Cold Water: A Temperature Guide – Outdoor Swimming Society Outdoor Swimming Society

Cold water temperature varies hugely, and while this isn't scientific, anecdotally, open water swimmers experience it in these bands.

Cold water swimming: a guide to temperature - Outdoor Swimmer Magazine

Winter swimming - Wikipedia

How to acclimatise – Outdoor Swimming Society Outdoor Swimming Society

I survived the cult of cold water - The Boston Globe

Polar bear plunge on New Year's Day? The science on cold water dips is mixed : Shots - Health News : NPR

Guide to safe cold water swimming – Williamstown Open Water Swim Coaching

What Happens to the Body in Cold Water — WILD SWIMMING CORNWALL

Cold-water swimming: What are the real risks and health benefits?

What's the temperature 'sweet spot' for swimming in lakes and rivers? - The Weather Network