Prevailing weather is one of the factors when choosing a tent but so is exposition when camping. In Europe, it's too common to camp in very exposed places, consistently, day after day if you're on a long route, well beyond the known weather forecast. It's a matter of population density and the fact that most of western Europe is so urbanized the only wild-ish places are high in the mountains. In North America, camping in protected locations is much more often an option, a good option.
I'd agree with this. Most of the members here are from the States, so of course the perception of where most people camp is going to be highly affected by the kinds of places that most people camp in in the States. But the US (and Australia) just doesn't have the population density that Europe (or here in Japan) does. That's going to leave you mostly camping very high up, away from the reaches of civilization below.
One of our regular BPL contributors usually reports the same for Japan.
Heh, heh... I take it that is me (though it could be Arapiles as well). Japan is so crowded and so tight land-wise, that the only places you can get away and do real backpacking is from 1,000 meters (3,000 feet) and up. Most of my camping is around 2,000 meters (6,000 ft). Since the mountains in Japan are extremely steep, flat ground is at a premium, and often those tend to be in very exposed saddles or ridges. So when you bring a shelter in Japan it must be able to handle high winds and very heavy rains. Going floor less in Japan often means sitting in ankle deep puddles or mud since you often have no choice of where to set down your shelter in the crowded camp grounds. People do use tunnel tents more these days, and they are what I use exclusively whenever I go hiking in Europe, but tunnels need big footprints for the many (very useful and effective) guy lines. More often than not I end up having to scramble in the bamboo grass and impenetrable creeping pine surrounding the scrape of flat open ground for the shelter, to try to get the pegs in and not succeeding. So smaller, alpine-style dome tents tend to be the most popular designs here in Japan. Most tarps and tarp tents would get blown to smithereens in the heavy winds, or the tendency to be pitched with exposed sides makes them very cold or wet inside with the side-blown rain. Recently, UL'ers have tended to go with enclosed pyramids like the Locus Gear Khufu, precisely because they have small footprints, can be stable with shorter guy lines, and can be pitched right to the ground.
I'd still prefer tunnel tents, though. For their weight they have so much more usable room than any other design. And they are so easy to pitch in any weather. During my wife and my 6-month bicycle journey around Europe we started with a geodesic dome tent, but it was so heavy and ungainly to carry around, that we sent it home and bought a tunnel tent for the rest of the trip. No matter what the weather it always performed perfectly, even way up north in the Shetlands, Norway, Sweden, and Scotland. During storms we'd make sure to set all the guy lines (double, like Roger suggested), crawl way back into the back of the tent, and lie on our mattresses reading books or napping while the front door was open and the storm lashed about.