I just had to share this with you, I found it on the BSAC website:

Winter Diving
If I have a favorite time of year to go diving it has to be in the early part of spring as new life is just starting to get going. However, a very close second is winter diving, especially in Scotland.

There is little to match a crisp February or March day with a sharp frost, or even snow on the ground, for clearing away the cobwebs and giving you that good to be alive feeling. The anticipation of entering the mirror calm but apparently black water is tempered by an expectation of the chill it will offer, only to be rewarded by the relative warmth of the water and the sheer enjoyment of being in this unique environment that few people get to see. The only difficult bit is the reluctance to leave the water for the cold of the surface and getting changed. But the final reward of a post dive drink beside a roaring fire in the local hostelry and the smug satisfaction of a rewarding day’s activity put the final icing on the cake.

Jim Watson (BSAC Safety & Development manager)

It reminds me of when I was learning to dive – we were down at Horsea Island in Portsmouth doing our early sheltered water dives – in January I remember it was hard to get out of bed because I knew how freezing it was outside, but I did get out of bed – and I was first in the water. It was freezing cold, but boy I felt great when I was out and dressed again.