A tip for anyone else attempting to do an initial install of a Davis WeatherLinkIP, to change from DHCP to a Static IP Address and other changes you may desire from a Mac:
PROBLEM: I successfully found the randomly assigned IP of my new WeatherLinkIP, and the built-in HTML page appeared using the latest macOS 10.12.2 and Safari 10.0.2. But, changing any of the parameters and selecting save on the interface, resulted in the original default screen returning with no changes being made.
WORKAROUND: Use Chrome to do the same process. Perhaps Firefox would work as well - I didn't try it. It appears the built-in Davis HTML page has some incompatibility with the latest level of Safari. Fortunately, once the changes are made, I won't need to do it again.