Forecast is updated every hour, and cached offline — the chart always shows current temperature according to last obtained forecast, even when you go for a long run without your phone.
You can unlock professional Dark Sky forecast and all themes via reasonably priced subscription, which covers a cost of data and allows me to further improve Weathergraph.
is also on
Here's my email
*) Dark Sky API will keep on working until the end of 2021, and I wil replace it with one of worthy competitors I am now evaluating.