Nepal's monsoon starts in mid-June and continues until mid-September. The Everest Region, along with the rest of the country, records its highest annual rainfall in July and August. It also has the warmest temperatures; while it's never 'hot' in the high Himalaya, average highs in Namche Bazaar in August are around 60°F (16°C).
The higher into the mountains you go, the cooler the temperatures and the lower the rainfall. There's also a chance that landslides will block trekking trails in August, and that paths will be muddy. But, it doesn't tend to rain all day every day. If you're prepared for wet conditions and understand that the mountain views may not be perfect, it's usually possible to trek to Everest Base Camp (EBC) in August.
Crowds & Costs
August is low-season in the Everest region. You won't have any trouble getting a bed in teahouses that happen to be open en route, although many of them will have shut for the season. You won't meet many other trekkers along the way, either.
As long as you're aware that conditions on the way to EBC won't be optimal, it's usually possible to trek all the way there in August. You'll probably experience the most rainfall at lower elevations (although nowhere in the Everest region is exactly 'low'); the higher you go, the less rain there will be.
Alternatively, a good option in August is to base yourself in Namche Bazaar and go for day hikes from there. You can explore the Everest region without going all the way to EBC. If the rain puts a halt to your plans some days you can enjoy the cafes, shops, and cultural attractions of the little Sherpa town. You may well get some good mountain views right after a bout of rain. Namche Bazaar is two days' walk from Lukla.
What to Bring
Good rain gear is essential for trekking in August. Some trekkers prefer using an umbrella to avoid sweating in warm temperatures under layers of rain clothing, but as the temperatures in the Everest region aren't that warm, you might prefer to go for a good raincoat and pants.
Don't fail to bring some entertainment—whether a book, e-reader, pack of cards, or sketching supplies—for days when your travel is delayed, or when conditions are too wet to walk.
Check out this handy guide to packing for a trek in the Himalaya: Trekking Gear List for Nepal.
Getting There & Away
The easiest way of getting to the Everest region in August is to fly from Kathmandu to Lukla—in fact, it's the only way. The overland routes from Jiri or Phaplu will likely be affected by landslides during August. However, flying in August isn't always hassle-free either. Flights are often delayed or canceled because of the weather, and even more so in August. Leave yourself plenty of time to make important international connections when booking flights out of Lukla.
Events in August
While the Everest region itself doesn't have any specific events or festivals in August, most travelers pass through Kathmandu on the way, and there are some noteworthy festivals that often fall in August. Hindu and Buddhist festivals more often than not follow a lunar calendar, so some festivals that fall in August one year will fall in September another. Festivals to keep an eye out for in August include:
- Naag Panchami, which celebrates the serpent god, Naag. The place to be for this festival is Naag Pokhari, in central Kathmandu.
- Janai Purnima, also known as the sacred thread festival. Upper-caste Hindu men change the sacred threads that they wear around their bodies.
- Gai Jatra, in which families who have experienced a death in the family the previous year come out to remember their loved ones. Children dress up as cows.
- Krishna Janmasthami, celebrating the birthday of Hindu Lord Krishna. The Krishna Mandir at Patan Durbar Square is the place to be for this festival.
- Teej, a festival in which Hindu women dance, pray, and fast for the health of their husbands.