I'm using the Core Reporting API (Reporting API V4).
Is there any way for me to determine the last time the data my query is returning was updated?
I'd like to be able to indicate whether the data being displayed was last updated several hours ago versus several minutes ago.
The API does respond with isDataGolden
which tells you if the data will change again, if your website is small the data processing latency could be almost nothing.
From your question it sounds like you are more interested in not just if the data is stale but how stale. You could request the the ga:hour
and ga:minute
to find out when the last processed hit was recorded.
Note there is also the Realtime API which gives you a read of what is happening instantaneously.