The wetsuit use for different activities

Short wetsuits

Also known as spring suits or shorties, this style is cut off at the knees and elbows. (Note that "spring" is definitely more Southern California spring than Canadian spring.) The relatively thin material and short arms make for easy paddling. This is great when it's too cold to surf in a swimsuit and rashguard. 

Full suits

Also known as steamers, these are often worn on surf breaks around the world. Full suits are usually thicker and more resistant to flushing than shorties. Usually suitable for summer sessions in the southern Great Lakes or on the east and west coasts of Canada. Worn with a hood, gloves, and boots, many surfers can also wear a 4/3mm full suit during the shoulder season.

Hooded full suits

A full suit with a built-in neoprene hood designed for the coldest conditions a surfer is likely to encounter. Some have an internal fabric lining for added warmth. A 5/4 hooded suit can be used all year round in West Coast spots like Tofino and Atlantic resorts like Lawrencetown, Nova Scotia, as well as the coldest times of the year in the southern Great Lakes. Thicken up in winter on Lake Superior or similar role-shaping extras (e.g. 6/5/4).