It is not currently snowing in Big Bear Lake, but the ski resorts make their own snow anyway so there is plenty to ski on. Here is a link to some webcams (it is dark now so they are black). There is snow on the ground it is just not actively snowing.
Depending on your location, you should first find out what the weather will be like, so that you know what to wear. If it will be cold, you can put on some skinny jeans, a warm sweater, and maybe some boots. If it will be sunny, you can wear a pair of shorts, a light top/T-shirt, and a pair of sandals.