Legacy Cumulus 1 release 1.9.4 (build 1099) - 28 November 2014
(a patch is available for 1.9.4 build 1099 that extends the date range of drop-down menus to 2030)
Download the Software (Cumulus MX / Cumulus 1 and other related items) from the Wiki
I think it's time to take the whole thing down and return it to the supplier. It's less than six months old and this sort of thing, along with the problems I've had with the solar readings really isn't acceptable. Time for a wired version.
I called W&S to see what could be done and they're sending me a replacement anemometer and because I've had problems with the solar going off line, a replacement solar unit as well. That's a good result.
You're located not too far from the coast. FO stations tend to fare not so well when situated in coastal areas. Corrosion from salty air seems to be a big problem.
When you get your replacement, see if you can remove the anemometer cups and give the bearings a good coating of protective lubricant. Same for the wind vane.