It can be a bit of a mine field choosing your first fly fishing rod & line. Fly fishing lines are numbered according to their weight, the higher the number the heavier the line. Rods are also numbered, you should match the number on the rod to the number on the line.
This standardisation is known as the AFTM (Association of Fishing Tackle Manufactures) rating. For example a rod that is AFTM #6 is designed to cast a 6 weight line. A rod that is AFTM #3 – 4 will cast a 3 or a 4 weight line.
There are lots of considerations when choosing a fly rod weight, here a 4 important ones:
1. The size of fish you might catch
When fly fishing we could be targeting small wild brown trout through to huge salmon or pike. The bigger the fish you hook, the stouter rod required to handle it. A stouter rod will naturally require a heavier line.
2. The size of fly you are trying to cast
Trout flies range from a few millimeters through to several inches, flies for other species such as pike can be even bigger. The larger the fly you are trying to cast, the heavier the line needs to be.
If you need to cast distance for clearing weed beds or shallows or to reach fish at extreme range then you should opt for a heavier line weight probably 7 or more. The lighter end of the weights 2,3,4’s are just not sufficient for generating the line speed required for long range casting
If you are fishing in a windy location then you need to consider your line weight carefully. Even if you are fishing for small fish with small flies windy conditions require a heavier line rating to punch through the breeze.