Size for wood rails for fence

[ss]

Would 3" x 1" inch rails be sufficient for a fence. Or should I use 3 x 2 inch? Vertical slats with a slight gap between the slats. Max height 6 feet. Posts 6 feet apart. thanks

[Bob Minchin]

ex 3" arris rails would be stiffer and the conventional approach. Self draining too

[harry]

It depends on the purpose of the fence. If it is ornamental, it can be as light as you like. If it is to keep something/one in/out, it needs to be stronger.

Also depends on how windy it is.

[Rick Hughes]

I used 4x2 cross rails with4 x 1 slats, aprox 1" between each slat, and another row behind cross rail ...staggered

[ss]

Just to improve privacy, I have a hedge at the back of the fence but foliage disappears in Winter, and a road beyond that. Wind factor normally is ok except when we get any storms (Scotland). Crime rate low so I dont expect intruders.