Is the Canon 60D weather proof? I know it is not stated in the manual, but has anyone tried using it under light rain?
Most cameras are more weatherproof than their manufacturers let on. The problem is that most users expect that "weatherproof" means it'll be ok if left out in a rainstorm like a forgotten toy, which is very much not true.
In my experience, any camera will easily survive a light snowstorm or light misting rain while slung over your shoulder or around the neck for short durations without any trouble. I've also used several cameras that are not waterproof or weatherproof in very bad conditions simply by keeping them protected until I'm ready to take a photo, then putting it away -- and never had a problem.
Weatherproofing protects your camera just a little more: it's just a little extra insurance to let you shoot in less than ideal situations. Dusty conditions, in particular, are helped by weatherproofing because the seals keep out the tiny dirt that can make a button gritty, for example. Weatherproofing will technically help keep water out in adverse conditions, but if you have the ability to shield the camera in such storms you'll be well off, too.
Note that you've specifically asked about the camera body only. Consider your lenses, too, which actually have more area for water to get in around the rings, focus extension, zoom extension, etc. That's the thing to really be concerned with, IMO.
Basically no. Canon offers varying degrees of weather sealing on their cameras and the 60D has some sealing, but I would not use it in rain, beyond a light mist. They do make bags you can put around your camera and lens if absolutely necessary.
You can get an idea of where the 60D is sealed in this review (callout near the bottom) http://www.imaging-resource.com/PRODS/E60D/E60DA.HTM
And as mentioned, don't forget the lens! For Canon, you won't see any serious sealing below L class lenses, and even there it's not universal.
Canon claims that 60D is as much weatherproof as 50D, but for weather resistance - it just feels better to hold a magnesium alloy body like the 7d over a plastic/fiber-glass one like 60D. There are certain limits of water-splash or rain upto which these bodies may survive from and usually the newer bodies (with magnesium alloy chassis) performs better.
And one more thing, weather proof doesn't mean that it's water proof at 100%. If you submerge it in water without a proper waterproof casing, chances are very very high that it will damage.
In my experience the combination 60D w/ EF 50mm f/1.8 STM is sealed to a great degree. My family went to Niagara falls during June 2017 and I used it for a tour of the falls from the Canadian side. Reading that this camera had weatherproofing, I used it as my workhorse for pictures and video. The walking section of the tour placed you adjacent to bottom of Horseshoe Falls, we got drenched. I used the camera to take pictures and got some great shots. We then took a ride to the falls from the Canadian side, which now gets you spitting distance to horseshoe falls. I used it for pictures and video. It worked amazingly. The only accessory on the camera was the neck lanyard. Granted I could be a very lucky guy, but I have shot with Canon products in many different types of weather in Austin Texas for the last 20 years and have not been disappointed.
I have discovered that the 60D is not, in fact, weather sealed. At one point I started seeing dust and a small eyelash-like hair inside my viewfinder. I could not get it off even after intense blowing at the mirror. The only incident I had before that was being splashed by a rough sea in a boat in the Philippines.
So I found that this needed work on the focusing screen. I took it to Canon Singapore who refused to cover it under warranty, and categorically denied it being weather sealed. I would take this as official. Note that the body is manufactured in Japan.
It cost me S$45 or so. The sadder part is that less than a year later, I see dirt in the same place and I would have to pay again to get it cleaned.