Buyers fly rod weight guide for NZ conditions;
A lot of NZ's fly fishing is on smaller to medium waterways where fish can be spotted. Size of fish and the often windy conditions mean that rods in the below ranges are most suitable.
4 Weight fly rods These are for the expert who likes to fish very light gear in smaller streams with floating lines and small dries and nymphs. The dry fly purist will love this weight rod!
5 Weight fly rods: Are the choice for experienced fly casters, and are the choice of many as their prefered weight. Best used on smaller to medium waterways for delicate presentations of dry flies and nymphs with floating lines. It's more versatile than the 4 weight and will handle larger fish and cope with more wind when in the hands of an experienced fly caster
6 Weight fly rods: This is my pick as good general all round weight rod for New Zealand conditions. Good in small to medium waterways and lake edges, while also allowing you to be successful on larger waterways. A #6 weight will have enough back bone to fight big fish, cast into moderate winds, yet still be able to present a fly delicately to a wary fish. Line choices can also make a big difference, so match them to where you will be fishing. Presentation type lines are good for dry flies and smaller nymphs. The general purpose line as the name suggests is the all-rounder and are the most popular choice. While a backcountry type line will help if you fish in those places as they can handle more wind and cast larger flies more easily. The #6 weight rod is also heavy enough for fishing sinking lines with lures etc.
A #6 should be the learners choice as it'll cover the general fishing experiences they are likely to encounter
7 Weight fly rods: Heavy enough to cope with wind, is ideal for medium to larger size rivers and lake fishing where distance becomes more important. It's getting a little heavy for delicate presentations, but with more distance you be reach those fish on the 'other side' and take on the infamous Nor Wester. It's also a good weight for fishing larger dries, heavier nymphs and lures with sinking lines.
8 Weight fly rods: Lakes and larger rivers where more distance is required and presentations don't need to be so subtle. Ideal on rivers such as the Tongariro where it'll help cast the heavy nymphs or wet lines that are used.
9 Weight fly rods: These are for a more specialized use, in heavier condition; Lakes, larger rivers, saltwater, distance casting and even salmon fishing.