I saw this online & reminded me of my Father!
I have friends who are really dedicated to their grilling. I could see some of them doing this, too.
Thankfully, we have BBQ covers on ours, so my husband or son can also BBQ in the rain, but they have the advantage of coming indoors throughout the process. We (and by we, I mean they) BBQ year-round - just like the mailman, "through rain, sleet and snow".
I love summer, because not being a big cooking enthusiasm (have I mentioned that at least a thousand times?), I get to turn a lot of the cooking over to my husband and his grill. Fantastic!