18 degrees Celsius:

* Formula: (°C × 9/5) + 32 = °F

* Calculation: (18 × 9/5) + 32 = 64.4 °F

30 degrees Celsius:

* Formula: (°C × 9/5) + 32 = °F

* Calculation: (30 × 9/5) + 32 = 86 °F

Therefore:

* 18 degrees Celsius is equal to 64.4 degrees Fahrenheit.

* 30 degrees Celsius is equal to 86 degrees Fahrenheit.