It rains a lot in New Zealand. Some parts get between 6 and 8 metres annually and unlike just about everywhere else I've fished you don't want a wet day, in fact you don't even want an overcast day. What you really want is a bright sunny day, with no cloud and no rain and the best time is mid-morning to early afternoon.
In the high country the wind often appears in the afternoon and makes fish spotting and casting a real problem. Remember these are the spookiest fish on the planet; you'll often get one cast and you absolutely must see them first.
Friday: two anglers, constant rain, 6 miles on a climbing, scrambling, boulder hopping river. Spotted six, spooked one, landed three. Two pounds (where did he come from?), four and a half (pictured), five pounds.
One of the fish we didn't catch was a double... it could have been a great day (especially since I was on strike).