Start with four pinned daily values. Mon = 5 is the first value, and Thu = 9 is the latest value.
The change is latest minus first: 9 - 5 = +4. The dots show the readout moving up from first to latest.
This is a readout of the pinned days, not a forecast.
A tiny first-to-latest readout: identify the first and latest daily values, compute latest minus first, and show direction without making a forecast.
highlighted = computed this step
Load daily values
Start with 4 pinned daily values.
daily values
Identify first and latest
The first value is Mon = 5 and the latest value is Thu = 9.
first and latest
Compute latest minus first
Compute change as latest minus first: 9 - 5 = +4.
latest minus first
Show the direction
The visual readout points up from first 5 to latest 9; this is not a forecast.