water/weather profing the leonardo chip

I was hoping someone could tell me if it is ok to wrap a leonardo chip in foam and then cover with waterproffing material for outdoor all weather testing? Does it need air flow for cooling? Very appreciated

What power source were you planning to use? The part that usually gets hottest is the voltage regulator and that gets worse the higher the source voltage is above 7V. If you are powering off USB then the regulator won't get hot.

Possibly place in an enclosure of some kind, plastic, metal , sealed?

And possibly use a conformal coating:

http://tinyurl.com/na7yjqm

It rather depends how long it will be left outside…

How about putting it in a well sealed container with a bag of desiccant?

..... but as long as you do not give any details, it is impossible to give you a reasonable answer.