Climate in Jordan

the summer months frequently exceed 29 °C (84.2 °F) and average about 32 °C (89.6 °F). September to March are moderately cool and sometimes very cold, averaging about 3.2 °C (37.8 °F). Except in the rift depression, frost is fairly common during the winter, it may take the form of snow at the higher elevations of the north western highlands. Usually it snows a couple of times in the winter.

For a month or so before and after the summer dry season, hot, dry air from the desert, drawn by low pressure, produces strong winds from the south or southeast that sometimes reach gale force. Known in Western Asia by various names, including the khamsin, this dry, sirocco-style wind is usually accompanied by great dust clouds. Its onset is heralded by a hazy sky, a falling barometer, and a drop in relative humidity to about 10%. Within a few hours there may be a 10 °C (18.0 °F) to 15 °C (27.0 °F) rise in temperature. These windstorms ordinarily last a day or so, cause much discomfort, and destroy crops by desiccating them.

The shamal comes from the north or northwest between June and September. Steady during daytime hours but becoming a breeze at night, the shamal may blow for nine days out of ten and then repeat the process. It originates as a dry continental mass of polar air that is warmed as it passes over the Eurasian landmass