Re:
"I live in the desert"
I grew up in Utah. Not much rain at lower elevations and bone dry, but go up to the Uinta or even the Wasatch mountains and it rains/snows almost every day. Relative humidity is high there as well.
If you live in a desert, you can always head for the hills to experience some weather.
Or you can practice different pitches and visualize different scenarios. I know it sounds goofy. By doing so, you can estimate just how much shelter you really need.
When I was young, my shelter was a big painters tarp. The more I used it, the more I found ways to pitch it and the smaller it got. I think in the end, I was carrying something about 5'x9'.
But in Utah, I rarely had to pitch it and mostly cowboy camped.
I still often use a 5×9 if the forecast isn't so bad, but now that I live in the North East, I tend to gravitate towards a mid as they tend to be easier/quicker to setup at the cost of a little more weight and less flexibility.
It always seems to rain at night around here, or at least the dew is so bad that it can soak my sleeping bag. So cowboy camping is not as common.
This is not only important for backpacking, but as you know bicycle and canoe/kayak trips as well.