It starts on December 2nd and goes until December 8th. If you know someone who's grieving, now is a good time to check in on them. Even if it feels awkward, it's generally appreciated, though everyone is different.

You can see more at https://www.samhsa.gov/newsroom/observances/national-grief-awareness-week

Here are a few of the images from that page:

Here's more information from the organization that organizes it:

https://www.thegoodgrieftrust.org/ngaw/

Also, the 5 stages of grief model is outdated and should not be used:

https://en.wikipedia.org/wiki/Five_stages_of_grief#Criticism