Cumulus Support

I want to expand my dayfile.txt with data from a weatherstation nearby it goes to 1950 will this affect running Cumulus and do I have to create seperate month files ?

Cumulus won't work with dates before 1/1/2000, and some parts of it, e.g. "This Year" won't go back before 2003, when Cumulus was born.

But that aside, whether you need the monthly logs depends on what you want Cumulus to do with the data. Basically, anything to do with highs and lows (e.g. most of "This Month/Year/Period") uses dayfile.txt and the rest (e.g. most of select-a-graph) uses the monthly logs.

So I can expand without crashing Cumulus, the only issue is I won't get output in/from Cumulus before 2003, well anyway I can try thanks.