Ringed by high ridges, Iran has a mountain-and-plateau climate that belies its location next to two major bodies of water. The cold Asian high dominates in winter, but as it waxes and wanes, temperatures across parts of the interior may shoot above 16°C/60°F, or drop below –18°C/0°F. Mediterranean depressions arrive about once a week on average from January to March, often bearing a respectable amount of rain or snow. However, most of the country averages less than 250mm/10in of annual precipitation, with higher amounts toward the west. When the country's northern peaks intercept Asian fronts, the Caspian coast – especially the western part – can get very gloomy. Some spots average more than 100 wet days and 2000mm/79in of precipitation each year. The dry summer features steady northwest winds and temperatures on the plateau (including Tehran) that rank as the hottest in the world for their elevation. Humidity levels are modest except on the Persian Gulf coast, which is just as oppressively hot and humid as Kuwait or Qatar. The lowlands of the far southwest (next to Iraq) are hotter still.