I filed a bug report. To all people in this thread having similar issues, please do the same.
That will probably increase the chance that MS will take a look at it.
https://flightsimulator.zendesk.com/hc/en-us
In the menu: create request, chose the report a bug option and fill out the form.
We have fixed this issue here by the following simple steps:
1 .The friend in which group you were (or eventually anyone else) must just start a new group and invite you.
2. If you are in the new group, select the “Leave Group” command on the Group icon menu.
After I did leave the group, everything seems to work again as it should. So in the future, until this is fixed, the group leader should not leave the group, until all invited members have left it. This way it seems to work fine. We just played together this evening and followed this rule and everything is still fine.
I hope this will work for you guys also. Good luck.
Thanks. Will try it tonight and report back 
Thanks man!
It worked !
I am still having the same issue even after the new hotfix
This worked thanks!
FIXED MY SAMR ISSUE
It started eversince i joined a group and flew with one of my friends. Must have not exited the group correctly and lockd my weather to a date.
Connect to a friend and leave group or let them join you and leave.
Mine was fixed instantly. Reminder, if you are not leader of group you can not change weather…
See it was posted above. Didnt get to all the replies.
Same issue here. Since the last update I can’t change the weather. And when I try to change the time it is reverted back to the live time. Hopefully it is patched soon.
Have you seen the suggested solution in the comments above?
Worked for me and a few other people.
Doesn’t work. I have no friends on my Xbox, so no way I can be in any party. I disabled online, disabled real life traffic, disabled live weather, changed the time of day (what also doesn’t work anymore). I think it’s just a bug.
I’ve been trying to get the weather presets to work, but whatever preset I pick, I get something else. Several cloud and rain presets result in nothing but snow on the ground. I’m still waiting to get some of those beautiful sun filtered clouds that people have posted in various forums.
I have the same problem with the time and date. I’m stuck on August 4th at 9:32 utc. It is very unpleasant since I have half the planet always at night. I play on xbox series x.
I have tried everything, even reinstalling the game and nothing works
I have the same issues regarding not being able to get “Live Weather”. It was working fine pre last update.
On the front set-up page under :MULTIPLAYER / AIR TRAFFIC / WEATHER and TIME
Only four of these large buttons ( AI / OFF / PRESET / CUSTOM ) are working. Under the pre set WEATHER menu on the same page, live weather will not stay locked in. I have tried adjusting UTC time and all the suggestions above.
Had the same problem, but solved by connecting to another online friend and disconnected propperly then everything was working again
as described above
I also had the same problem as I told above. In the end I have solved it as you said, connecting with a friend and leaving the session correctly. Thanks!!
My date stuck on 26 August. Can’t change date, can’t get rid of live weather. No matter what I do the weather is a mess. I tried it in all modes
Please read the older posts in this thread. The solution is here: Cant change weather - #22 by MonkeyCH
And also this as a follow post: [BUG LOGGED] Unable to leave group, flight options greyed out - Xbox - #19 by MonkeyCH
I have same problem with you have! I can not change weather/time or even server! Whenever I change them, they go back to live mode in seconds!
The solution is in this thread!!!