The Weather
 There are many things that can make or break a successful ascent of Mount Everest – the weather being foremost among them. Many a climber has tried to read the winds, cloud formations, and the trails of snow while wondering, “Continue on or wait it out?”
The jet stream is one of the main factors in Everest weather, affecting winds at various altitudes. Experienced climbers generally do not attempt to summit when the winds are above 40 mph. It can be calm at one level, while winds at the summit are clocking in at hurricane force - well over 100 mph. Or the summit may be calm while lower levels are hazardous. Climbers look for a period of 4-5 days of stable weather, known as "the window," which typically comes in May.
The coldest month on Everest is January, where the summit temperature averages –33°F and can drop as low as –76°F. July is the “warmest” month, where the summit temperature averages –2°F. Precipitation falls mostly during the Indian monsoon season from June through September. However, unexpected storms can develop and drop up to 10 feet of snow on unsuspecting climbers.
The term “death zone” refers to high altitudes where the amount of oxygen in the air cannot sustain human life, specifically, above 26,250 feet. The atmospheric pressure at the top of Everest is about one-third of that at sea-level - meaning there is about a third as much air available as at sea level. Apart from that, temperatures and wind chills can drop to dangerous levels, resulting in frostbite to any exposed area.
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Summit Conditions
Weather Information Provided by CNN
Base Camp Conditions
Weather Information Provided by CNN | 
