Ayutthaya Weather Month by Month

Two numbers decide a day here: how hot it is, and how much rain falls. The ruins are roofless brick on open ground with the trees at the edges, so both land on you directly. Figures below are Thai Meteorological Department 30-year normals for Phra Nakhon Si Ayutthaya. If the month is fixed and the day is not, an Ayutthaya half day tour that keeps you in an air-conditioned vehicle between stops is worth more here than almost anywhere.

What the weather does to a visit here

Heat is the constraint, not rain. From March to May the average high sits between 35.4 and 35.9°C, and there is nowhere in the central park to get out of it. That turns a five-hour walking plan into a three-hour one, and it is the reason the guided days build lunch into the middle of the afternoon.

Rain behaves differently from what most visitors expect. The wet season delivers most of the year's 1,423.8 mm between May and October, and it comes in heavy bursts rather than steady drizzle. Nothing closes for it. What it does do is fill the rivers, which is the other half of the picture: the water that makes this island beautiful is the same water that put Wat Chaiwatthanaram under two metres of flood in 2011.

Ayutthaya month by month

January

The driest month of the year and the coolest, with nights that genuinely feel cool on the ride back. Almost nothing falls. This is the month the ground is hardest and the light is cleanest, and it is also when the day trips fill first.

February

Still dry, and two degrees warmer by day than January. Rain arrives only as the odd shower. Mornings stay comfortable, but by early afternoon the open ground is already asking for a hat.

March

The heat sets in properly and the nights stop cooling off. Rain is still light. From this month on, plan the temples for the first hours after opening and put lunch in the middle of the day.

April

The hottest month, averaging 35.9°C by day on ground with no shade. Songkran falls mid-month and the country travels, so roads and temples are both busier. If you come now, a vehicle with air conditioning stops being a luxury.

May

The southwest monsoon arrives and the rainfall jumps from 68 mm to 208 mm. Days are a degree cooler than April and the light is more interesting. Showers are heavy and short rather than all-day, so a wet month is not a lost one.

June

Wet and a little cooler, with 223 mm across the month. The park is green rather than bleached, which suits photographs of brick. Afternoon storms are the pattern, so front-load the day.

July

A slight dip in the rain and the most comfortable of the wet months by temperature. The crowds are thinner than in the cool season. Take something waterproof for the camera rather than for yourself.

August

The wettest month of the year at 260 mm, and among the coolest by day. Rivers run high. Nothing here closes for rain, but this is the month when the water in the landscape is part of what you are looking at.

September

Still very wet, with the rivers at their fullest. The 2011 floods that put Wat Chaiwatthanaram under two metres of water peaked in the weeks after this. Check conditions if the season has been heavy.

October

The monsoon eases through the month and the ground begins to dry. Nights start cooling again. By the last week it often feels like the beginning of the good season rather than the end of the bad one.

November

Rain drops to 37 mm and the cool season starts. Loy Krathong falls this month and the rivers fill with floating lights, which is the one night of the year the water here is the attraction. Book earlier than you would otherwise.

December

Effectively no rain at all and the coolest days of the year at 30.0°C. Nights drop to around 17°C. It is the easiest month to spend a whole day walking, and the busiest for exactly that reason.

The seasons, and which one you want

Cool and dry, November to February. Highs from 30.0 to 33.3°C, nights down to 17°C, and almost no rain. This is the season to come if you want to walk the whole island, and it is the season everybody else wants too.

Hot and dry, March to May. The peak of the heat, with rain building through May. Come now and shape the day around the morning, or take a day that keeps you in a vehicle between temples.

Wet, June to October. Cooler by day than April, green underfoot, and far fewer people. August is the wettest at 260 mm. Rivers run high from August to October, which is when the boat itineraries are at their best and also when a heavy season is worth checking on.

Best time of day

The first two hours after the temples open are the best of the day in every month: the brick takes the low light, the ground has not begun to radiate heat back at you, and the coach parties from Bangkok have not yet arrived, because they cannot — they are still ninety minutes down the road.

The last hour before closing is the other one, and it is when the west bank comes into its own. That is the hour Wat Chaiwatthanaram is built for, and it is why the sunset itineraries end there rather than start there.

Frequently asked questions