Vixen
Senior Member
Looks like it is the other way around and good to know the upside down Cat 5 is less intense. Plucked this from the BOM website.
View attachment 141394
It's more to do with how the US calculates mean windspeed. It is averaged over 1 min where Aust is averaged over 10 mins ( I think that's right anyway). Cat 5 is scarey whichever way it's done
Anyway I really prefer to use this system of categorising