Unlike the rest of Indonesia, the surf season is Nov-March during the NE monsoon which blow straight offshore to the WSW facing coastline. There is obviously lots of waves in the austral winter season, but it’s plagued by almost constant WSW onshore winds so wave shape and quality won’t be optimum. Of course, there is less swell during summer, but the regulation 2-5ft conditions will provide clean fun intermediate style waves for surfers looking for friendly size surf and the adventure of mainland Sumatra travelling. There is 400km (250mi) of potential fetch in the Andaman Sea and the NE monsoon kicks up mushy 1-3ft (0.3-1m) windswells on the east coast. If the West coast goes flat, there’s always a chance of rideable, unchartered waves in Banda Aceh or Lhokseumawe. With 2ft (0.6m) maximum tidal range, tides are rarely a problem, but winds really need to be right.
Aceh-Sumatra has a tropical humid climate and experiences relatively little change in temps from season to season. The weather is warm to hot with temps ranging from 23°C to 30°C (74-86ºF). There is a dry season that generally lasts from March through August influenced by the Australian continental air masses and a rainy season from October to January, when the Asian and Pacific Ocean air masses mix. Northern Sumatra experiences the most precipitation when monsoon clouds unleash heavy downpours and average annual rainfall is 1600mm (64in). Winds are moderate and generally predictable, with monsoons usually blowing in from the south and east between June and September and from the northwest during December to March. Boardshorts are sufficient with rashies for protection from the sun & reef.