- Annual precipitation of less than 250 millimeters (10 inches) is required for all true desert climates.

- Most deserts receive less than 50 millimeters (2 inches) per year.

Low humidity:

- The relative humidity is low resulting from the little precipitation.

High temperatures:

- Summers are typically extremely hot with mean daily maxima around 38 °C (100 °F).

- Mean winter temperatures are normally above freezing, but frost and even snow occur in some places.

- The diurnal temperature range is often extreme, exceeding 22 °C (40 °F).

- Daily fluctuations of 50 °F (28 °C) are not uncommon.

High rates of evaporation:

- Evaporation rates exceed precipitation with the high daytime temperatures.

- Relative humidity is extremely low.

Wind

- Deserts are normally very windy places and high-speed winds are frequent in most deserts.

- Strong winds facilitate evaporation.

- Deserts with sparse vegetation are prone to sand storms