Weather conditions are ideal for trekking in the Everest region in April. Although Kathmandu can be getting uncomfortably hot throughout April, temperatures in the mountains are still cooler: average April temperatures in Namche Bazaar (11,290 feet/3440 meters), an essential stop on the Everest Base Camp (EBC) trek, are 34°F (1°C) to 53°F (12°C). Temperatures will be colder at higher elevations.
The chance of rain is also very low in April. Later in the month, humidity may increase, somewhat obscuring some of the mountains. The skies aren't as clear in March and April as in the winter, but the warmth-to-visibility ratio is in your favor.
Crowds & Costs
These lovely weather conditions have not gone unnoticed by trekkers—April is a busy month on the EBC trail. Accommodation on the standard EBC route fills up quickly at this time, so it's important to trek with a good guide who will secure a decent bed for you in a teahouse. Alternatively, you can opt for an off-shoot of the EBC trek or an alternative route in the area. These are generally much less busy than the classic route.
If you're certain the classic EBC trek is your goal, then April's a good time to do it. But, if you'd prefer quieter trails and views unobstructed by other trekkers' heads, alternative routes overlap with EBC but take you along quieter paths, too.
The Gokyo Lakes trek diverges towards the spectacular turquoise glacial lakes, and also gives great views of Everest and friends. The Three Passes trek traverses three challenging high passes in the region, and is a good option for experienced trekkers. The Tengboche Monastery trek takes you to one of the most important Tibetan Buddhist monasteries in Nepal, and the Dingboche trek is similar but continues a little further to the small settlement of Dingboche. The Ama Dablam Base Camp trek is also a great way to visit a mountain that most people only see from a distance when trekking in this region.
To follow a longer, more remote route to Everest, check out the Arun Valley to Everest Base Camp Trek. The Arun Valley is between the Sagarmatha and Makalu-Barun National Parks. The trek starts at Tumlingtar, east of Everest, and joins the main EBC trail at Kala Pattar.
April is also a good time to tackle a trekking peak, if you're up for more of a challenge. If you have high-altitude climbing experience, a trekking peak is a good introduction to Himalayan climbing. Island Peak (20,305 feet/6,189 m) is challenging but not too technical. The trek to get there follows much of the traditional EBC trek, so if this is your first time in the region you can see what all the fuss is about and go somewhere less explored.
Mera Peak ( 21,246 feet/ 6,476 m) is Nepal's highest trekking peak, and is also in the Everest region. The trek there is particularly special, as it requires trekking through the remote Hinku and Hongu Valleys, which veer off the main EBC trail before you reach Namche Bazaar.
What to Bring
It's wise to be prepared for all eventualities in April (without going overboard with the packing). A good three-season sleeping bag, a down jacket, merino base layers, and a rain jacket are important things to bring. Read more about the what to pack for trekking in the Himalaya in the following article: Trekking Gear List for Nepal.
Getting There & Away
The quickest and easiest way of getting to the Everest region in April is to fly from Kathmandu to Lukla. However, these flights are often delayed or canceled because of the weather or conditions in Kathmandu, Lukla, or en route. Even though rainfall is low in April, Kathmandu becomes very smoggy and dusty leading up to the monsoon in June, possibly causing delays. Flights also fill up quickly in April, so it's important to book as far ahead as possible.
To make an adventure of getting to Lukla, it's possible to walk most of the way (after a day's Jeep ride from Kathmandu). The trail from Jiri to Lukla is called the 'Pioneers' Route' because it was the trekking trail that early Western mountaineers took to access the Everest region, before the airport was built in Lukla.
Similarly, it's possible to fly from Kathmandu to Phaplu and trek to Lukla through the Solukhumbu region. It's not a highly-frequented trek, but those travelers who make the effort tend to appreciate the more gradual ascent to the high altitudes of the Khumbu. These treks add 4-7 days to more standard itineraries in the Everest region.
Events in April
The Sherpa people who live in the Everest region are primarily Tibetan Buddhist in culture and religion. Most of Nepal's Hindu-derived festivals are not widely celebrated in the mountains. However, when passing through Kathmandu before or after your trek, you may encounter Nepali New Year celebrations. Traditional celebrations follow a lunar calendar so their dates change, but Nepali New Year usually falls from mid-to-late April.