We all know moisture from rain and humidity can be severely damaging to almost all photographic equipment, especially electronics and optics. But that does not mean you can't shoot confidently in wet weather. I've read numerous posts from people deathly afraid to take their gear out in the rain. Most good equipment isn't near as fragile as people think. You just need to take some precautions and then spend some effort afterwards drying everything out effectively.
Our area has been hit with tremdous wet weather over the last month or so. A local high school soccer match between cross town rivals was recently moved from the city stadium (grass) to a turf field at the away team's school facility it has gotten so bad. Yet the D810 and 70-200mm f/2.8 weren't phased to be out.
My recommendations include choosing your gear wisely. Most professional level gear is weather and dust sealed. Most consumer gear is not. Enthusiast level stuff tends to be sealed at least to some lesser extent than the professional. Find out and select wisely.
I don't own a premium rain cover for my camera/lenses. I use inexpensive Optech sleeves that run about $5 for 2. If you are out for long periods or don't have the abiity to get back into low humidity envronments immediately after a rain shoot, the better covers like ThinkTank stuff seems a wiser choice.
Wipe down and air out your wet equipment as soon as possible and for longer than you think in a low humidity environment.