It will depend on how comfortable you are on your skis or snowboard. When it is warm like this the snow will be very wet as it melts. If you are confident it can be plenty warm in just a sweatshirt or maybe even a tshirt. If you fall, however, you can get soaked through really easily unless you have a good coat and gloves. Once you are wet it's really hard to warm up!
Yes,you will need your snow suit and gloves.Coat,hat maybe optional ,but still better to go with them.you can leave them in the car if it turns out you don't need them
It wouldn't hurt too bring it, but you probably won't feel the need to wear it all after you've been there awhile.
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