Well I know a way that you can stay warm and still wear your favorite Spider-Man costume (costumes that show a lot of skin discluded.)
Disclaimer: G3 Cosplay Experience and all involved parties are not responsible for any sickness, injury, lack of expected result or death from use of our method. We are not claiming to be experts in this, this is simply a suggestion of something that has worked for us in the past!
Here are our suggestions for keeping warm. You can use one or a combination for MAXIMUM HEAT!
1. Thermal Underwear
Thermal clothes is normal used for staying warm while camping, but they're also great with keeping you warm under a costume.
2. Under-armor/exercise cloths
Under-armor does a great job of wicking away sweat and keep you warm while working out. So why wouldn't it work to wear it under your costume.
3. Layering
Layering clothes underneath your costume is always a great way to stay warm.
4. A Combination
If you're going to combine the tactics we suggest, put on your under armor first to wick away sweat, than the thermal clothes, (with as many layers as to make you at ULTIMATE WARMTH) and than put on your costume! And there you go! A nice warm costume without risking losing the accuracy and look of your amazing costume! Don't forget to stay awesome Kosplayers and HAPPY HALLOWEEN!!!!!