Hi Pete,
I see your files and you mixed things about "month"

You have data for THIS MONTH, but none for MONTHLY RECORDS!
Double check your records in Cumulus EDIT menu, you have two "month" item
- Monthly records- This month's records
That is why you having errors like Month01TempH in your XAMPP
because your "Monthly Records" page is not initialized!!
You will see in that page that you have to choose records for Temp. Humidity, Rain, Wind...
For all months: January, Febuary, March, April.... a pretty long job... are you sure have do it??
Regards,
Jacques