Lycra skin and/or 3-5 millimeter wet suits are recommended. However, your thermal protection should be based on your individual sensitivity and comfort.
Here is a suggested guide:
|Jan-March||3mm or 5mm full suit|
|April-May||3mm full suit|
|June-Aug||No wet suit required|
|Sept-Oct||1mm - 3mm wet suit|
|November||3mm - 5mm wet suit|
|December||3mm - 5mm full wet suit|