Lombok / Sumbawa Surf Seasons & Weather
The Indonesian archipelago covers three time zones, stretched across the equator between the hot, dry Australian land mass to the south, and the hot, wet Asian land mass to the north. Indonesia’s climate is tropical year round with seasons divide in two: wet and dry.
The wet season begins in mid October and lasts until March, with most rain measured in January and February, when high pressure flowing south from the Asian mainland combines with humid air from the Indian Ocean to bring rain throughout the archipelago – although the northern and western islands get more rain than those in the south and east.
The dry season begins in March and runs through September/October, when high pressure over Australia pushes north blanketing Indonesia with warm, dry air. The dry season peaks in July and August which is also in the middle of the prime surf season.
Best season for swell in Indonesia is the southern hemisphere winter of March/April through September/October when low pressure systems in the Southern Ocean and Indian Ocean pulse ground swells toward the equator. These ground swells travel for thousands of miles, allowing them time to “unwrap” and organize before marching onto the reefs of Indonesia as perfectly groomed lines. The biggest months are typically June though August.
Prevailing winds also change with the wet and dry season. During the dry drier months of April through September trades blow ESE, or off-shore along most southerly facing breaks. January and February will see west wind which is not favorable at most of the “name” breaks, but good “off season” waves do exist. During the transition periods between changing seasons winds typically go lights and variable, with glassy conditions not uncommon.
Prime surf season is also prime weather season, which is why you have seen so many surf movies showing surfers going berserk in perfect surf, under blue sunny skies, with offshore winds adding that little bit extra.Although most of the rain falls during the wet season, rainstorms can occur at any time of year. Air temperatures range between 75° and 90° year around and water temperatures run from the mid 70’s to low 80’s. When you see people wearing wetsuits in Indonesia, it’s for reef and sun protection, not warmth.