In response to the incredible interest and thanks to all the feedback in this thread I've added improvements:
* There is now a companion bot Heat Wave USA (npub1h6q…7vf5) which reports only on heatwaves in the US (and gives the temperatures in Fahrenheit)
* The quoted place name includes county and state in the US, and equivalent in other countries
* The posts have hashtags, so you can follow the hashtag for just heatwaves in one country
* There is a link to a map showing the precise location