Winter Blankets? HELP!!

So I know its only October but lately us here in New York have been having super weird weather! (an inch of snow yesterday and there calling for 8-15 in of snow tomorrow!) it hasnt been too drastically cold but it hasnt been pleasently warm either.
Now next week its suppose to be in the 50's. My poor app has barely any coat, I mean its there but I feel like its not as thick as id like it to be. So im thinking he might need a blanket this year. Especially because he came from the auction down in Pennsylvania and im assuming he came from down south before that, and there winters arent nearly as chilly and crappy as ours up here.- now I don't usually like putting blankies on my horses at all. But that also depends on how well of a coat they grow. My app is out on 24/7 turnout with a huge run in shed.
Now all of this being said do you guys think I should atleast buy him a waterproof sheet or blankie? I really don't wana put a full blown heavy weight blanket on him because next year I don't plan on putting a blankie on him. If anything id really just like to give him something that will keep him dry but with a little bit of padding to keep him warm. I just don't want a heavy weight blanket on him. (sorry im not good with the whole blanket thing! I usually never put one on my horse.)
SO. This being said, what do you guys think? Should I just go and buy him a heavy weight blanket, or just stick with a waterproof sheet,?...or should I just wait it out and see if he grows a bigger coat? Any suggestions would be helpful!

Well, is he actually cold? I mean, when its bad outside do you go out and feel his skin? Is he shivering? Is he retaining heat?

If he is still warm and isn't in any discomfort, then I'd personally leave him be. If he doesn't have shelter (like mine, unless trees count) then I'd give a medium waterproof blanket at night or during freezing rain/snow (to keep from getting wet which makes it worse).

It's currently VERY cold rain outside tonight, so Indie is wearing her blanket.

How long have you had him? Has he had any time acclimating to this crazy fall we are having? Not sure where you are in NY, but our horses here in the Fingerlakes have been wearing their turnout sheets more than usual for october. They also have turnouts.....but it has just been SO wet. I have a draft cross, and even he, who is really warm usually has needed it. WE are also on top of a hill, so we get more wind than most, so mine are blanketed in winter. How much depends upon the horse. My clyde cross never gets more than a midweight. Some of the TB's get heavy weights since their coats are not as thick.
So, if this is your guys first winter here, I would recommend a turnout, and then maybe a blanket. Depends on wind, etc. I also just like blankets on mine, so I don;t always have to demuddify them.

Too bad you don;t already have one. Your horse probably could have used it the last couple of days and this weekend!

im about an hour from NYC. And I've had my horse since last saturday and before I got him he was in NJ then before that in PA then previos to that is unknown but im assuming he came from way down south. He doesnt seem cold but I've been worrying about him in this weird weather lately. If there was no snow I would just let him be and see if he grows a nice coat but snow-in October is kinda pushing I think for him. Also his paddock is on a steep hill so im sure hell catch most of the wind up there. What blanket would you recommend for him? I've been looking at mid-weights and below for him. I just worry if he's wet and then the rain and snow if he catchs a chill. Blah. This weather is rediculous. I also don't want to spend too much because I don't plan on using it next year.

I have had really good luck with the Riders brand from Dover. If you get too inexpensive you run the risk of it not being waterproof enough, and the denier (thread count-higher number=better and tougher from bites, tears, etc)is low so it may not make it through the season, leaving you in the lurch midwinter when noone has blankets left. Not to say something won't happen to a 1000-1200D (denier) but it is less likely. I think the riders are also affordable.
Here is the mid weight
Rider’s International Supreme Heavyweight Turnout Blanket < Heavy Turnout Blankets < Horse Blankets & Sheets|Dover Saddlery.
Not sure why I am not finding the t/o sheet that matches. The 1200 D one, with gussets, tail flap and leg straps.....hmmmmmm Riders brand. Maybe bc I am too tired.....

ETA-See-I screwed it up! That is the HEAVYWEIGHT. Their is a sheet, midweight and this. Nite

My mare had a midweight version of that!!! LOVE it. Has been through rolling, galloping, scratching, and all else for two years and STILL works like new.

I suggest buying a heavy duty rain sheet (one that will last) and a fleece liner / cooler to put underneath. The sheet will keep your horse dry and the fleece can be used to layer up if your horse gets cold. You may never need to use these, but you will feel much better knowing you have them just in case. You can also layer up as needed with the two separate pieces of clothing as opposed to one overly warm winter blanket. Like others have said, check to see if your horse is actually cold and wet to the skin.