We definitely use our grill all year long, but winters are pretty temperate here. I've definitely stood over the grill with an umbrella in the rain, though. Can't beat that fresh-grilled taste, as Fullerman5000 said.
My father, who lives in a climate where it doesn't snow, uses it year around. He's really big on barbequing. It could be forty degrees outside and pouring rain and he'll be on his patio making ribs. He doesn't care if everyone else is inside huddling near the heater, if he wants to make ribs, he's making ribs.
The lid sports a hefty dent, the legs are wobbly but my tabletop grill has had a good life. It has seen its share of tasty ribs, succulent steaks and more hamburgers than can be counted. Though I have a great gas range in my motorhome, I use the grill almost exclusively.
As others have said; meats just taste better cooked outside over direct flame as do many veggies and corn on the cob. Also as I live full time in a motorhome, using the grill eliminates food odors inside that are intensified by the smaller confines.
I love the smoky aroma of a grill heating up and the anticipation of the rewards it soon will bring forth.
Living in the UK we use our grill about twice a year if we are lucky. We just get so much rain! and you can never plan to have a BBQ. If it's a nice day it's quick get out the grill and get some friends over.