To convert a temperature from degrees Celsius to degrees Fahrenheit, you can use the following formula:

$$°F = (°C × 9/5) + 32$$

Where:

- °F is the temperature in degrees Fahrenheit

- °C is the temperature in degrees Celsius

So, to convert 28-30 degrees Celsius to Fahrenheit:

$$°F = (28 °C × 9/5) + 32 = 82.4 °F$$

$$°F = (30 °C × 9/5) + 32 = 86 °F$$

Therefore, 28-30 degrees Celsius is equivalent to 82.4-86 degrees Fahrenheit.