If you ask Siri about the weather on your iPhone now, you'll get information from the standard iOS weather app – even if you have other weather apps installed and you prefer them. But that does not have to be the case. With Siri Shortcuts in iOS 12 and later, you can set specific phrases that Siri will respond to for any compatible weather app you want.
Third-party compatible weather apps that work with Siri include Carrot Weather, Dark Sky, The Weather Channel, Weather Gods, and MyWeather. It is likely that more will follow, so if you do not see yours here, please be patient or contact the developers to find out when they want to implement Siri Shortcuts.
Each app supports Siri Shortcuts in their own way, as you set a phrase to which Siri is to respond will be different. With an app, you can set Siri shortcut phrases directly in the app, or simply link them to Siri Suggestions in Apple's Stock App. It may also be easier to set Siri shortcut phrases for your favorite weather app using the Apple Shortcuts app, which is a bit more complicated than the other methods.
An example of an app that lets you create Siri shortcuts directly from within is Carrot Weather. Therefore, we use this app as an example of this method. Other weather apps that provide this capability work similarly.
To start, open Carrot Weather, tap the arrow in the upper-right corner, and then tap Settings. Next, select "Siri Shortcuts" and you will see the available options. This app has a link to show the current weather, advanced forecast, rain report, or other interactions. There are also other data points that you can use in the Shortcuts app for more specific actions.
To keep things simple, select "Current Weather" from the list. Here you can specify a custom phrase to link to Siri. At the bottom, tap on "Type Phrase".
After selecting and typing your phrase, either tap Done. You will see that "Current Weather" on the Siri Shortcuts screen is now lit blue to indicate that the shortcut is set up, and your Siri Shortcuts phrase will be displayed. All that's left is to try out your new shortcut!
For some apps, the Siri shortcut options are not directly integrated with the in-app settings. If not, they probably use the Shortcuts API via Siri Suggestions in Apple's Stock App or notifications on the lock screen.
The trick is that these suggestions are not necessarily displayed for your weather, unless you do so frequently. However, if you already use the app for your weather needs, this is probably not a problem.
I've never seen suggestions for a weather app lock screen. Instead, open the settings and tap Siri & Search. "You may be able to set a short cut option in Suggested Shortcuts for example," See Forecast "in the picture below for The Weather Channel App. Your intended shortcut may appear here if you have just used that app
However, if you do not see what you want to see there, tap "All shortcuts" to find one, if you do not have it, you probably have not triggered it yet by using the app properly, dive then enter the app and try again.
When you tap the shortcut you want, tap "Type." On the next screen, type in your custom phrase to recognize Siri. to confirm the link.