You can set your iPhone to give you notifications if precipitation like rain or snow is on the way where you live, but you must be running iOS 15 software.
On Nov. 23, 2021, the British viral news site Unilad published an eyeball-grabbing headline, "Your iPhone Has A Hidden Setting That Will Tell You When It’s About To Snow."
The article referenced a new feature in the Weather app included in the latest major iPhone update. So while it's true that Apple has a new feature sending you notifications in the event of precipitation, you have to have downloaded iOS 15, which is Apple's software update released in September 2021.
In order to receive the notifications, iPhone users have to enable them in their phones' settings. Here is how the technology news site CNET described how to turn on the notifications:
Once you're running iOS 15, you can turn on the new precipitation alerts by opening the Weather app, then tapping the three-line icon in the bottom right corner of the screen. Next, tap the circle icon with the three dots in the top right corner of the screen followed by Notifications.
Slide the switch next to My Location to the On position and then tap Done. If you have more cities added to the Weather app, you can turn on alerts for each one.
“Check the Weather on IPhone.” Apple Support, https://support.apple.com/guide/iphone/check-the-weather-iph1ac0b35f/15.0/ios/15.0. Accessed 23 Nov. 2021.
Cipriani, Jason. “IOS 15 Hidden Features and Tricks You Didn’t Know Your IPhone Could Do.” CNET, 22 November 2021, https://www.cnet.com/tech/mobile/ios-15-hidden-features-and-tricks-you-didnt-know-your-iphone-could-do/.