Monthly weather averages & travel planning

Asia › 🇹🇭 Thailand › Chiang Mai
Updated: March 2026
May is a avoid time to visit Chiang Mai (3/10). With 10 daily sunshine hours and only 14 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 5th sunniest of the year in Chiang Mai. May suits travellers visiting for indoor culture, food, and architecture rather than outdoor activities. Pack accordingly for 14 potential rain days. June offers a similar profile at lower hotel rates if dates are flexible. The intense midday heat between noon and 4pm warrants strategic planning: front-load outdoor sightseeing before 11am, retreat indoors during peak heat, and resume in the late afternoon when temperatures ease. Planning tips: most accommodation categories have availability, and last-minute deals are common. The quieter streets and shorter queues can make this a genuinely enjoyable time to visit for the right type of traveller. Budget-conscious visitors will find the best value of the year in this period.
Chiang Mai's May climate peaks at 33°C each afternoon before cooling to 24°C overnight. 10 daily sunshine hours and just 14 wet days mean the odds of a fine day are solidly in your favour. It is a reasonable time to visit, with a backup plan for the occasional shower.
33°C
91°F
Avg High
24°C
75°F
Avg Low
14 days
109 mm total
Rain Days
10h
per day avg
Sunshine
78%
Humid
Humidity
The 9°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. At 78% humidity, the 33°C daytime high feels 2-4°C warmer in practice: quick-dry fabrics and shade-seeking between noon and 3pm are the sensible response. UV index averages 9 this month, classed as high to very high. SPF 30+ sunscreen, a brim hat, and sunglasses are not optional between 10am and 4pm. Winds are calm at an average 10 km/h, so wind-chill is not a factor in planning your clothing. In Fahrenheit: 91°F average high, 75°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Packing for Chiang Mai in May means dressing for 33°C days and 24°C evenings. A lightweight linen or cotton shirt with loose-fit trousers or a sundress handles the 33°C daytime heat. Evening temperatures settle at 24°C, a modest 9°C drop that a light cardigan or denim jacket covers. For footwear, breathable walking sandals work for casual exploration, but closed-toe trainers are better for uneven surfaces in the historic centre. With 14 rain days expected, a compact travel umbrella is worth the bag space. A waterproof jacket is better than an umbrella if you plan full-day outdoor routes. For temple and religious site visits, carry a lightweight scarf or sarong to cover shoulders and knees, required at most major sites across the region. At 78% average humidity, quick-dry synthetic or bamboo fabrics dry overnight and stay comfortable longer than cotton.
Local tip: Loose-weave linen and moisture-wicking fabrics are the practical choice in Chiang Mai's heat and humidity. Many shopping centres run air conditioning at near-arctic levels, so a thin layer in your bag prevents discomfort indoors.
May has no major festivals or public holidays in Chiang Mai, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
Based on 33°C average highs and 14 rainy days
In May, Chiang Mai sits in the dry season corridor, as the ITCZ shifts away from the region and trade winds bring drier, more stable air. This produces reliably sunny days reaching 33°C, with lower humidity than the wet months. Overnight lows of 24°C offer a pleasant reprieve from the midday heat. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate, wear sunscreen. UV 6-7: High, hat and SPF 30+ essential. UV 8-10: Very High, limit midday exposure. UV 11+: Extreme, seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry, skin and throat may feel parched. 40-60%: Comfortable, ideal for most people. 60-80%: Sticky, light breathable fabrics recommended. Above 80%: Muggy, heat feels more intense; quick-dry clothing is essential.
Chiang Mai in May
May ranks 5th sunniest of the year in Chiang Mai, with an average 10 daily sunshine hours. The driest months are January, February, and March. April is the hottest month (36°C avg high); December is the coolest (27°C). From here, temperatures fall 2°C into June. Compared to last month (April: 36°C high, 5 rain days), May is cooler and wetter. May sits in the middle of the annual sunshine ranking for Chiang Mai, offering a reasonable balance of good weather and manageable crowds.
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 28°C | 16°C | 1 | 10h | View |
| February | 31°C | 18°C | 1 | 11h | View |
| March | 34°C | 21°C | 2 | 11h | View |
| April | 36°C | 24°C | 5 | 11h | View |
| May | 33°C | 24°C | 14 | 10h | View |
| June | 31°C | 24°C | 20 | 9h | View |
| July | 30°C | 24°C | 23 | 7h | View |
| August | 29°C | 23°C | 25 | 7h | View |
| September | 29°C | 23°C | 24 | 8h | View |
| October | 29°C | 21°C | 16 | 10h | View |
| November | 28°C | 18°C | 4 | 10h | View |
| December | 27°C | 16°C | 2 | 10h | View |
January
1 rain days, 10h sun
February
1 rain days, 11h sun
March
2 rain days, 11h sun
April
5 rain days, 11h sun
May
14 rain days, 10h sun
June
20 rain days, 9h sun
July
23 rain days, 7h sun
August
25 rain days, 7h sun
September
24 rain days, 8h sun
October
16 rain days, 10h sun
November
4 rain days, 10h sun
December
2 rain days, 10h sun
Cities within 500 km with comparable weather conditions
Data Sources for Chiang Mai
Climate normals represent 30-year averages (1991-2020). Individual years may vary.