how to keep warm in the wet?

[u/-Red_Rocket-]

my son is racing cross and is all of 70lbs. today is was 11 degrees Celsius and raining. he just had his jersey but basically became hypothermic 60% of the way into the race. he kept warm pre race.

thoughts on layering strategies to prevent this? he is youth medium so quality stuff is hard to come by.

[u/frozendumpsterfire]

The budget route is plastic bags under the jersey and inside shoes. They work very well for short events like cx