my weather station runs for about 4 years now - and I still wonder about the perfection of data collection

I'd like to generate graphs to visualize the annual min/mean/max values, with an aggregation time of "1 year".
Could you think of an enhancement of the list in the definition of graphs ?
Or would I be able to enhance the aggregation time individual by myself, with a cron job or so?
I would be happy to read about