The weather on the Indian Subcontinent is governed by the monsoons, an Arabic word which means "seasons". During the Spring and summer, the ITCZ (intertropical Convergence Zone) is pushed northward over the Himalayas by the increasing land temperatures. Cool, moist air from the oceans is drawn in to replace the rising hot air and the Summer Southwest Monsoon results. These begin in southwest India in the beginning of June and spreads rain northward, reaching Delhi around the beginning of July.

The situation reverses itself in the fall when the ITCZ falls far south of the equator. Rain follows from the Northeast Monsoon, giving southeastern India (Chennai and Trichy, for example) their highest amount of rainfall from mid-October through December.

The only part of India that misses the variances of monsoon weather is Ladakh, which is cut off from the monsoon clouds by the mountains which surround it. Ladakh, which lies at an altitude of about 11,000 feet, is a high altitude desert and is relatively dry all year around. Just very, very cold in the winter! The best time to visit Ladakh is April through September, making it the perfect destination for summer time travel to India.

For the most part, the best months to visit the "favorite" tourist destinations in north India, are October through April, but this doesn't mean you can't go at other times - it depends on your resilience in heat, and how badly you want to miss the crowds. Much of northern India - notably New Delhi and Varanasi as well as the Kathmandu Valley are subject to very thick morning fogs in January. Expect cancelled flights and, in Varanasi, cancelled Ganges boat rides.

The Rajasthan desert, and even New Delhi, can get surprisingly cold at night during January and February. Be sure to take a fairly heavy jacket with you if you are there at this time.

If you are headed for the Himalayas (below 10,000 ft.), the clearest mountain views are usually in November. October can sometimes still be cloudy with an occasional heavy rainstorm. After November, the dust and pollution begin to settle in and January can be foggy. If you will be over 10,000 ft, dust and pollution are not such issues.

 

City Month Average High Average Low Precipitation
Agra January 75 45 0.5 inch
  February 79 46 0.5
  March 89 55 0.3
  April 102 79 0.4
  May 107 86 2.5
  June 105 84 2.5
  July 95 82 8.5
  August 92 79 8.1
  September 94 75 4.5
  October 95 62 0.8
  November 85 50 0.2
  December 76 45 0.2
         
Calcutta January 80 57 0.3 inch
  February 85 60 1.5
  March 95 71 1.4
  April 98 75 1.9
  May 97 78 5.7
  June 94 79 13
  July 90 78 13
  August 88 78 14
  September 90 77 10
  October 89 75 4.7
  November 85 64 0.9
  December 79 56 0.3
         
Chennai January 87 69 1.2 inch
(Madras) February 87 70 1.2
  March 80 70 1.2
  April 96 79 1.3
  May 102 84 1.3
  June 102 85 1.3
  July 97 79 3.0
  August 97 78 3.1
  September 94 77 5.1
  October 89 77 10
  November 86 76 12
  December 82 71 5.0
         
Darjeeling January 42 34 0.3 inch
7,400 ft. February 47 35 1.1
  March 54 42 1.8
  April 62 50 4.2
  May 64 52 9.6
  June 65 56 24
  July 67 58 35
  August 67 56 26
  September 65 57 20
  October 61 52 5.5
  November 55 42 0.7 (best views)
  December 52 38 0.4
         
Delhi January 72 40 1 inch
  February 73 48 0.7
  March 88 56 0.5
  April 98 67 0.3
  May 107 80 0.5 (Humid!)
  June 101 84 3.0
  July 98 80 8.1
  August 92 78 7.1
  September 92 75 4.5
  October 90 65 0.4
  November 85 51 0.2
  December 75 44 0.3
         
Goa January 85 70 0.2 inch
  February 85 72 0.2
  March 87 75 0.2
  April 89 80 0.8
  May 91 81 2.7
  June 88 77 29.4
  July 86 76 32.1
  August 83 75 16.1
  September 85 76 9.4
  October 85 75 3.5
  November 87 72 1.4
  December 85 70 0.3
         
Jaipur January 75 48 0.5 inch
  February 78 51 0.4
  March 89 56 0.4
  April 90 68 0.6
  May 107 79 0.5
  June 104 81 2.3
  July 95 77 7.5
  August 92 75 8.5
  September 94 73 3.5
  October 93 71 0.5
  November 85 55 0.1
  December 76 49 0.3
         
         
Mumbai January 85 66 0.1
(Bombay) February 85 67 0.1
  March 86 73 0.2
  April 89 75 0.1
  May 93 80 0.8
  June 89 78 20
  July 86 74 24
  August 84 76 14
  September 87 77 10
  October 87 76 2.5
  November 89 73 0.6
  December 87 68 0.1
         
Varanasi January 76 42 1.0 (foggy mornings)
  February 80 50 0.3
  March 92 62 0.5
  April 102 75 0.1
  May 106 80 0.4
  June 103 83 4.5
  July 93 79 13.5
  August 90 75 10
  September 90 72 1.7
  October 89 71 1.5
  November 84 59 1.1
  December 79 48 0.1
         

Nepal

        
         
Kathmandu January 65 35 0.5 (foggy mornings)
4,400 ft. February 68 39 0.7
  March 78 45 0.9
  April 80 53 2.0
  May 86 61 5.0
  June 85 67 11
  July 83 67 15
  August 83 68 14
  September 82 67 6.0
  October 80 55 1.0
  November 74 45 0.5
  December 66 37 0.9
         
Pokhara January 70 42 0.4
2,900 ft. February 73 45 1.5
  March 82 52 2.0
  April 90 61 3.2
  May 90 67 10
  June 88 70 23
  July 89 72 26
  August 88 68 28
  September 85 67 17
  October 82 64 9
  November 75 55 4
  December 70 44 0.2