A bit of an update. I have calibrated my anemometer, so I'll be able to put that on-line some time, and I have put a sun shield over my external temperature sensor so that it is less prone to direct heating. I have also followed up on Andrew Packer's email and found the La Crosse Weather Station for sale in Australia:
http://www.weatherdownunder.net.au/product_info.php?cPath=32&products_id=76&osCsid=4514a338636bbecb46d35ed72a1d8b2b and another Oregon Scientific one for sale in New Zealand: http://www.monotapu.co.nz/electronics/accessories/weatherproducts/oregonscientific/49226.htm They also seem to crop up from time to time on TradeMe. I have no idea how good these devices are, I am just mentioning them for completeness. Andy
