Forecast: today Partly cloudy in the morning and breezy until afternoon. / tomorrow Partly cloudy until afternoon. / day after tomorrow Clear throughout the day.
For that, they pulled in JQuery and made a XMLHTTP request.
If their intent is to lower energy consumption of their server alone, offloading this weather check is the correct choice. But surely requesting+caching that info on their end (by perhaps rebuilding the static site every hour with an updated forecast) would be overall more efficient than having X number of clients request the data.
Surely rebuilding the website every hour (and invalidating the cache for X number of clients) would result in more requests.