What should the user see if the data are stale or otherwise not available?

[brucecrevensten]

Some cases to consider...

• partially available data
• stale (timeout exceeding (x) hours)
• invalid from some simple heuristic (all NaN or true 0 or null)

Some options... (all would need clear UI explaining the situation)

• Don't display any forecast data at all,
• Display the last known current/forecasts

[jroering]

let's confer with the team and find out.

[dlnash]

The RAND folks might have some good input here - I would say display the last known forecast, with a clear UI message that says it is not the latest forecast.