More aggregated normals

[Strydom]

Hi, thanks for this project!
I hope it keeps running, so here's a suggestion to reduce API load.

I'm running a script to reduce the normals per country region, which requires me to ping the download of normals per station within that country region. I'm reducing the set of station per region just so i don't ping the API so much, but this will likely give a less accurate data set.

I think it would be beneficial to have averages like this already pre-processed, so we don't need to ping the API so much.
I also reduce the regions to a whole country average of the normals.
I doubt I'm the only one doing this, so I assume these aggregations will be of use to others.