The conversion

37°C = 98.6°F

°F = (°C × 9/5) + 32, so (37 × 9/5) + 32 = 98.6.

As an outdoor air temperature, 37 °C sits in the hot 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 37 °C.
CelsiusFahrenheit
32 °C89.6 °F
33 °C91.4 °F
34 °C93.2 °F
35 °C95 °F
36 °C96.8 °F
37 °C98.6 °F
38 °C100.4 °F
39 °C102.2 °F
40 °C104 °F
41 °C105.8 °F
42 °C107.6 °F

The other direction

98.6 °F converts back to 37 °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.