The first chill is in the air in most places in the northern hemisphere, and you're probably getting your horses ready for winter. Whether that means stocking up on hay or reseeding pastures for spring growth, winter chores are on the way.
Take your blankets out of storage and give them a thorough examination. Repair broken straps, stitch up tears, and wash them thoroughly. If you plan to clip your horse for winter work, he will definitely need blanketing. It's a good idea to have at least two weights of blankets for clipped horses; one lighter, daytime blanket and one heavy blanket for cooler temperatures. On super cold nights you can layer them.
Remember though, that horses in the wild don't have blankets, and most survive the winter just fine. Indeed, most healthy horses that aren't in winter work probably don't need blanketing at all if they have a good place to take shelter from the weather-particularly the wind. Older horses, ill horses, or horses that may be prone to dropping more weight than usual in the winter probably need blankets.
If you do choose to blanket your horse, remember that an overheated horse is more prone to getting sick. Just as you strip your sweaty clothes off after a winter workout so you don't get a chill, horses can get a chill if they're over-blanketed and overheat in the cold.
The lesson is to under-blanket rather than over-blanket. Take your climate into consideration, as well. If you live in a place where it tends to be sunny but cold during the day, consider removing the horse's blanket in the morning so he can gather some winter sun warmth in his coat. Put the blanket back on when it gets cold after sundown. If you live in an area where there is a great deal of precipitation, buy the best weatherproof blanket you can find, and have an alternate available in case your horse's blanket soaks through.
Also, blanketing is a commitment. Once you start blanketing your horse, you need to maintain the routine because his coat won't grow as deep if he's blanketed.
It helps to set a temperature below which your horse will be blanketed. That temperature depends on your climate and preferences.
Here are a few tips for deciding on a blanket:
1) How does it fit? An ill-fitting blanket will cause rubs on the horse's withers and shoulders.
2) Is it the right weight? The rule of thumb is: Use a mid-weight blanket for 32 degrees. Use a heavyweight for 20 degrees and colder.
3) Is it the right fabric? Stable blankets tend not to be weather proof, and as their name says, they tend to be used for horses living inside. Some blankets are water resistant, but not necessarily waterproof.
4) When in doubt, consult an expert. Blanket companies have resources to help you decide what blanket best suits your horse's needs.