Udon Thani and the Isan region has a tropical savanna climate with three seasons: Winter, Summer and Rainy Season. Each season has its own unique character, mood, colour and food. Winter is generally mild, dry, cold enough to require jumpers, and has wonderfully beautiful misty mornings. Summer is hot with modest rain and the highest annual temperatures, peaking around April. The rainy season sees lower temperatures than summer but the highest levels of rain, with the wettest months being August and September. Across the year temperatures can range from as low as 5c in winter to as high as 40c in summer.

The approximate dates for each season are: Summer, February to May. Rainy Season, May to October. Winter, October to February. For trip planning purposes, you can find monthly averages and the ten day forecast on our 10 Day Weather Forecast page.

Sea fog sunrise over the Mekong River — Misty sunrise over the Mekong River on a winter's morning

Best Time to Visit: October – February

There is never a bad time to visit Udon Thani as each season has its own special charms. Most people, this author included, feel the best time to visit is during winter, with mild temperatures, stunning misty mornings and rain-free days — ideal for outdoor activities from camping to hiking to sightseeing. For some, however, winter is too cold for swimming in outdoor pools or lakes.

An early January morning trip to the glass skywalk at Wat Pha Tak Suea can reveal breathtaking views of morning mist rolling across the Mekong Valley. Winter is also the best time to visit Red Lotus Lake, as this is when the lilies bloom, and the best time to enjoy trips to Phu Phra Bat Historical Park and Erawan Cave when lower temperatures are more amiable for long walks and steep climbs.

Fruits that come into season during winter include strawberries, melons, pomegranates, tamarind and rose apples. Deliciously spicy Isan soups and salads provide delightful warmth after an early morning outside. Winter is also a joyous time in Udon Thani, with many concerts and firework shows around the New Year.

Winter in Udon Thani is marvellous and highly recommended. Do come prepared with light jumpers for warmth, and gloves to protect your hands if planning to drive a scooter.

Woman standing on a mountain looking at a misty morning valley — In winter, the Udon Thani landscape is transformed with mesmerising misty mornings

Summer Season: Water Fun Time

Summer in Udon Thani is about water fun, as people look to escape the hot days. Typically arriving between the end of February and start of March, it brings rising temperatures that peak during April, reaching highs in the 30s and even occasionally low 40s, with often limited rain and droughts that can last well into May or June.

The summer heat peaks in April just in time for Songkran, which has grown into a three day festival that absorbs the whole of Udon Thani into one huge, city-wide water fight. Water parks such as Usotel Waterland are full of families enjoying themselves, and hiring a raft on Nam Pan Lake has recently become a very popular way to spend a day. For food lovers, mangos ripen between March and June, and most ice cream parlours run special mango promotions.

Two young children getting their water pistols ready for Songkran — Summer is the perfect time for water fun, especially around Songkran

Rainy Season: One Huge Gulp of Water

In the rainy season it rains, a lot — but these rains are essential for the region. They fill the reservoirs for the year ahead, fuel the Mekong River and its hydroelectric dams, and fill the rice fields. Isan is at its most beautiful at this time of year, with nature flourishing and the whole region turning into an endless sea of green as the rice plants race skywards. The storms also bring stunning evening skylines and surreal sunsets.

Typically the rains don't arrive in Udon Thani until May or June. Udon Thani's inland location and distance from the Indian Ocean means these storms have weakened considerably by the time they arrive, though rain can still be intense with heavy downpours, thunder and lightning. The months with the highest rainfall are August and September, when it will rain roughly two out of three days, though rarely all day.

It can flood suddenly during these months, though improved drainage and irrigation systems mean this happens less often. People generally carry on regardless of the rain — it's just part of life.

Monsoon rains over a Thailand province — Monsoon rains over Thailand province

Winter Season: Glorious Misty Mornings

Winter arrives in Udon Thani around mid October, always welcomed after the heat of summer and the rain of the monsoon. It announces itself with dry sunny days and a drop in temperature, especially in the mornings. Mean temperatures mellow to the mid twenties in October and drop further to the low twenties in December and January. Still clean and fresh from the rainy season, the rice fields gleam in colour as the rice starts to ripen.

As November turns to December, the fields lose their greenness as the rice is harvested and the land ploughed. Days are rain-free and morning temperatures can drop below 10c, meaning jumpers are required — but mornings are covered in mist, creating stunning sunrises across the landscape. For a real treat, head to the mountains around the Mekong River or the Red Lotus Lake for truly divine, magical morning scenes.