After thinking I had somehow escaped the dreaded wind spike curse with these units, over the last few days I have been getting gust speeds of 92 km/h. So the only option is to replace the cabling I guess.
There is a lot of information on here about replacing the cable with shielded twisted pair Cat5. Does anyone know if it must be shielded cable? Standard Cat5 is a lot easier to find and it is also cheaper.
Try looking at this topic: Davis Weather Stations V.S. LaCrosse Weather Stations .
I know there are quite a few people on the forums that have the LaCrosse (WS23xx) weather station, so they should be able to help you out.
another idea is to just twist lots of times your existing cable… 
The sheilded part is more important than being cat5 or even twisted pair as the signals are all unbalanced, its just that sheilded cat5 is a fairly universal screened cable so it was suggested originally… I actually used a 4 core audio screened cable here with total success
As Brian said some people have had success just by twisting the original cable 