You can use openweathermap as your weather source.
You can install this via HPM. Do be sure you can onecall key for open weather api. Many folks have issues because they do not do this and things won't work right
webCoRE also has open weather source integration - ie you can configure webcore with your open weather source data so that you can access it via $weather... in webCoRE.
you can also have webCoRE receive event is data changes in open weather source