If this has been requested I apologize, but I am not seeing it.
I did see :
https://forums.cacti.net/viewtopic.php?f=7&t=58387 But I am not sure that request was properly articulated really, as the timezone of the monitored nodes seems more or less irrelevant, but I do have a similar issue as I have users in 5 different timezones (All 4 US zones, as well as BST) I have my pollers all set to Europe/London for timezone but what would be phenomenal is if individual users were able to set their LOCAL timezone in their user profile, then when they view graphs the time is localized to them.
For instance I am in CST so it is 9:25pm currently, my graphs all show 3:25am as the current time as that is the server time on all pollers, as well as the current local time in London. What I am suggesting is that I have the option to select "MY" timezone as CST in my profile, so all displayed graphs and log data are localized to my local time automatically.
This is similar to how splunk, and other tools localize time by user but it is shown in the attached image.
All of my logging being ingested into Splunk is tagged UTC, but my users all have the option to select their timezone which allows the plunk user interface to display the localized time, not the actual timestamp.
If this is not something anyone is working on currently, and there is interest in it I may take a look myself at the level of effort to add it..