Contrary to what you might think, the best time to go on the Everest Base Camp Trek is not during the height of summer. The spring months of February through May is widely considered the peak season and is when the region is at its busiest.
Weather during these months is stable and dry – perfect for trekking and for sightseeing. The mountain is most colourful during this time as well, so you can expect verdant fields and hillsides covered in rhododendrons.
September to October is another popular trekking period on the other side of summer that tends to be a little less busy. Another way to avoid the hustle and bustle of peak season is to try some of the trek variations such as the Gokyo Lakes Trek.
Trekking in the winter months is still possible, but be prepared for temperatures below freezing. Peak summer is known as monsoon season, characterised by short, sharp downpours. The trails are very wet and trekking during these months is not advised.