@BFrança Not that I can see in the documentation. You can drag the slider along but it only adjusts by 60 min increments, and I am guessing that its set this way so that the dashboard isn't bogged down.
I would say Meraki want to keep a fine balance between the devices uploading a useful amount of traffic information vs to much.
If you found this post helpful, please give it Kudos. If my answer solves your problem, please click Accept as Solution so others can benefit from it.