I have a yearling, I'm not going to clip her, she lives in Maryland.  I would like to buy a turnout sheet so she'll have a little protection from the wind and snow, seeing as how there isn't a run-in shed in her paddock.  Should I buy a light weight or medium weight sheet? 

 If you have the money I would get both.  Maryland can get a bit chilly, and with no run-in she needs protection.  I have a soon to be 8 month old, and I am planning to get a medium-weight for him (I live in a warmer area and he has access to the barn, and he still has thick baby-type fur).  Good luck with her! Oh, and if she hasn't worn a blanket before be ready for some snorting and dancing to go along with the experience.

I would go with what crittergirl said, but if you don't have the money, I would just get a lightweight blanket even though your yearling doesn't have shelter.  The blanket will protect against cold wind and rain (and snow!) but it won't cause her to rely on it.  I wouldn't leave it on her all the time, either, because if you're not going to clip her you don't want her to learn to rely on the blanket for protection.  I would only put it on when the temperatures go below 0, when it's snowing pretty hard (not just a few flakes), when there's a cold rain, or when there's a cold wind.  Horses have the ability to deal with temperatures up to 0 degrees Farenheit and snow.  It's the temperatures below 0 and the cold rain and wind that really causes them to lose body heat--fast.

When I lived in Alaska I never blanketed my quarter-pony mare, even when it was 20 below. But she also had a stall she could walk into from her paddock, and the stall was part of a 30-horse stable. If we ever got wind or snow she could go in, but there were plenty of days when I'd find her with a crust of snow on her THICK, THICK coat in the morning: she'd stayed out in the snowfall overnight without coming in to get out of it. Apparently, she could deal with it easily.

when i had my yearling, i had him in a high neck weathabeeta rainsheet, we're south of seattle, it can get cold but he also had a stall at night, but because of the rain i prefered the higher neck...

Hello!  I haven't been to Maryland, but it sounds as if your winters aren't as dramatic as in some places.  Our winters here in West Texas are like that.  We can have very cold snaps that don't last long, then it can warm up considerably.  Since your yearling doesn't have a shelter, I would, as suggested, have something lightweight, for not as cold, but maybe rainy weather; and a midweight blanket for the colder times.  The biggest things your baby needs protection from is wind and rain.  Even with an unclipped coat, a hard rain coupled with a chilly wind, can penetrate the thick winter coat and chill a horse.  If only one blanket is possible, go for the midweight, or a thinsulate blanket.  Make sure it is breathable as well as water and windproof.  I have a thinsulate blanket I bought from SmartPak and love it so much I just ordered another one for my other horse.  They are lightweight and as warm as a medium weight blanket, and breathable in case of a sudden warmup; your yearling won't sweat underneath it.  Also, a sensible price.

I live in WI where it gets pretty cold, not sure how cold it gets there.  I would recommend a lightweight turnout and a stable blanket or blanket liner, that way you can layer according to the weather.  If it gets pretty cold, just using a lightweight won't be enough.  The way the horse's coat keeps them warm is that when it gets cold it stands up and acts as insulation.  If you have a blanket on, that flattens the coat, so you need to replace that insulation with more blankets.  Also, extra hay on cold days warms a horse up as well.