Is there anywhere that lists what icons and graphics mean?

I've tried googling around to see if I can find out if there's some online manual for icons, usually they make sense just by looking at them like heart rate or steps etc but there's one that isn't immediately obvious

The weather icon bar, like I get it's showing the weather, its showing the temperature, but the bar is that showing the temperature on a bar with the dark bit being cold and the lighter bit being warmer?

Really surprised there isn't a wiki for iconography for the icons to explain what each is for, even if most are super obvious