EtherSIA addresses former lack of IPv6
I looked into online weather, and saw weeWX. (I did not investigate other software because weeWX met so many goals that I generally like; as relatively niche software, I expect it doesn't have much competition.
Grafana, probably graphite, probably collectd
An alternate approach would have been to use Plugin:cURL instead of Plugin:Exec, following these directions. I wrote my own script for Exec so that I could verify that the temperature reading was valid before reporting a value.