Precipitation is 0.5 mm/a. Rainfalls occur mostly in winter and sometimes in summer in a few days after several decades of drought. The average relative humidityRelative humidity of the air is 35%, with a maximum of only 48% in December and a minimum of 28% in June and July. Dew events are very seldom. In the Gilf Kebir, there may have been a 20- to 30-year rainy period in the last 200 years. The average annual air temperature is 23 °C, with an average minimum of 11 °C in January and an average maximum of 30 °C in June, July, and August. Frost can occur in January and February. The upper 40 cm of the soil are affected by daily temperature fluctuation (< 10 to > 40 °C), and the lower parts are affected by only annual temperature changing. About 6.3% of the year, the area is hit by sandstorms that reshape dunes, set them in motion, and rub stones by sand blowerSand blower that occur on the soil surface.