In this age of dressing casually, down jackets, parkas and bomber jackets are perfectly acceptable forms of outerwear, but if you're wearing a suit, you've got to put on something a little dressier when it's cold or raining. Here is your guide.

Raincoat or topcoat?
Whether you need a topcoat or a raincoat is really a matter of where you live. For those in places that are wet rather than cold, raincoats are likely a better option than topcoats. Raincoats are made of materials that shed and resist moisture, whereas wool topcoats, made of some sort of wool and usually warmer, will take on a musty smell and lose their shape if they are exposed to substantial or frequent rain.

Coat colors
Topcoats are most often produced in black and charcoal, with a smattering of coats offered in camel, olive, and navy. Topcoats don't have to be carefully coordinated with particular clothing. And the reason black and charcoal gray are the top-selling colors for topcoats has almost nothing to do with their color flexibility. It has a lot to do with their ability to hide grime or stains. Lighter colors will show everything, while black and gray won't.

Proper topcoat length
Proper topcoat length is largely a matter of taste. Some men prefer that the coat is long enough that it almost reaches their ankles. Others like a topcoat that hits not terribly far past the knee. Neither of these is necessarily wrong. Still, a good rule of thumb is that the topcoat should be long enough that it hits almost midway between these two extremes. This will offer both warmth and protection to most of the clothes as well as the wearer.

How to select topcoat size
It used to be that you selected a topcoat one full size larger than your suit size, for ease over the extra bulk of a suit coat - for example, a man sized 42 regular would wear a 44 regular in topcoats and raincoats. In recent years, however, many manufacturers have begun to accommodate the clothing typically worn underneath the outerwear. This means that, as often as not, the proper size of topcoat is the same size as your suit size.

It's simple
So really, the choices are pretty simple the next time you're suited up and heading into cold or rainy weather. Topcoats and raincoats not only keep you warm and dry, but they ensure that you'll arrive at your destination looking sharp and presentable