The app allows to adjust your temperature preference. Open settings and look for the “Temperature preference adjustment” slider.
If you are hot-lover (and for example 30°C or 86°F is not boiling-hot, but quite-warm-but-still-comfortable for you), move the slider to the right.
Otherwise, if you prefer cool temperatures (and for example 22°C or 72°F is quite hot for you), move the slider to the left.
In either case I recommend moving the slider only by a few units initially (±5 units should do the trick in most cases, 7 is usually more than enough). Always check if the temperature texts match your preference when you change the setting.
The number of units is neither Celsius nor Fahrenheit. The way it is connected with any temperature scale is too complex to explain; just follow the instructions above and you should be happy 🙂