If someone were inclined to turn off only some weather effects, I would certainly recommend lightning. You can select at least weather severity just from the core menu. Severe weather like thunderstorms and blizzards are optional. Lightning has cost me a fortune from having to replace things like outdoor lighting, at least one bee box, and a Patchy the Straw Man. My Sims have also gotten struck a few times, but thanks to a Trait purchased from the Aspiration Rewards, they actually like it. The Storm Chaser Trait gives them positive Moodlets rather than negative (like "That Was Totally Awesome!"). Some mild weather can actually be beneficial and amusing and are worth keeping. For instance, rain waters your plants for you and you can even choose to "Shower in the Rain".