In order to receive the most accurate recording, especially for wind measurements, it’s optimal to mount the station above trees and structures, which means some ladders and climbing is involved. At the very minimum, the unit should be at least 5 feet off the ground, but the higher the better. The National Weather Service actually recommends placing a unit 33 feet in the air.  All this to say, you wouldn’t want to just mount the units flat on your deck railing, but above it. Other things to consider would be the radiant heat that transfers from structures, so finding a spot at least 20 feet away from a structure is optimal. If you are mounting the unit on the roof of your house, you’ll want to think through how.  Instructions recommend placing any sensors on a north-facing wall in a shaded area or at least under an eave. The sensors are weatherproof, but a well-protected area will just improve the readings.