Myanmar climate report

Myanmar is situated in the tropical climate region, a region that is highly vulnerable to impacts from climate change. Therefore, information about climate change in Myanmar is in high demand. In this report, changing of various observed climate parameters were estimated and analyzed. New normal values for minimum and maximum temperature and rainfall, as well as for monsoon onset and withdrawal dates, were calculated for the period 1981-2010. Normal monthly mean temperature and rainfall values for the whole country of Myanmar were calculated for the new normal period and compared to values of the previous normal period 1961-1990. Frequency of days for different ranges of temperature and rainfall were computed, in addition to frequency of 10 years wind direction and wind speed. Trends of minimum and maximum temperature were also calculated and analyzed. From 1961-1990 to 1981-2010, the maximum temperature has increased at almost every station of Myanmar, whereas the minimum temperature has decreased at most of the stations. The average normal maximum temperature for the whole country of Myanmar has increased for all months, except February and December. The normal annual mean maximum temperature increased by 0.5 °C from 1961-1990 to 1981-2010. The average normal minimum temperature of Myanmar has decreased for the months January-May and SeptemberDecember, while it has not changed significantly for the months June-August. The normal rainfall pattern has decreased for the months May-August, for the other months it has not changed significantly. In the pre-monsoon and mid-monsoon seasons, the amount of rainfall has decreased over the whole country, while it has been unchanged in the months of winter and post-monsoon seasons over Myanmar, from 1961-1990 to 1981-2010. In the new normal period, the onset date of the monsoon is later and the withdrawal date is earlier than in the old normal period, which means that the duration of the rainy season has decreased. The normal duration of the monsoon period was 144 days in the period 1961-1990 and 121 days in the period of 1981-2010. Compared to the new normal (1981 to 2010) duration of monsoon period, trend studies indicate however a possible increase in the duration of the rainy season in the recent years, and more studies of long-term rainfall trends are needed.