An excerpt from Fly-Casting Finesse, by John Field
If wind is blowing onto the same side as your line hand, it’s not much of a problem. It will probably suffice to use additional line speed to prevent wind drift on your line and fly to maintain distance and accuracy. Wind is on your casting shoulder is a potential hazard because the fly and line can hit you. If the wind is light, maybe 5 mph, additional line speed will again help. If it’s puffing 5-10 mph, I recommend a fast, low side-arm stroke. This will separate you and the hook by almost a rod length and if the loop is a little wobbly on the backcast, it’ll hit the water, instead of a person or the boat. When it’s blowing 10-15 mph, I recommend the Off-Shoulder and Cross-Body Cast. If it’s blowing 15-25 mph, I recommend the Barnegat Bay cast for safety and comfort. At least the wind will be at your back! Another way to deal with wind on your casting side is to use your non-dominant hand. Remember, wind is seldom constant, use any break between gusts or favorable change in angle, to make a better cast.
To make the right-handed Off-Shoulder Cast, angle the casting plane to the left overhead by lifting the elbow, with the casting hand stopping above the right ear. This places the rod tip and path of the line and fly, downwind, out past the left shoulder. Move the line hand outward so the line is not in your face. You will be looking through the opening between the line and the rod like looking through a window. The Cross Body Cast operates on a similar principle but the stroke arc is either in front of the chest, or outboard of the left shoulder if you need to make a longer stroke. This cast requires extension and retraction of the arm to keep the rod tracking straight. That covers two of the four wind directions. Casting with a tailwind and into a headwind are still ahead.
When you’re casting with a tailwind, or downwind and the wind is at your back, it will help carry your forward cast but unfortunately the wind will put the brakes on your backcast. Angle your backcast downward to reduce lift and angle the forward correspondingly upward. The wind will help carry and open the forward cast. False casting with the wind can cause excessive line speed like a bullwhip and overly abrupt stops. It should be done with reduced stroke and hauling effort to prevent problems.
If you’re casting into a headwind, direct your forward cast as close to the water as possible and direct your backcast on an upward trajectory 180 degrees away from the forward cast. Presenting close to the surface prevents excessive wind drift. In addition, when casting against the wind, use adequate line speed by making a harder stroke and, or, a faster double haul. A headwind will have an affect on backcast timing because loops open faster down wind, but may stay aloft longer due to wind drag. Remember, shooting line downwind in a false cast might overload the rod when casting in the other direction into the headwind. This will cause a wide loop and lost line speed. Also, refrain from shooting too much line into the backcast against the wind or it can stall.
When the wind is howling and you’re wading in the open, try using very low sidearm casts with a downwind delivery. By casting as close to the water as possible without touching it with the fly or line, you take advantage of four things. First, by reducing casting angle, you are reducing the frontal area of the line. Second, there is a slight difference in the wind speed closer to the surface of the water than higher above. This wind speed gradient was featured in Larry Pratt’s article, Under the Wind, in the Spring 2001 issue of The Loop. The third thing is, the wind will assist in loop and leader turnover. Even if you don’t get good backcast turnover, the force of the wind will straighten that forward cast right out! And lastly, the sidearm position almost assures the fly will not snag you. If the wind is blowing downstream, consider a downstream presentation. If it's upstream, consider an upstream presentation. Does that suggest to always pick a downwind cast when the wind is howling? Maybe so. I also recently learned a new wind cast from my newest island friend.
At the Fly Fishing Show in Marlborough in 2013, I was trying to make a connection with Tourism Bahamas for my Flats Prep School, when I met Prescott Smith, owner of Stafford Creek Lodge, Andros Island, Bahamas. He is a great guide and son of Charlie Smith, originator of the Crazy Charlie. When I told him I prepare northern anglers for the ravages of the windy flats, he told me he developed a technique he calls Taming the Wind. He even put out a DVD about it. He told me the way most people cast in wind is wrong. He shuns tight loops when casting into the wind because he says stopping the rod makes the line more susceptible to the wind.
We went to the casting pool, without any wind and he demonstrated his technique. Prescott makes an overhead cast with an oval stroke without stopping the rod or the line. He uses a medium size loop with constant tension until the delivery stop. After the stop, he quickly lowers his rod tip and elevates the rod butt by raising his elbow. This anchors the line in the rod leg of the line in the water to prevent wind drift. This technique does not let the line slow enough for gravity or wind to really affect the cast. Prescott's favorite way to deal with wind on his casting side is the “over the opposite shoulder cast.” For most people the Taming the Wind Cast is limited to a maximum of about a sixty feet, but on a really windy day, many anglers will take that!
The finish of Prescott’s cast reminded me of Chris Korich’s laydown in ACA fly accuracy on a windy day. Chris says it’s like the anchored line is a railroad track to the target. I know casters have been doing that trick for decades. A fishing cast was recently developed in parallel by a Florida angler named Joe Mulson and named after him as the Mulson Wind Cast. It can be described as a high-speed cast with a tight-looped cast with a down mend. The loop looks like the outline of a boat hull. Once the line touches, the wind has no affect over that portion and the energy transfer down the line until it straightens. In Montana, they have a similar cast they call the Madison cast, useful for casting in its notorious winds. Practice these casts under actual wind conditions at home, before testing them on the flats.