As long as you're not riding through a field you should be ok. Also, you're not grounded while on the bike (rubber tires) so you wouldn't get struck. I would worry about visibility and traction. We've been getting scattered storms the past two days (NYC) and I'm riding home tonight. It's mostly bike paths/lanes so I'll just have to worry about getting soaked and not taking a spill if I'm caught in a storm.