Weather Matters More

Southeast Asia Pilot – August 2025

Why Weather Matters More Here:

In many parts of the world, cruising is all about catching a fair wind and avoiding the occasional storm. In Southeast Asia, the stakes are higher. Here, the weather isn’t just background – it’s the stage manager for your entire voyage.

With two distinct monsoon systems, microclimates shaped by rugged coastlines and occasional tropical storms, timing your passages is just as important as plotting your course.

The Two Monsoons: Your Seasonal Roadmap

Northeast Monsoon (Nov–Apr)
⇒ Dry, cooler air dominates the Andaman Sea and Gulf of Thailand
⇒ Best for cruising Thailand’s west coast, Langkawi, and the Andaman Islands
⇒ Expect steady NE winds, calm seas on western shores, and occasional early-season squalls

Southwest Monsoon (May–Oct)
⇒ Warmer, wetter conditions prevail, especially in the Andaman Sea
⇒ The “dry” side shifts eastward – Indonesia’s eastern islands and the Philippines become prime cruising grounds
⇒ SW winds can bring swell and reduced visibility in the west

Microclimates: Expect the Unexpected

In Raja Ampat, a squall can roll in under blue skies. In Palawan, afternoon katabatic winds funnel down mountain slopes without warning. Always check multiple forecasts – and expect local quirks to override the models.

Tropical Storms & Typhoons

While rare in the equatorial zone, typhoons can affect the northern Philippines, South China Sea, and occasionally the Gulf of Thailand between June and November. Keep an eye on regional cyclone tracking during this period.

Safety Through Seasonal Planning

⇒ Plan your cruising route around monsoon patterns – don’t fight the seasons
⇒ Use local knowledge from marinas, fishing fleets and other cruisers
⇒ Factor in shelter options every 50-80 nm when passage making

Bottom Line:

The weather in Southeast Asia isn’t just something to “keep an eye on.” It’s the foundation for safe, comfortable, and memorable cruising.

For anchorage notes, charts other useful information, see Southeast Asia Pilot – 7th Edition with detailed coverage of over 600 anchorages across nine countries, from the Andaman Sea to the Spice Islands. Available now in print and digital editions.

Order Southeast Asia Pilot

Southeast Asia Pilot and Phuket Publicity Services do their best to ensure that the information on this website is accurate. However, good seamanship demands that seafarers check critical information carefully with relevant sources to ensure it is up to date.FacebookLinkedInInstagram