They're fine in most NZ temps. They can loose a lot of suppleness in cold weather, but are still usable. To improve their performance on a cold winters day store the reel in a hotwater cupboard overnight before you go fishing. Dashboard of your car with heater turned on works well too.

Seawater temps are usually in your favour. Leaving the reel outside on a cold winters morning is the killer. Similarly, I wouldn't use them in freshwater in wintertime. Winter freshwater temps are too cold.