A cron script to compute average/month, ran once per month?

Probably this can be taken further: the cron script would compute the average for last month, and move all previous month rows to “archive” db.

However some people would like to “go back in time” and analyse data: say there is a spike that happened two months ago on a given station. One might want to check the data including “zooming” to see max resolution data to understand the phenomenon better. Then move to other stations nearby to check for the same thing.

I wonder how this scenario could be implemented efficiently.

There is one row/device/minute added to the db constantly.