you need. Just need to know how to keep it from fraying, possibly fusible facing if you can't sew a straight seam. Then hang them with stainless hooks.

Yes, you can. I bought the 100% polyester fabric shower curtain liners from Superstore and they are still perfect five seasons later. Mine are light grey so the don't look dirty. I throw them in the washer once or twice a season to freshen them up. Keep in mind that they are super light weight so you will need a method to weight them or tie them down. For me it was easy, I just binder clips them to my  cable deck railing. Since they are polyester, they have never gotten moldy or mildewed - but I am in a low humidity province.