https://porchweather.com/ - free app for notifying you when the weather is right for opening your windows. The idea is to save you a few bucks on using air conditioning as well as simply enjoying some fresh air.

Tracks temp, humidity, wind speed, and precip chance and you set the parameters.

Notifications are currently email and web push. SMS is too expensive to run as a free service. I think the next direction is probably an app, as web push support in iOS is not great.