The peak seasons for travelling in Nepal are from September to November and March to May. Flights to Kathmandu are most expensive during these times. To keep costs down, travel on the edge of these seasons and book in advance.
Tourist visas are available on arrival for citizens of most countries at the designated land borders for USD25, for 15 days, USD40 for 30 days and USD100 for 90 days . They can only be granted for a maximum of 150 days in each 12 month period.
To extend your tourist visa, visit the Nepal Immigration Office in Kathmandu with your passport and another photo, and pay US $2 for every day past your visa you want to stay, up to the maximum of 150 days per year.Climate:
Heavy monsoonal rains from June to September - the rains are generally lighter high in the Himalayas than in Kathmandu, though the mountain peaks are often not visible due to clouds.
In the Kathmandu Valley & Pokhara - monsoon rains typically consist of an hour or two of rain every two or three days. The rains clean the air, streets, & cool the air. If you come, bring an umbrella, expect lower lodging prices & fewer tourists. Clear and cool weather from October to December - after the monsoon, there is little dust in the air so this is the best season to visit the hilly and mountainous regions.
Cold from January to March, with the temperature in Kathmandu often dropping as low as 0°C (32°F)
Dry and warm weather from April to June - there is an abundance of blooming flowers in the Himalayas at this time, with rhododendrons, in particular, adding a splash of colour to the landscape.
World Heriatge Sites
UNESCO cultural world heritage site have eight site respectively Kathmandu Durbar Square, Patan Durbar Square, Bhaktapur Durbar Square, Swayambhunath, Boudhanath, Pashupatinath, Changunarayan and Lumbini. Seven Cultural World Heritage Sites are situated within 20 kms of radius, in the Kathmandu Valley accept Lumbini. Another UNESCO natural world heritage site including two site respectively Sagarmatha National Park ( Mt. Everest National Park ) and Chitwan National Park.