Twelve months of the Thai fishing year are twelve different countries, in fishing terms. The Andaman is open and benign in February and effectively closed in July. The Bangkok pay-lakes fish well year-round but are stifling in April and beautiful in December. The northern reservoirs swing with rainfall, the southern jungle rivers swing with rainfall, and the Gulf is choppy when the Andaman is calm and vice versa.
This section is the calendar — twelve pages, one per month, each covering the weather, the water conditions, what's biting where, the recommended fisheries, and the things to avoid.
The two monsoons, in one paragraph
The southwest monsoon runs roughly May through October. It brings heavy and frequent rain to the western (Andaman) coast and to the central plain. It largely shuts down the Andaman charter business — the offshore swell and the rain make most operators stand down between June and September, and the ones who keep running do shorter, closer-in trips. The northeast monsoon runs roughly November through February. It brings drier, cooler weather to the western side (this is high season for the Andaman) and brings unsettled, choppy conditions to the eastern (Gulf) coast. The shoulder months — March, April, October — sit between the monsoons and often offer the best compromise dates if you want both coasts open at once.
For the Bangkok pay-lake scene, the monsoon matters less than the heat. Pay-lakes fish year-round. April is brutally hot. December and January are pleasantly cool by Bangkok standards.
How to use the calendar
If you've already booked your dates, jump straight to that month and read what's available to you. If you're flexible, the calendar pages will help you choose between the genuinely productive options for any given month and the slow ones.
A few rules of thumb to use alongside the monthly pages:
- Bangkok freshwater is always available. Pay-lakes don't really have an off-season, and the species mix doesn't change month to month. The only seasonal factor is comfort — long days on a covered platform are noticeably nicer in the cool months.
- Andaman saltwater is best November–April. Inside that window, sailfish peak January–March, GT popping is good year-round when the boats are running, and the deep jigging produces month after month.
- The Gulf is most reliable March–September. It's not as dramatic a shift as the Andaman, but the Gulf gets its best weather windows when the southwest monsoon is keeping the western side wet.
- The northern reservoirs and jungle rivers fish best November–March. Lower water in the cool months concentrates the fish and makes the fly fishery genuinely productive. Wet-season trips are possible but harder.
The pages
- January — peak Andaman season, cool Bangkok days, the perfect month if you can choose any.
- February — sailfish peak begins, popping windows open, lake fishing comfortable.
- March — last reliable Andaman month before the heat builds, transition to summer in Bangkok.
- April — the hottest month in central Thailand. Andaman still mostly fishable. Plan for early starts.
- May — southwest monsoon arrives. Andaman closes for serious anglers. Bangkok pay-lakes uncrowded.
- June — full wet season. Lake fishing fine. Saltwater limited to short Gulf trips.
- July — peak rainy month. Most ambitious trips deferred. Pay-lake bargain pricing.
- August — wet, warm, productive on the freshwater side; quiet on saltwater.
- September — late monsoon, but transition begins. Andaman starts re-opening late in the month.
- October — the shoulder. Wet windows still possible. Sailfish season starts. Northern rivers begin to drop.
- November — high season opens. Cool weather arrives in central Thailand. Andaman charters resume in full.
- December — peak month for many. Cool, dry, busy. Book ahead.
A note on year-to-year variation
These are general patterns, not guarantees. The southwest monsoon arrives later in some years and earlier in others. The sailfish bite peaks in January in some seasons and not until March in others. The cool snap in central Thailand sometimes arrives in mid-November and sometimes not until early January. Use the calendar as a planning starting point, then check actual current conditions — water temperature, recent catch reports from the major operators, the BMA weather forecast for Bangkok — before you commit to specific venues.
The calendar is also worth re-reading after you arrive. A two-day window of unexpected calm during the monsoon can open up an offshore trip that wouldn't normally be on the table. A late cold snap in February can make the snakehead fishing in the Bangkok lure venues drop off sharply. Local knowledge — your guide, your boat captain, the cashier at the pay-lake — beats the calendar every time.
