Timeline graph for Stream Analytics for the past one hour

Currently, you should be able to use Q&A to accomplish this. Can you try the following steps:

1. Go to the dashboard in question

2. In the Q&A box, type "[value field] by [time feld] last one hour" - e.g. "temperature by time last one hour"

3. Once you're satisfied with the visual produced by Q&A, press "pin visual" in the top right

4. The visual will now be pinned to the dashboard, and will update in real-time

Longer term, we're doing work to allow Azure Stream Analytics to output to the recently released streaming datasets. Streaming tiles, which are built atop streaming datasets, have native support for displaying data over a set time window. Look out for private preview of this sometime before the end of the year.