The best time to visit Delhi is between October - March, although the city remains bustling with tourists throughout the year.  If you are here not for mere fun but to try for adventure excursions then Delhi is worth visiting round the year. Nevertheless, in summers there are chances you might get affected with heat stroke or Loo as it is known locally.

Clothes to Wear in Delhi
Summer
Summer season prevails from April to August when average Maximum temperature remains around 43° C. Therefore, it will be better if you bring light cotton clothes. These clothes are fit for the summers of Delhi. Try to fully cover your body parts with appropriate clothes in order to protect yourself from heat strokes. Do carry enough of sunscreen lotions and cream and drink a lot of water. Try and not venture out with empty stomach.

Monsoon
Due to its relief, it rains moderately in Delhi during the monsoons. Normal summer clothing will do. It is wiser to carry an umbrella in order to avoid being caught at the wrong side of the monsoon. Besides, it also protects from direct sunrays. Monsoon in Delhi is very humid so try to carry as many tissues as you can.

Winter
Winters are chilly in Delhi with average day temperature hovering around 23° C. Nights are really chilly and average night temperature is around 2° to 5° C. Nevertheless, there are instances when the temperature has dipped to as low as 1° C. Heavy winter clothing is preferable. You can include Long coats and Outsiders in your luggage. In daytime, light pullovers are sufficient. But there are days when even in daytime you will require heavy woolen clothing, especially during cold waves. Mornings are very foggy and you can easily witness a thick layer of smog suspended in the atmosphere.