7mm vs. 3mm - how much warmer?

[Mike Veitch]

Definitely agree with the hood idea. Beanies are also good in those temps as i find hoods to be extremely annoying.
I never dive without a 7mm, i am a wuss! If you get cold in 78 then i don't think you will overheat in a 7mm. Also, if you are a person who dives a lot, remember that the neoprene will compress, you will get more warmth from a 7mm for longer than a 5mm.

7mm and beanie....perfect!

In fact, i will have a brand new custom fit 5mm and a 7mm at the end of Nov...can't wait. Winter gets down to like 78-79 at times here....brrrrrrrrr.

 

[jbb]

The only way for you to know, exactly, is to try it.

Each one of us has differing thermal characteristics and, as such, each one of us requires different levels of thermal protection.

The matter is extremely subjective.

the K

Absolutely agree, for instance I go tropical diving in 84 degree water with a 3mm full suit and after 3 days of 3 dives per day I start getting cold on the hour long dives. I will be upgrading to a 5mm because of that.

Jason

 

[jakubson]

Absolutely agree, for instance I go tropical diving in 84 degree water with a 3mm full suit and after 3 days of 3 dives per day I start getting cold on the hour long dives. I will be upgrading to a 5mm because of that.

Jason

I wear a 3mm core warmewr under my 3mm fullsuit, and a 3mm beanie. I am never overheated in 84 degree tropical water, but I am a wuss, also. But it sure helps on 5 dives per day when on liveaboards.

 

[Brand0n]

i ware 6.5 wesuit farmer john and a 6.5 wesuit jacket i guesS? im swimming in newfoundland the atlantic ocean with prity cool water all year around and im perfect i find it keeps me warm but not over heated. sorry i dont realy know the water tempertures here but i know its cooler water

 

[HowardE]

I dive a 7mm all winter in Florida with water as cold as 74 for an hour, and don't get cold. As stated before, each person is different... However, in my 7mm suit, I have gaskets by the arms and legs, and I stay relatively dry.

LIL38 as you asked, wearing another suit over it helps... I wear a 3mm farmer john, w/ a 3mm shorty over it sometimes as well, but the 7mm is way warmer for me.

 

[tekdiver170]

Winter time in Hawaii we see temps down to 74 deg. As an instructor who is in the water all the time I have gone to a 7mm w/ no hood and been plenty warm. Most of the time in mid-low 70's a 3mm w/ 3mm hooded vest was great. Less weight on the belt and still able to stay in the water for an hour on cosec dives.

The 7mm jump suit (not farmer john like I wore in Pac NW before investing in a drysuit) was great in the Galapagos w/ 65 deg water - still plenty warm.

Hope this helps.

Chris
Island Divers Hawaii - Oahu, HI

 

[ChrisA]

Can anyone tell me how much warmer I'd be if I break down and buy a 7mm wetsuit? I have a 3mm and it's great for temps above 76 degrees. However, when diving the springs (72 degrees), I can't stay in the water much more than 30 minutes. Would it do any good to wear additional wetsuit or shorty over the top of my 3mm? Or something else under it? (Not sure if that's effective) Looks like I'll be diving the springs enough to have a warmer wetsuit. Don't want to spend the bucks if I won't be much warmer though. Maybe something else I can do? I know wearing a lycra skin underneath does NOTHING to help. Actually, I think it may have made it worse. I'm thinking a 7mm would be good for deep diving too. Drysuit is not an option right now. I already have a small fortune invested (who doesn't?) I know, it's an expensive sport. Help me spend my money wisely

If you use a 7mm suit in 72F water you will be "toasty warm". Maybe even to the point of over heating and needing to flush in some cool water. Our local water temps get down to low 50's and 7mm suits work well enough. Now that the water is mid 60's (at the surface) I'm not comfortable untill I've droped down a few feet and cool off. A 7mm suit is not fun in the parking lot on a hot day but you can bring bottle of cool water to pour down the suit. I assume you are already using gloves, boots and most importently, a hood.

If you don't want to go al the way buy a hooded vest to wear under you 3mm suit. If it is not enough then spring for your 7mm. Here is California I used both a 7mm and hooded vest.

One other thing. a LOT depends on where you are from. I've dived with people from the Great Lakes area who tink 55F is "darn hot" but then these folks are used to hacking through ice to get into the water in Winter. I've also seen Florida divers when they come out here. It takes then a full year to get used to diving in under 70+ water. So when you read the various posts here look to see where they live. The guys up in Canada are likely wondering why you need a wetsuit at all in 70+ water.

a 7mm suit will mean more weight on your belt. I'd bet you will have to double it. Or just less than double it if yu have an AL tank. Suit compression is noticable with a thicker suit. so you will use a bit more air in the BC at depth.

Botton line. You can always unzip the 7mm suit or take the hood off to make th suit cooler but if you go with a 5mm you can't make it warmmer. the 7mm is more versitile

 

[Vtdiver2]

Can anyone tell me how much warmer I'd be if I break down and buy a 7mm wetsuit? I have a 3mm and it's great for temps above 76 degrees. However, when diving the springs (72 degrees), I can't stay in the water much more than 30 minutes. Would it do any good to wear additional wetsuit or shorty over the top of my 3mm? Or something else under it? (Not sure if that's effective) Looks like I'll be diving the springs enough to have a warmer wetsuit. Don't want to spend the bucks if I won't be much warmer though. Maybe something else I can do? I know wearing a lycra skin underneath does NOTHING to help. Actually, I think it may have made it worse. I'm thinking a 7mm would be good for deep diving too. Drysuit is not an option right now. I already have a small fortune invested (who doesn't?) I know, it's an expensive sport. Help me spend my money wisely

I dive in the cold waters of New England, mostly in VT, and use a 7mm. I dive into December and as early as mid March, in temps as low as 34 degrees, basically as soon as the ice is out. I've been known to do up to an hour in those temps.
In mid summer here in Vt the surface temps of Lake Champlain can get into the mid to upper 70's. Yet, get below the thermocline at 30 ft and it drops dramatically, so we still use our 7mm. Trust me, you bake and can't wait to get below the thermocline to cool off. A 7mm will keep you warmer.....question is, will it be too warm?
Chris

 

[ChrisA]

... Lake Champlain can get into the mid to upper 70's. ... Trust me, you bake and can't wait to get below the thermocline to cool off. A 7mm will keep you warmer.....question is, will it be too warm?
Chris

Perfect example of my theory. Here is a Vermonter saying you will "bake" in 70F water. People from Florida would be in totall hypothermic shock at just the thought of 70F.

 

[Mike Veitch]

I agree, when i was freshly out of Canada i dove the waters here 80-84 in a rash vest and shorts...4000 dives later its a 7mm...