Hi Zeppo,
Thanks for reaching out.
I'm afraid that it's not possible to get a weather channel shown all the time. By default, it will go back to display the clock or the photo frame of your choice. However, you can command your Google Nest display to show it. You can use the commands listed on this link.
Since this is a feature that is not yet available, we’d like to take this opportunity to encourage you to send a feedback regarding this and for any features that you’re looking forward to using with our Google Nest devices.
Best,
Princess
