24th Session of the International Poplar Commission
Weather and health issues
Dehradun has a sub-tropical climate with cold winters, warm and colorful springs, humid and hot summers and an extended monsoon, sometimes up to mid October. Dehradun is located at altitudes between 700-1000 m (2,300-3,300 ft) above sea level and is surrounded by forests and mountains; its weather sometimes changes abruptly. October and November are very pleasant months, with average temperatures ranging from 7 to 23 degrees Celsius. It is a good period for any outdoor activity. Light woolens may be required; however, cotton cloths are preferred.
Citizens and travellers coming from the United States, Canada, or the United Kingdom, do not require any vaccination certificate or inoculations. Though normally an International Health Certificate is not asked for by immigration officials, it is better to carry one. It contains valuable information in case one needs medical attention. Travellers should have a Yellow Fever Vaccination Certificate conforming to International Health Regulation, if they originate or are transiting through yellow fever endemic countries.
Many websites provide further details on health and related issues.
Visitors may like to consult them, e.g.http://www.mustseeindia.com/India-About-India-Health-Tips-Vaccination-topic-1344.