Why is my iPhone 6 battery draining so fast?

I can get maybe 2-3 hrs of light use out of a full charge.. this just started about 45 days ago.. I have tried many things including deleting apps, closing out everything after use and making sure nothings open.. I don’t store anything on my phone, don’t do music and have roughly 200 pics.. safari seems to be the biggest drainer, I can watch the percentage go dwn by the minute.. my phone has been exposed to the cold a couple of times before this problem happened..