The short answer: November to February
If you would like the simplest possible recommendation, here it is: the best time to visit Thailand is during the cool, dry season, which runs from November to February. These are the most comfortable months of the year, with warm but manageable daytime temperatures, low humidity by Thai standards, clear skies and very little rain across most of the country.
This is also, unsurprisingly, the peak tourist season, so you will be sharing the headline sights with rather more visitors and paying a little more for hotels and flights, especially over Christmas and the New Year. We think the trade-off is well worth it. For most travellers, and particularly for those in their sixties and beyond, the sheer comfort of touring in pleasant, dry weather more than makes up for the slightly busier streets.
The cool season in detail (November to February)
During the cool season, daytime temperatures in Bangkok and the central plains sit comfortably in the mid-twenties to high-twenties Celsius, with refreshing, drier air and pleasant evenings. It is the ideal weather for strolling around the Grand Palace, drifting along the canals or browsing a floating market without becoming uncomfortably hot and weary.
The north of the country, around Chiang Mai and the surrounding hills, is at its loveliest now. Mornings can be genuinely crisp and cool, sometimes calling for a light jumper or shawl at dawn, and the countryside is green and inviting after the rains. This is the classic season for visiting the temples, the elephant sanctuaries and the gentle hill scenery that the north does so well.
Down on the islands and along the coasts, the seas are calmer and the skies clearer, making this a glorious time for a few restful days by the water. Because this is the busiest stretch of the year, we always recommend booking well ahead so that the best hotels and the most considerate room locations, such as those near lifts and on lower floors, can be secured for you.
The hot season (March to May)
From March to May, Thailand becomes genuinely hot. Temperatures climb into the low thirties and beyond, and by April, the hottest month, the heat and humidity can feel quite draining, especially in the cities and during the middle of the day. It is still perfectly possible to travel and enjoy yourself, but it calls for a gentler, slower approach, plenty of rest in the shade and an air-conditioned coach for the longer journeys.
April brings Songkran, the Thai New Year, a joyful and exuberant water festival celebrated across the country in the middle of the month. Locals and visitors alike take to the streets with water pistols and buckets in a good-natured, drenching free-for-all that is great fun to witness. It is worth knowing in advance that you may well find yourself splashed, and that some shops and offices close over the holiday, so a little extra patience helps.
One important word of caution for the hot season concerns the north. Around March and into April, the region around Chiang Mai experiences what is locally known as the burning season, when agricultural fields are cleared and a persistent smoky haze can settle over the hills. Air quality can dip noticeably, the views are obscured and it can be uncomfortable for anyone with a chest or breathing condition. If you have your heart set on Chiang Mai, we would steer you away from these particular weeks.
The green season (June to October)
The rainy season, which the Thais rather more charmingly call the green season, runs roughly from June to October. It carries an unfair reputation. In practice, the rain rarely falls all day. It tends to arrive as a heavy, dramatic downpour in the late afternoon or evening, often lasting only an hour or two before clearing to leave the air washed clean and the landscape impossibly lush and green.
For the unhurried traveller who does not mind planning around an afternoon shower, the green season has genuine appeal. The crowds thin out considerably, the famous sights feel far more peaceful, and prices for hotels and flights fall to their most appealing of the year. The countryside is at its most verdant, the waterfalls are full and the photographs are wonderful.
There are sensible caveats. September and October tend to be the wettest months in many areas, occasional flooding can affect low-lying parts of Bangkok and the provinces, and the seas can be choppier. We would simply suggest keeping your itinerary a touch more flexible, carrying a light waterproof and a compact umbrella, and treating any rain as a welcome excuse to pause over a leisurely lunch.
Choosing the islands by season: Andaman versus Gulf
One of the quirks that catches many visitors out is that Thailand's two coastlines do not share the same weather, and choosing the right island for the time of year can make all the difference to your few days by the sea.
The Andaman coast, on the western side, takes in Phuket, Krabi and the much-photographed limestone bays. It is at its best from November to April, when the seas are calm, the skies are clear and conditions are ideal for boat trips and gentle days on the beach. Its rainy months fall in the middle of the year, broadly May to October, when the surf can be rougher.
The Gulf coast, on the eastern side, follows a slightly different and later pattern. Koh Samui and its neighbouring islands are generally driest and sunniest from around January to April, while their wettest spell comes later in the year, roughly October to December, just when the Andaman side is drying out. The practical upshot is reassuring: at almost any time of year there is a good Thai island somewhere enjoying fine weather, and we are always happy to point you towards the one that best suits your travel dates.
Thailand month by month at a glance
Here is a quick month-by-month summary based on Bangkok, with average daytime temperatures and how busy you can expect things to be. January, around 26 degrees, is cool, dry and peak season. February, around 27 degrees, is much the same, comfortable, dry and busy. March, around 29 degrees, marks the start of the hotter, shoulder-season months as the crowds begin to ease.
April, around 31 degrees, is the hottest month of the year and home to the Songkran festival; it is shoulder season and very warm indeed. May, around 30 degrees, is hot and noticeably quieter as the first rains arrive. June through to August, all around 29 degrees, fall in the green season, warm and humid with afternoon showers but pleasingly peaceful and good value.
September, around 28 degrees, and October, around 27 degrees, are the wettest of the green-season months, quiet and inexpensive but best approached with a flexible plan. November, around 26 degrees, ushers in the return of the cool, dry weather as shoulder season builds towards the peak. December, around 25 degrees, is the coolest and one of the most delightful months of all, firmly back in peak season with the festive period in full swing.
What this means for the over-60s
For the mature traveller, our guidance is straightforward: wherever possible, plan your Thailand holiday for the cool, dry season between November and February. The gentler temperatures and lower humidity make every part of the day more comfortable, from a morning at the temples to an evening stroll along the riverside, and they place far less strain on the body than the fierce heat of April.
Whatever month you choose, heat and humidity deserve respect. We build our itineraries around an air-conditioned coach, a sensible pace and a good deal of time to rest, so that you are never marched from sight to sight in the heat of the day. Staying well hydrated, seeking out the shade and taking the middle of the day a little more gently are simple habits that make all the difference.
A few words on packing. Light, loose, breathable cotton and linen clothing is ideal, along with a comfortable, supportive pair of shoes for temple courtyards and uneven paths. Do bring a hat, good sunglasses and a high-factor sun cream, a light layer for cool northern mornings and over-zealous hotel air-conditioning, and a compact umbrella if you are travelling in the green season. With a little forethought and a sensibly gentle pace, Thailand is a joy to explore at any age, and our escorted tours are designed to take the effort off your shoulders so that you can simply enjoy it.