What Weight Fly Rod for Trout? A Complete Guide

What weight fly rod for trout feature image

Choosing the right weight fly rod for trout depends on three things: the type of water you will be fishing, the size of fish you will be targeting and the size of flies you’ll be throwing when you are fly fishing.

In this article, we will look at each of these in turn and help you make a decision between a 2 or 3 weight outfit or a 6 weight fly rod for your trout fishing.

Having the right fly rod or fly rods for the situations you are encountering on the water will make you a more successful angler.

The ideal fly rod weight for trout

Before we consider these factors, it is worth going over the numbering system that determines the “weight” of a fly rod.

Fly rod weights go from 1 weight fly rods for the tiniest of trout streams right through to 14 weight beasts for tackling GTs and other giants of the saltwater.

For trout, we are really looking at fly rods in the 2 weight to 6 weight range ranging between 7 feet and 10 feet in length.

The “weight” of the fly rod of course is not a measure of its mass – rather it is the weight of the line that it is best suited to in terms of a pairing. The heavier the line weight, the more load it puts on the rod and manufacturers rate their rods in this way.

See also:

Choosing a fly rod action for trout fishing

Before we look at fly rod weights, we are going to briefly touch on rod action. A modern fly rod’s action ranges from slow to moderate/medium to fast.

The way this rating works is when load is applied to the fly rod, such as when you pick up line from the water to cast, different fly rods will behave differently

  • A fast action fly rod will flex predominantly at the tip and remain stiffer. It will generate a higher line speed and longer casts for an experienced angler, and will cope with high winds, but is less forgiving for the beginner
  • A moderate action fly rod will flex lower in the fly rod and will reward a slower casting stroke. These fly rods can land a dry fly with more finesse than a fast action rod and are more forgiven both in terms of casting defects and also in playing fish
  • Slow action fly rods, which are not common these days, are another step in this direction suiting a languid casting style and being known for landing a fly very subtly. But these fly rods will struggle in windy conditions and situations where you need to punch out a tight fast loop

Choosing a trout fly rod weight based on the type of water

This is probably the simplest way to approach the question of what size fly rod you need for trout.

Think about where you fish for trout most often, or where you plan to fish for trout.

Is it a small, heavily forested stream where the average cast is maybe 10 feet?

Do you like indicator nymphing in a moderate freestone river? Or casting small dry flies in a spring creek?

Or is a big tailrace where you are going to be swinging streamers and trying to cover as much water as you can?

These two situations will require vastly different fly rods.

We’ve summarised some typical rod weights, lengths and actions of fly rods for various types of water

Ideal Fly Rod Weight: A Simple Chart

SituationIdeal Fly Rod WeightIdeal Fly Rod ActionIdeal Fly Rod Length
Small streams with heavy tree and shrub cover2 to 4 weight rodsModerate action7-8 feet
Typical freestone rivers – dry fly and nymph fishing5-6 weight rodsModerate-fast to fast action 9 feet
Tailraces and large freestone rivers, streamer fishing6 weight rodsFast action9-10 feet
Lakes (and windy areas)6 weight rodsModerate-fast to fast action9-10 feet

Choosing a fly rod weight based on size of trout

Generally, but not always, the size of the water is reflected in the size of the trout – ie small streams tend to hold smaller fish and require shorter casts of more precision.

But it doesn’t always hold true. In New Zealand and in some really productive spring creeks in the US, you can get big trout of 6lb and above in very small creeks and choosing a fly rod weight has to take into account the strength of these fish.

If that’s the case in the water you like to fish, choose a rod at the upper of the recommended weight for that type of water. For example, you might choose of a four or five weight fly rod instead of the three weight if you expect to encounter some big fish that need stopping before they get into, for example, an undercut bank.

Choosing a fly rod weight based on the size of the flies

The other key consideration is the size of the flies you are throwing. As we discussed, the loading the rod is subjected to is governed by the weight of the line and not the fly in fly fishing (unlike lure fishing where the reverse is true).

However, big and bulky flies sometimes require us to rethink things. For example, a two or three weight medium action rod is going to be fine to cast delicate dry flies in #14 and #16, but it will less effective throwing a big tungsten beaded nymphs or streamers (due to the weight and bulk) or a big deer hair terrestrial (due to the air resistance) if that’s the kind of fly fishing you like to do.

Again, it is worth going up a fly rod weight or two if these kinds of flies are a regular in your fly fishing arsenal. In these circumstances a six weight might be the best fly rod for you.

Typically, these kinds of flies attract – on average – larger trout so this aligns with the section above really.

Fly Rods for Trout Fishing: Weight and Wind

The other thing to think about is how windy it is when you fish. Four weight rods and below, particularly those with a moderate action, don’t handle strong wind well.

A 5 weight fly rod is better, but a windy situation means a six weight fast action rod with plenty of backbone will be the best fly rod to use. In really wind areas – such as Patagonia or New Zealand – anglers will overline this rod (use a fly line weight one or two levels above the rod’s rating) and even use seven weight fly rods to deal with howling winds.

Fly Rods For Trout Fishing: Length

The final thing to consider is the length of the rod and what is appropriate for the type of fly fishing you do.

As a general rule:

Shorter length rods

  • Are good for casting in tight conditions where trees of other obstacles can impede a back cast
  • Aren’t good for mending line in tricky currents as you have limited reach

Longer length rods

  • Are good for fighting fish and mending line in tricky currents
  • Aren’t good for forested streams and rivers

In general, the lower the fly rod weight the shorter the fly rod, with some exceptions for specialist rods for such euro nymphing sticks.

As you can see from the table above, in a three or four weight fly rods are typically 7-8 feet long and five and six weight 8.5 to 9 feet. Once you get to a six weight fly rod and beyond, you have the option of going to a 10 foot rod, which can be the best fly rod choice for lakes, particularly for float tubing, but also for shore fishing.

What fly rods do I use for trout?

brown trout fishing tasmania lakes Rick Wallace Greg French
My preferred river set up – a Sage XP with an Air Flo Super Dry Elite line

My own set up for trout fly rods is:

  • A 9 foot five weight Sage XP spooled with a six weight Airflo Elite line (I do a lot of small river fishing with this)
  • A 10 foot six weight Sage XP spooled with a six weight Scientific Anglers Anadronymph line for lake fishing. This fly rod set up casts like a cannon and I like the extra length when fighting a fish.

The one rod I will add to my trout fly fishing arsenal is an 7-8 foot three weight fly rod for small, enclosed streams of which there is quite a few close to me. In these waters even a five weight, particularly a faster action rod such as the XP, feels like overkill and the 9 foot length is too long.

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Rick Wallace is a passionate angler and fly fisher whose work has appeared in fishing publications including FlyLife. He's appeared in fishing movies, founded a successful fishing site and spends every spare moment on the water. He's into kayak fishing, ultralight lure fishing and pretty much any other kind of fishing out there.
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