Today App still works but it’s not possible to add new cities. This was my goto app for sending screenshots of temperature charts of heatwaves and polar vortices to friends in other countries. https://support.savvyapps.com/article/166-why-is-today-no-longer-in-the-app-store.
The weather app I switched to (last year, I think) is Hello Weather. The UI design is great and the basics of the app are free, but I pay $6.99/yr for the IAP ‘fan club’ unlock, which has real-time radar map layers (precipitation, cloud cover, temperatures, wind, dewpoint, tropical storms), unlocks an Apple Watch app, and, most important to me, lets you choose via pop-up between forecasts from your choice of Dark Sky, Weather Channel, Accuweather, and Aerisweather.
By far my favourite weather app too. Replaced everything else at launch with the exception of Carrot, which I’m forced to keep around Until Hello Weather rolls out the Watch complication I prefer (condition icon + “feels like” temp). They’re working on it though, so hopefully I’ll be able to go all-in on HW later this year!