Summer in Chiang Rai feels like a blend of heat, humidity, and heavy rainfall that really shapes your time in the city. Daytime highs usually hit around 31–32°C (88–90°F), and afternoon showers are a regular part of the monsoon season.
Nights don’t cool off much, staying in the mid-70s°F, so the air keeps that warm, sticky feeling even after dark.
Rain falls often, but it doesn’t mean you’ll never see the sun. The sky can shift fast—maybe you wake up to clouds, then catch a burst of sunlight before another downpour rolls in.
Humidity hovers above 80%. That makes the heat feel even more intense, and honestly, it can make outdoor plans a bit tricky.
If you get a handle on how the weather works this time of year, you’ll plan smarter. Whether you’re after cultural sites, outdoor markets, or a hike in the mountains, knowing what to expect with temperature, rainfall, and daylight hours can really help.
Overview of Chiang Rai’s Summer Climate
Chiang Rai’s summer weather comes from its northern spot, moderate elevation, and a tropical wet and dry climate. Expect high humidity, frequent rainfall, and warm temperatures that barely budge all season.
These conditions really affect how comfy you’ll feel outside and when travel feels most enjoyable.
Geographical Location and Elevation
Chiang Rai sits way up in northern Thailand, close to Laos and Myanmar. The city is about 395 meters (1,296 feet) above sea level.
This elevation helps keep things a little cooler than in the lowlands, but it doesn’t stop the rain.
During summer, daily highs usually reach 31°C to 32°C (88°F to 90°F). Nights stay warm, averaging around 23°C (73°F).
The mountains around Chiang Rai shape the weather, too. Moist air from the southwest monsoon climbs over the hills, which leads to frequent rain showers and thunderstorms.
That’s why Chiang Rai gets some of the heaviest summer rainfall in northern Thailand.
Because of where the city sits and its elevation, expect humid, cloudy days with not much sunshine. The mix of altitude and seasonal winds makes the climate more unpredictable than in central or southern Thailand.
Tropical Wet and Dry Climate Characteristics
Chiang Rai has a tropical wet and dry climate (Köppen Aw), so the rainy and dry seasons feel very different. Summer lands right in the wet period, running from June through August.
Rainfall gets intense, with monthly averages from 178 mm (7 in) in June to over 350 mm (14 in) in August.
You’ll see a lot of overcast skies, and sunshine drops to about 5 hours a day.
Humidity climbs to 80–84%, making the air feel thick. That, plus the heat, can make outdoor sightseeing a sweaty challenge.
On the upside, all that rain brings lush greenery and slightly cooler evenings compared to the scorching spring months.
Unlike the dry season, with clear skies and barely any rain, the summer monsoon dominates. It brings plenty of water for agriculture, but you’ll need to plan for wet conditions and maybe some travel delays.
Typical Summer Temperature Patterns
Summer in Chiang Rai stays warm and steady, with just minor changes from month to month. High humidity sticks around, pairing with daytime heat, while nights are a bit more comfortable.
Average Daily Highs and Lows
From June through August, high temperatures usually sit between 31°C (88°F) and 32°C (90°F). The range doesn’t shift much, so you won’t get many surprises.
Low temperatures at night average around 23°C to 24°C (73°F–75°F). The mornings often feel heavy and humid since the nights don’t bring much relief.
The summer climate here isn’t as extreme as in central or southern Thailand. But, the combo of heat and rain can make it feel warmer than the numbers suggest.
Temperature Trends by Month
June kicks off with highs near 32°C (89°F) and lows around 24°C (75°F). Rain picks up fast, so the air stays damp even when the sun peeks out.
July cools just a bit, with highs around 31°C (88°F). Nights hold steady at about 23°C (74°F).
This month usually brings the most rain, so sunshine gets even scarcer.
August keeps the pattern going, with highs around 31°C (88°F) and lows near 23°C (74°F). Humidity peaks now, often hitting 80–84%, so outdoor stuff can feel extra tiring.
Daytime vs. Nighttime Temperatures
During the day, the heat feels even stronger because of the humidity and cloud cover. Even if the temperature isn’t sky-high, the air feels heavy and warm.
At night, temperatures drop just a little, settling in the mid-20s °C (low to mid-70s °F). Evenings are still warm, but at least they’re a bit easier to handle than the afternoons.
The difference between day and night temperatures, or the diurnal range, shrinks in summer. This limited cooling is one reason summer feels so consistently muggy in Chiang Rai.
Rainfall and Precipitation During Summer
Summer in Chiang Rai means some of the heaviest rainfall all year. Frequent showers and high humidity are the norm, and rainfall can swing a lot from month to month.
Monthly Rainfall Totals
Rainfall really ramps up in summer. June, July, and August each get well over 200 mm of rain, and August often tops out at 350–370 mm.
The monsoon season pulls in moist air, so you end up with wet conditions that shape daily routines and travel plans.
February, for comparison, only averages about 14 mm. Once summer hits, the difference is huge—outdoor plans get trickier.
| Month | Average Rainfall (mm) |
|---|---|
| June | ~250–300 |
| July | ~300–330 |
| August | ~350–370 |
Frequency of Rainy Days
It’s not just about how much it rains—it’s how often. In summer, you’ll see 18–23 rainy days per month.
Most days bring at least some rain, though it doesn’t usually last all day.
Rain comes in short, intense bursts, mostly in the afternoon or evening. Your best shot at dry weather is in the mornings.
Compared to the dry season, where you might get only a couple of rainy days, summer’s a different world. This regular rain keeps the soil wet and the scenery green.
Seasonal Changes in Precipitation
When summer starts, it’s a clear shift from dry to wet. Rainfall climbs quickly starting in May, peaking in August, then slowly drops off by October.
The Southwest Monsoon brings in moist air from the Indian Ocean, so rainfall gets heavier and lasts longer.
Humidity shoots up too, often reaching 80–84%. The combo of frequent rain and high humidity creates the damp, sticky environment that defines Chiang Rai’s summer.
Humidity and Dew Point
Summer in Chiang Rai brings high moisture levels that really affect comfort and outdoor plans. You’ll notice not just higher relative humidity, but dew points that make the air feel warmer and heavier than the thermometer suggests.
Average Relative Humidity
From June through August, relative humidity typically ranges from 80% to 84%. These are some of the highest levels all year.
Frequent rain and warm air keep more moisture trapped, so the air often feels thick and sticky.
Mornings usually start off with humidity above 80%. As the day heats up, it might drop a little but rarely dips below 70%.
Even on drier afternoons, the air holds plenty of moisture.
Compared to the dry season—when humidity can drop to 62% in March—the difference is pretty clear. Expect damp conditions, especially if you’re out walking or hiking for a while.
If you’re traveling, this high humidity can make drying clothes tough, sleeping less comfortable, and even being indoors can feel stuffy without good ventilation or AC.
Dew Point Fluctuations
The dew point in Chiang Rai during summer usually stays between 22°C and 24°C (72°F–75°F). That’s high, and it means the air’s packed with water vapor.
When the dew point goes above 22°C, you’ll notice the air feels muggy and not very refreshing.
Unlike relative humidity, which changes with the temperature, the dew point gives a more honest sense of how sticky it feels.
Even if the temperature drops a little, a high dew point keeps things feeling clammy.
At night, dew points stay up, so evenings don’t cool off much. Sleeping without a fan or AC isn’t exactly easy.
For outdoor stuff, a high dew point makes it harder for your body to cool off by sweating. You’ll probably tire out faster, so plan for breaks in the shade or somewhere with AC.
Wind Conditions in Summer
In summer, Chiang Rai’s winds stay light to moderate and mostly follow the monsoon pattern. Speed and direction can shift as rainfall picks up, which might affect how comfortable it feels outside.
Average Wind Speed
Wind speeds here are usually modest, especially compared to Thailand’s coast. Most days, you’ll get breezes of 5 to 10 km/h (3 to 6 mph).
These light winds don’t do much to cool things off, so the air often feels warmer with all the humidity.
Winds pick up a bit during heavy rain, especially in July and August when storms are more frequent. Gusts might reach 15 to 20 km/h (9 to 12 mph), but those bursts don’t last long.
Sustained strong winds are rare since Chiang Rai sits inland.
With so much moisture in the air and low wind speeds, humidity just hangs around. Most people end up relying on shade or indoor cooling instead of breezes.
Prevailing Wind Direction
Summer winds in Chiang Rai mostly follow the southwest monsoon. Air moves in from the Indian Ocean toward northern Thailand, bringing lots of moisture.
This southwest flow runs from June through August and explains why the months are so rainy.
Sometimes, the hills around Chiang Rai nudge the wind a bit to the west or south, especially during storms. These shifts don’t last long.
You won’t see much of the strong northerly winds in summer—those show up in the cooler dry season. The steady southwest breeze is what really shapes the summer climate here.
Sunlight and Daylight Hours
Chiang Rai’s summer means long days, heavy humidity, and lots of cloud cover. The difference between the bright late spring and the dimmer, rainier mid-summer becomes pretty obvious.
Average Hours of Sunshine
Sunshine in Chiang Rai really changes a lot between early and late summer. March stands out as the sunniest month, with an average of 9.8 hours of sunshine per day.
But by August, thick clouds roll in and sunlight drops to just 3.9 hours daily.
If you look at the whole year, Chiang Rai gets about 2,555 total sunshine hours. That puts it somewhere between bright cities like Lisbon and places with more gray days, like Manchester.
During summer, you’ll notice a clear pattern. The closer August gets, the more the rainy season takes over, and the less sun you’ll see.
Here’s a quick look at the numbers:
| Month | Avg. Daily Sunshine | Total Monthly Hours |
|---|---|---|
| March | 9.8 hrs | ~295 hrs |
| June | ~5.5 hrs | ~165 hrs |
| August | 3.9 hrs | ~117 hrs |
So, if you’re hoping for lots of sun for your outdoor plans, keep in mind that afternoons can get cloudy or rainy, especially as summer goes on.
Sunrise and Sunset Times
Daylight in Chiang Rai shifts gradually throughout the year, thanks to its tropical latitude. In summer, days usually stretch between 12.5 and 13.3 hours.
Late June brings the longest day, with about 13 hours 20 minutes of daylight. July and August feel just a bit shorter.
You’ll probably catch summer sunrises around 5:40–6:00 AM. Sunsets drop in between 6:45–7:00 PM.
Even when rain clouds cut back on sunshine, you still get plenty of daylight to work with. The steady day length lets you plan early morning or evening activities and count on having enough light, even if it’s pouring.