Hi
For anyone using a weatherstation with Wunderground.
I have written a set of spreadsheets for data analysis in Excel.
Currently these allow detailed visualisation by day, month, summer, winter, year. Year on year, month on month season on season comparison etc.
I have 2+ years of data from my site ILLAND3 (using Youshiko YC9390 but this solution is generic) to illustrate capbility
You simply paste the daily stats from wunderground into the sheets (or other data sorce with a bit of manipulation) and the analysis builds itself over time
Available free currently and I will support to the best of my ability.
Email me if you're interested.
Steve