Cumulus Support

Will someone please explain why cumulus has been showing a cloud base of 2517 ft when there isn't a cloud to be seen? I know that there is a formula to get this figure, but with the pressure showing 1040.7 at the moment, shouldn't cumulus know there is no clouds, the symbol on the weather station has been showing a sun for the best part of 36 hours now.
My station is 700ft above sea level, with the relative pressure adjusted accordingly, in case this makes some difference.
Will my adjusting the pressure extremes in the setup have something to do with it
I realise the program has its limitations, I just wondered thats all.

shouldn't cumulus know there is no clouds

Sadly, Cumulus has no way of knowing whether there are actually any clouds or not, your weather station doesn't supply it with that information.

It uses a very simple calculation. It assumes that clouds form when the air reaches saturation. It assumes that the dew point difference falls by 4.4 degrees F per 1000 ft of altitude. When the dew point difference reaches zero, that's your cloud base.

The beteljuices note on CBH figure:

"NB, This is the theoretical LOWEST height that cloud COULD form
Above Ground (sensor) Level - any cloud could be higher or
it could be clear ! "