In this heat, even my 1.5 miles gets me sweaty, so I wear a different shirt for the ride and change when I get here. But I don't shower or anything.
It's best if there is a sheltered place to leave your bike, so your bike isn't sitting out in the rain and humidity. But do consider security. I know someone who kept his bike in his office. He didn't ride regularly, that's just where he kept it. He worked in a medical building and one day someone just wandered by and took it. It wasn't locked up or anything. So--lock your office when you're not in it.
2009 Trek 7.2FX WSD, brooks Champion Flyer S, commuter bike