Waterproofs!

Hapless is right. I've just been through the process of buying a new waterproof jacket for wearing outdoors (not golf) and the guy explained that the way in which GoreTex works is based on the temp differnetial between the oustide and the inside.

Because of this he recommended jacket made from eVent material, as you don't have to get the inside temp as high for it to work properly, so it is good for hiking etc, and is probably good for golf. I'm suprised no manufaccturers have went with event over Goretex for this reason.

Apparently the only downside is that it isn't as durable\strong.
 
I bought a new Galvin Green Angus jacket and was very dissapointed in it and sold it on. Admittedly I didn't try it in heavy rain but being an ex-Rugby player I can tell you these jackets are intended for the slimmer non-pie eating build! The material wasn't as flexible as I thought it would have been either and made a fair bit of noise when swinging. I also found it odd that there were no pockets in the jacket.

I've now got Pro-Quip silk touch and Ping collection suits which I've tried in very heavy rain and they both perform admirably.
 
Top