Using the cloud base estimation formula, if actual temperature is 20 C and dew point is 5 C, what is the estimated cloud base?

Using the cloud base estimation formula, if actual temperature is 20 C and dew point is 5 C, what is the estimated cloud base?

• A. 4 units
• B. 8 units
• C. 6 units
• D. 5 units

Answer: (C)

The amount of cooling needed for air to reach its dew point controls where clouds form. A quick rule of thumb uses the difference between actual temperature and dew point, multiplying by about 400 feet per degree Celsius to estimate cloud base. Here, the temperature is 20°C and the dew point is 5°C, so the spread is 20 − 5 = 15°C. Multiply by 400 feet per degree: 15 × 400 = 6000 feet. In the problem’s unit scheme, that’s 6 units. So the estimated cloud base is 6,000 feet above the surface. The larger the spread, the higher the cloud base tends to be; a smaller spread would yield a lower base.

The amount of cooling needed for air to reach its dew point controls where clouds form. A quick rule of thumb uses the difference between actual temperature and dew point, multiplying by about 400 feet per degree Celsius to estimate cloud base.

Here, the temperature is 20°C and the dew point is 5°C, so the spread is 20 − 5 = 15°C. Multiply by 400 feet per degree: 15 × 400 = 6000 feet. In the problem’s unit scheme, that’s 6 units.

So the estimated cloud base is 6,000 feet above the surface. The larger the spread, the higher the cloud base tends to be; a smaller spread would yield a lower base.