I also always plan on wearing a full suit (that is a personal preference of mine). A full suit protects me from stings and urchins and sun exposure, while also providing the most insulation. I know a lot of people like to dive in warm waters in just their bathing suit, but keep in mind your body temperature is about 98 degrees. Any water below that will cool you down and eventually cause a chill (or more dramatically, warm water hypothermia).
If you want to stay in for a long time, prepare to be covered. Here is a basic guide to follow:
If the water temperature will be 80 degrees or higher, you can plan on wearing a 1mm to a 2mm shorty or full suit. (Some of you hotter folks might even go commando). This covers most of the islands in the Caribbean, which are quite warm and pleasant in the summertime. Although on average temperatures are warm, pack layers in case of thermoclines or deep dives.
If the water temperature is 73-79 degrees, consider a 3mm full suit to a 5mm full suit. This includes a lot of the east coast of the US, the islands of Hawaii, and of course the Sunshine state of Florida, known for it’s multitude of wrecks to visit, and the famous Christ of the Abyss.
For 66 degrees to 72 degrees: a 5mm full suit to a 7 mm full suit is necessary to retain body warmth. You should consider packing extra layers like a vest, hood, and gloves. If your destination is Southern California (my home base and favorite place to dive) we consider these temperatures our warmer Summer temps and some of us are prone to wear our lighter suits, but i always stick to a 7mm to fully enjoy my kelp forest. Occasionally you’ll see me sans hood in the hotter months of July and August, but always in a full 7mm.
If you’re taking a dive trip to water that’s 50 degrees to 65 degrees, I would highly recommend ditching the wetsuit and sticking to a dry suit. This would include all divers headed to Reykjavik, Iceland to dive the pure and clear waters of the Silfra Fissure, or divers headed to British Columbia. I know that only seriously dedicated scuba divers would consider sticking their toes in water this chilly as a vacation, but with the right exposure suit, your efforts will be worth it.
Only you know if you are prone to cold or if you always run hot, but a few minutes of quick research and packing the correct suit will make all the difference in your dive travels this summer.
Authored by: Lindsay Pullin, a SCUBA diving instructor based in Southern California and the owner of The Merbabe Adventures blog.