The climatic condition of the district varies from place to place as well as season to season. The climate is largely influenced by the nature of terrain depending upon altitude and location of place. It may broadly be divided into four seasons in a year :
(1) the cold weather season is from December to February,
(2) March to May is the pre-monsoon season of thunders storms follows by,
(3) the South –West monsoon from June to about the middle of October and
(4) the second half of October to November which constitutes the post monsoon or the retreating monsoon period and is a period of transition.
In the foot hills or low high belt area of the district, the climatic condition is moderate in comparison to high belt areas, where during winter is very cold and chill, and in summer is pleasant. December and January are generally the coldest month, and July and August are warmest months.
Annual rainfall in the South is heavier than that in the Northern areas of the district. During the monsoon period more than 70 percent of the rain over the Southern half occurs while in the Northern portions it is about 60 percent. Variability of rain fall for the monsoon and the year ,as a whole, are relatively small. Average Annual Rainfall of the district Headquarter, Ziro recorded as 934.88 Cms.during, 2000.
Relative humidity is always high throughout the year except in the winter months being slightly less humid. In the cold season, the sky is abscurred on many mornings due to lifted fog which clears with the advance of the day generally, moderately clouded in the period of March to May, heavily clouded to overcast in the monsoon season and clear or slightly clouded during the post monsoon season. Winds are generally light strong katabatic winds down the valleys are experienced as local effect produced by the nature of terrain.