seasonal forecast for May, June and July

Updated 14 May 2018

A transition to the Southwest Monsoon is expected in June 2018. The prevailing inter-monsoon conditions of light and variable winds and localised but frequent shower activities can be expected in May 2018. The Southwest Monsoon season typically prevails over the region between June and October, and is associated with the traditional dry (rainy) season of the southern (northern) ASEAN region.

During the Southwest Monsoon season in the northern ASEAN region, rainy conditions can be expected due to the presence of the monsoon rain band over the northern parts of Southeast Asia. For the May-June-July 2018 season, slightly below-normal to near-normal rainfall are forecast for the region.

Conversely, in the southern ASEAN region, extended periods of dry weather can be expected during the May – July 2018 period. This could lead to an escalation of hotspot activities with smoke plumes, in particular, in parts of Sumatra and Kalimantan. Slightly below-normal to near-normal rainfall are expected over most parts of the region during the May – July 2018 period. In addition, below-normal to slightly below-normal rainfall are expected for Java, Nusa Tenggara and Timor Leste for the early part of the Southwest Monsoon season.



  • Legend
  • Above Normal
    (67th to 100th percentile)
  • Slightly Above Normal
    (50th to 83rd percentile)
  • Normal
    (33rd to 67th percentile)
  • Slightly Below Normal
    (17th to 50rd percentile)
  • Below Normal
    (0 to 33rd percentile)