The conversion

25°C = 77°F

°F = (°C × 9/5) + 32, so (25 × 9/5) + 32 = 77.

As an outdoor air temperature, 25 °C sits in the warm band. The other scale is on the dial beside it in the app, so a reading like this needs no conversion at all.

Convert something else

68°F

The range either side

Neighbouring values, for when the number you actually wanted was a degree or two away.

Celsius to Fahrenheit either side of 25 °C.
CelsiusFahrenheit
20 °C68 °F
21 °C69.8 °F
22 °C71.6 °F
23 °C73.4 °F
24 °C75.2 °F
25 °C77 °F
26 °C78.8 °F
27 °C80.6 °F
28 °C82.4 °F
29 °C84.2 °F
30 °C86 °F

The other direction

77 °F converts back to 25 °C, which is the same relationship read the other way. Going from Fahrenheit to Celsius, subtract 32 first and then multiply by 5/9 — doing it in the other order is the usual mistake and produces a plausible-looking wrong answer.

The full converter handles any value, in either direction, including kelvin, and shows the formula as it works.