Nepal sees enormous variation in weather between the plains of the Terai, the mid-hills where Kathmandu and Pokhara are located, and the high Himalaya. Most parts of Nepal are pretty hot in April, with the exception of settlements high in the mountains, but even these experience warm and sunny days. Kathmandu and Pokhara see temperatures into the 90s Fahrenheit. Rain is scarce in April, but winds (often filled with dust) pick up in the spring. The Terai can often be uncomfortably hot.
Crowds & Costs
April (and October) see the most travelers in Nepal. While crowds are hardly a problem in most places around the country, popular trekking areas—the Everest and Annapurna regions especially—do see a steady stream of trekkers. The best lodges fill up fast at this time, and domestic flights and long-distance tourist buses should be booked as far in advance as possible. Many hotels charge a peak-season rate, which is higher than the low-season rate.
Trekking trails are at their best in April. Conditions are dry, views are clear (but not quite as reliable as in October), and daytime temperatures are warm even high in the mountains. Spring is the best time to tackle treks with high passes. While it's always a good idea to trek with a guide in Nepal, one of the advantages really shows at this time: they can help secure your accommodation on the busiest trails.
For more on trekking in Nepal, check out this article.
Where to Go
Treks in the high Himalaya and the rainshadow of the Himalaya (Mustang and Upper Dolpo) can be enjoyed comfortably in April. Temperatures will still be cold at night at higher altitudes, but daytime conditions are almost always sunny and warm.
Kathmandu, on the other hand, will be very hot and dusty in the build-up to monsoon. Head out to the hills, mountains, and rivers instead, where you'll enjoy cleaner air.
What to Do
Trekking in the mountains tops the list of reasons to visit Nepal in April. Both camping and teahouse treks in most regions are accessible and at their best. Travelers interested in flowers and botany will enjoy trekking through colorful rhododendron forests throughout the month.
April is also usually the start of the brief Everest climbing season—there's only a short window in which conditions are suitable for ascending the highest mountain in the world. If (slightly) smaller mountains are more your cup of tea, April is also a good time to take a crack at a trekking peak, such as Island Peak or Mera Peak.
White-water rafting and kayaking trips are an enjoyable activity in April. Water levels in the months leading up to the monsoon (starting in June) can be on the low side, so some rivers are better than others in April for white-water activities. For more on whitewater rafting in Nepal, keep reading here. Mountain biking is another good April activity, as trails will largely be dry.
Traditional Nepali festivals (whether Hindu or Buddhist) usually follow a lunar calendar. This means that some festivals that fall in April one year may be in March or May the next. Some festivals that often fall in April are:
Rato Machchendranath, a Patan festival during which a diety statue is pulled through the streets in an enormous chariot for several days.
Nepali New Year, particularly lively in Bhaktapur, where the Bisket Jatra chariot festival is held.
Buddha Jayanti, or Buddha's birthday, is especially vibrant in Buddhist communities, such as the Boudhanath area of Kathmandu.
Traveling to Nepal in April? Check out these great itineraries.
Lower Mustang Trek: This is a great option if you're short on time but still wish to experience the stark beauty of Mustang. It's much cooler than some other parts of the country in April. Mustang is part of an ancient trade route to Tibet, up the Kali Gandaki river, and offers one of the most developed trails with comfortable teahouses run by Gurung and Thakali families.
Upper Dolpo Trek: This long expedition can be the adventure of a lifetime, and requires fitness, stamina, and excellent preparation. But the rewards are worth it: Tibetan Buddhist culture, some of the oldest monasteries in the country, the spectacular Lake Phoksundo, rare wildlife, and a real sense of being in the wilderness.
Climb Island Peak: For experienced trekkers who want to try their hand at mountain climbing, or less-experienced climbers looking for a good challenge, Island Peak (20,305 feet) is the perfect option in the Himalaya.