My set-up isn't quite as comfy as many here have theirs, and weather changes is the main factor to feeling that. I'm personally rooted to my area (Seattle) at the moment so whatever weather comes I deal with it.
Wind: I make sure to park away from trees or power lines. We do occasionally get brief, small twisters here but the main issue is just lots of trees, and especially if it's been raining a lot the soil gets waterlogged and then a windstorm blows down a bunch of them. I once moved spots when it became stormy only to find the next morning a massive branch had fallen in the exact spot I had been parked, temporarily closing the road. It would have dome serious damage to the van with me inside it.
Rain: I avoid parking directly under trees due to the larger raindrops dropping off them that are louder than normal rain. I turn on my little dehumidifier as much as I can to help help keep the play drier, and tend to seek more things do do that involve me being inside a building.
Cold: my setup doesn't currently have heater, and I'm very sensitive to cold. So far that means winters are somewhat miserable no matter what I do, but I have various strategies to improve it and it keeps getting better. One of the best investments I made was purchasing a high quality winter coat, gloves, and hat. I basically kept adding sleeping bags and liners to my sleep system until I could pile them up enough to stay warm. One of my sleeping bags is a thin cheap one that's slippery inside and out, and I get into it fully clothed to "hang out" in my van when not in bed, either in the front seat or in the back. If all else fails and I still get too cold I drive somewhere and blast the heat. Since I'm in a minivan, it's designed to blast heat to the back as well as the front so it helps a lot. Of course I have inserts in the windows to prevent heat loss there too. I've also had nights when my bf stays over primarily to help keep me warm, but that hasn't always been an option.
Heat: oh gosh. Well, I park in the shade if I can. I have a windshield insert to reflect the sun out and reduce heat gain. Inserts in the windows help. I have rain guards in my windows so I can crack them open without people noticing they're cracked. It still gets too hot in direct sunlight, and I plan to install a roof vent int eh future. In the meantime, my main strategy is 10" O2Cool fan that moves some serious air, paired with a water spray bottle i keep on hand. Temperatures inside easily reach 110*F and heat exhaustion is a real concern. My bf and I both got it a few times last summer and had to nurse each other through it. Having water in a spray bottle and the ability to create a stiff breeze makes a huge difference. Also, now that I have a fridge that works well I can keep a cold beverage in there at all times, which also makes a significant difference when overheating. Also: good air conditioning.
Do I ever get scared? Sometimes. Less and less the longer I do this. Getting heat exhaustion is scary, and I got severe hypothermia once when I was separated from the van in winter with insufficient clothing. I probably would have died if someone hadn't helped me, and though it was over a year ago I still suffer aftereffects from it. Having the large branch fall directly where my van had been was scary. But, each and every one of these things was preventable with basic common sense. I got the warm clothing and in winter never go anywhere without it. I got a digital thermometer to keep in my van to help me monitor how hot or cold it is, so I can adjust accordingly before things get too bad.
I actually find a good ol' rain and wind storm quite exciting; when I was living in a sticks and bricks house I would always try to find a way to be closer to it; now that I'm in my van I quite relish the sensations of the wind rocking me around and the rain and hail pelting the roof.
I feel energized by it. Oh, and try not to park anywhere where it's likely to get hit by lightning. Another common sense thing.
Weather definitely plays a significant role in my lifestyle, and while it's annoying some days to have my plans affected by it, sometimes it's kinda nice to have that eel of being closer to nature, especially since I live in the city.
