When salmon fishing, always take a thermometer with you!
It is well documented that as a river warms up, salmon respond to smaller and smaller flies. Several tables have been published giving hook size v temperature. Here is the Salmon Atlas online version that also allows river conditions to be taken into account. Use this calculator to give you an idea of what size of fly you might confidently use. The salmon haven’t read the books, but it is amazing just how small a fly they will take. If a salmon moves to your fly but does not take – change to a smaller fly and try again. It is amazing how often this works!
Note: hook size is given only as an indication – as much depends on how the fly is dressed. The overall length (less tail & eye) is the important detail.
Please take the temperature of the water – and then click the button!