The conversion

6°C = 42.8°F

°F = (°C × 9/5) + 32, so (6 × 9/5) + 32 = 42.8.

As an outdoor air temperature, 6 °C sits in the cold 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 6 °C.
CelsiusFahrenheit
1 °C33.8 °F
2 °C35.6 °F
3 °C37.4 °F
4 °C39.2 °F
5 °C41 °F
6 °C42.8 °F
7 °C44.6 °F
8 °C46.4 °F
9 °C48.2 °F
10 °C50 °F
11 °C51.8 °F

The other direction

42.8 °F converts back to 6 °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.