Thread title is pretty self-explanatory. Being from New England, and having no hurricane/tropical storm experience, I must ask- should you remove them? I can easily believe that high winds could wreak some havoc with them, but removing them all over the house would be quite a production that I wouldn’t want to do unless necessary.
Thanks for your input, more hurricane-savvy dopers! I’ll be sure to return the favor next time you guys get a noreaster in Florida. 
If you’re worried about water penetration you could wrap & tape large plastic leaf bags over the outside of the window AC. I did that every winter for years to block cold air from my window units. Pull the plastic tight & tape with duct tape so the wind doesn’t grab it.
Wind? I’m not sure. Seems like anything that would grab the AC would grab the roof too. I’ve never heard of anyone removing window AC units before a storm.
We’ve had 80 mph winds here with gusts into the 90’s (even once to 100 mph!) and our window AC’s stayed put, no problem. Granted, it wasn’t a full onslaught hurricane, but it was no trifle of a storm, either. Those units are usually pretty solidly set in the window. I’d only worry about it if I had a unit that wasn’t firmly in place.
I agree, wrapping them might be a good idea.
If I were you, I’d spend the time left before the storm boarding up windows and checking my emergency kit.
On the other hand, if someone from Florida pops in and says different, well, they’re the ones with hurricane experience.
I’m taking mine out. The seal between the window and the air conditioner is just a little foam rubber, so if the rain goes sideways, I am afraid it will leak. It is easier for me to take them out and secure the weatherproof windows, than to try to wrap and tape the air conditioners so as to be weatherproof (I don’t even know if that is possible on the second floor).
I took one out, left one in, the reason is sometimes in very heavy rain one would tend to leak inside the house. Also the one I removed is a small easy to remove a/c.
Thanks for the responses everyone. Emergency supplies are in order and it’s already started raining, so I guess I’m good for now. I’m a little worried about the foam rubber parts on either side of the A/Cs blowing out, so I’ll probably reinforce those with duct tape/cardboard and call it a night. I just didn’t know if removing ACs was one of those things people do in advance of a storm. Seems not to be, thankfully.
Hope everyone in the path stays safe.
For what it’s worth, we took ours out, and so did our neighrbor behind our house. Although our next-door neighbor didn’t.
If your neighborhood is likely to be evacuated, and thus temporarily somewhat lawless, removal might be a good idea.
Years ago, I knew a professional thief. One of his easiest targets was window ACs. They are usually easy to bag from the bed of a pickup truck in broad daylight, I was told. The neighbors assume the thieves are repairmen.
In any case, don’t delay your own evacuation to save your AC unit. Your own safety is much more valuable.
Judging by the 50-knot windspeed probabilities, the NOAA seems to think that Irene will have tropical storm force winds when it reaches Boston. My guess is that reinforcing the side panels is enough.
I’m a good ways inland (>10 miles from Boston Harbor), so everyone’s pretty much just hunkering down. Most people seem rather unfazed by the whole affair, but I’m trying to be prudent. Grocery stores and the ilk are closing, however.
Thanks for your concern, though! No life is worth a $150 hunk of metal.
It’ll be interesting to see what happens. We haven’t gotten a hurricane that amounted to more than a thunderstorm in my lifetime.
With the thousands of in-window ACs in apartments in NYC, I figure if there was any type of danger the news channels would have been all over warning people to remove them. I haven’t heard them mentioned once.