Weather
As with every month in Nepal, the climate varies enormously between the Terai, the mid-hills, and the high Himalaya. In Kathmandu, highs of 68°F (20°C) can still be expected, and lows of 39°F (4°C) on average. Pokhara is a few degrees warmer, and the skies can be stunningly clear in December. In the Terai, fog is common, but December can still be quite warm, with daytime temperatures as high as 83°F (28°C) in the Chitwan area. Snowfall in the Himalayas can make trekking trails in the mountains much colder. there's practically no rain throughout Nepal in December.
Crowds & Costs
Crowds thin by December on the most popular trekking trails, like Everest or Annapurna Base Camp. Kathmandu and Pokhara also see a drop in visitors, and the Thamel and Lakeside districts of these cities (respectively) are noticeably quieter this month. Many hotels offer low-season discounts, although accommodation in some remote areas and on some trekking trails, such as Upper Mustang, completely shuts down.
Trekking Trails
Just because December sees a drop in trekkers doesn't mean hitting the trails isn't a good idea this month. Visibility is actually at its best in December. Greater preparations should be made for higher-altitude treks, such as taking warmer clothes and sleeping bags, and researching any passes that may be blocked by snow.
You may experience cold nights on lower-altitude treks, but days will likely be just right. However, places on the "other" side of the Himalaya—such as Upper Dolpo or Upper Mustang—can be inaccessible, with extremely limited or no accommodation options. Opt for lower-altitude treks unless you're an experienced winter trekker.
Check out this article for the best winter trekking options in Nepal.
Chat with a local specialist who can help organize your trip.
Where to Go
Unless you're a very experienced trekker or have spent a lot of time in the mountains during winter, the higher-altitude trekking trails should be skipped. Some local experts believe that winter (including December) is the best time to trek the lower Solu area (south of Everest), as well as the shorter treks near Pokhara. The Tamang Heritage Trail and Poon Hill treks are also good choices for winter, as they don't climb too high in elevation—see more details below.
Pokhara can be spectacular in winter, with clear mountain views every day. If you want to spend some time in a Nepali city in December, pick Pokhara over Kathmandu as the air is clearer (and check out this article for some of the city's best things to do). You'll also enjoy clear mountain views from Nagarkot, a popular town near Kathmandu: here's a five-day Nagarkot itinerary that's available in December.
What to Do
Trekking, jungle safaris, cultural tours, mountain biking, and paragliding are all enjoyable during December, due to clear skies and cool temperatures in much of the country.
Events in December
Pokhara Street Festival, Lakeside. The annual festival brings Lakeside Pokhara to life each year in the lead-up to New Year's. Organized by the Restaurant and Bar Association of Nepal, this vibrant event features live music, street food, and cultural performances.
New Year's Eve (December 31). Expect lively celebrations on the eve of the Western world's new year, particularly lively in the Thamel area of Kathmandu.
Traveling to Nepal in December? Check out these great itineraries
Tamang Heritage Trail - 7 Days. Get to know the Tamang people while trekking amid green valleys and snowcapped mountains on this moderate seven-day trek just north of Kathmandu Valley.
Ghandruk Trek & Chitwan National Park - 11 Days. Combine two classic Nepal experiences: the Ghandruk trek in the Annapurna foothills and Chitwan National Park in the lowlands of Nepal. Chitwan National Park has a wide variety of wildlife, including tigers, rhinos, elephants, and many bird species. To end the tour, you'll overnight in Namobuddha for a beautiful vantage point over the Kathmandu valley before doing some last-minute sightseeing.
More Helpful Information
Nepal in November
Nepal in January
Best Time of Year to Visit Nepal
How Many Days to Spend in Nepal