Nobody knows what features and widgets may or may not get added to any watches in the future. Garmin doesn't usually announce anything ahead of time.
Occasionally, Garmin will confirm that a new feature on a new watch will also trickle down to some other existing watches, but to my knowledge they have not made any mention of any weather widget.
Note: There is currently, and always has been, a weather widget on the Fenix 6. I've never seen whatever weather widget is on the 945LTE, so I have no idea if it's exactly the same, or totally different, or what.
