To convert degrees Fahrenheit (°F) to degrees Celsius (°C), you can use the formula:
\[ °C = (°F - 32) \times \frac{5}{9} \]
For 70° F, the calculation would be:
\[ °C = (70 - 32) \times \frac{5}{9} \]
\[ °C = 38 \times \frac{5}{9} \]
\[ °C \approx 21.11 \]
So, 70° F is approximately 21.1° C.