The Melville Water reading is take from a pylong half way between Point Majestic & Pelican Point. Swanbourne is near the rifle range.
Can't say I've seen Melville & Swannie giving
opposite wind directions? Maybe in summer when it's still easterly at the river when a SW seabreeze is in at the coast? .. Melville is generally lots less than the ocean because the wind gets reduced by land effects such as hills and tree's.
Enjoy .. Laurie