My iPhone 5 was lost in the snow, then found and it doesn't even turn on anymore after it worked for 5 days??

I lost my phone a few days ago when it fell out of my bag but then someone found it in the snow. Not sure how wet it was when the person found it but my phone worked fine for 5 days after. When I plugged my phone in to charge over night, I woke up with it completely shut off and I can't even turn it on. Not sure if this is a water damage issue due to the phone being lost in snow or if something else could be the case. Its just strange that it worked perfectly fine for the past 5 days and now I can't even turn it on.
Any insight would be helpful!

It probably had moisture inside, and as you used it you caused the moisture to short out critical components.  You can take your iPhone to an Apple Store for diagnostics, but if the moisture indicators are tripped (and they probably are) it would need to be an out of warranty repair, or if you have it, one for the $79 Apple Care+ "incidents".  If you have to pay the full price for an out of warranty repair, that will run you much closer to $269 USD.