Weather in Koh Samui 🇹🇭
Monthly weather averages & travel planning
March
Avg Temp
26°C
Rain Days
10 days
Sun Hours
11 hrs
Humidity
82%
Asia › 🇹🇭 Thailand › Koh Samui
Updated: March 2026
Is March a Good Time to Visit Koh Samui?
6/10
Good
March is a good time to visit Koh Samui (6/10). With 11 daily sunshine hours and only 10 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 3rd sunniest of the year in Koh Samui. Culture-focused travellers and those who prefer lighter crowds will find March a practical choice, with prices running lower than peak January without sacrificing all the good weather. April offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Koh Samui's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.
vs February:25°C avg high
Step off the plane in Koh Samui in March and the air meets you at around 26°C, a temperature that feels genuinely welcoming after a long flight. By the time evening arrives and temperatures settle near 24°C, the city takes on a different character entirely. With 11 hours of daylight sun on offer, March gives you the raw material for a genuinely memorable trip.
26°C
79°F
Avg High
24°C
75°F
Avg Low
10 days
89 mm total
Rain Days
11h
per day avg
Sunshine
82%
Humid
Humidity
Temperature in Koh Samui in March
The narrow 2°C gap between daytime and overnight temperatures, characteristic of coastal cities with maritime moderation, means a single mid-layer works across the whole day. At 82% humidity, the 26°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 6 this month, classed as moderate. Sunscreen is a sensible precaution for extended outdoor time, particularly at midday. Wind averages 20 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 79°F average high, 75°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Temperature Trends
High
Low
Rainfall (mm)
0-20 mm21-50 mm51-100 mm100+ mm
What to Wear in Koh Samui in March
Morning24°CBefore the day warms up
Afternoon26°CPeak daytime temperature
Evening27°CAfter sunset cools down
Packing for Koh Samui in March means dressing for 26°C days and 24°C evenings. A light cotton tee with a casual overshirt works well at 26°C, the overshirt doubles as a layer for air-conditioned venues. Evening temperatures settle at 24°C, a modest 2°C drop that a light cardigan or denim jacket covers. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues. A compact foldable umbrella weighs almost nothing and earns its keep across 10 potential rainy days. 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 82% average humidity, quick-dry synthetic or bamboo fabrics dry overnight and stay comfortable longer than cotton.
Local tip: Temple and religious site visits require covered shoulders and knees in most of Koh Samui's heritage areas. A lightweight scarf or sarong weighs almost nothing and solves the problem instantly.
Events in Koh Samui in March
March has no major festivals or public holidays in Koh Samui, 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.
What to Pack for Koh Samui in March
Based on 26°C average highs and 10 rainy days
- Light layers for morning and evening
- Breathable T-shirts and comfortable trousers
- UV-protective sunglasses
- Quick-dry travel towel
- Anti-chafe balm for long walking days
- Moisture-wicking synthetic fabrics for active days
- Compact folding umbrella
- Waterproof outer layer or packable rain jacket
- Quick-dry clothing that recovers fast after a shower
- SPF 30+ sunscreen
- Comfortable walking shoes (a second pair lets the first air out overnight)
- Universal travel adapter
- Small day pack for city exploration
- Reusable water bottle
Best Activities in Koh Samui in March
- Explore outdoor markets and street food stallsMid-morning (10am-12pm)At 26°C, the temperature is ideal for extended walking without overheating
- Guided walking tour of the historic centreMorning or late afternoonComfortable temperatures allow several hours on foot without fatigue
- Visit rooftop viewpoints and observation decksGolden hour (1 hour before sunset)Warm clear evenings provide exceptional visibility for panoramic photography
- Day trip to the surrounding countryside or coastFull day (depart by 8am)March is reliably dry enough for rural day trips without weather risk
- Afternoon in a world-class museum or galleryAfternoon (2-5pm)Pairs well with outdoor morning activities and provides a mid-day rest from sightseeing
- Coffee-house or traditional cafe culture experienceMid-morning or post-lunchA cultural ritual in this region that rewards slow appreciation regardless of weather
- Evening live music, theatre, or opera performanceEvening shows typically at 7-9pmConsistent evening temperatures make getting to and from evening venues comfortable
- Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningMarch brings distinct seasonal changes to public green spaces worth exploring
- Seek out chilled local specialities: cold-brew tea, ice desserts, or chilled seafood at street-level stallsAny time; most atmospheric in evening marketsHot-weather street food culture peaks in March, with vendors setting up specifically for warm evenings
Why is Koh Samui warm in March?
In March, Koh Samui 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 26°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.
Frequently Asked Questions
Koh Samui in March
In March, Koh Samui experiences average highs of 26°C (79°F) and lows of 24°C (75°F). Expect around 10 rainy days and 11 hours of sunshine per day, with humidity averaging 82%. The 2°C gap between daytime and overnight temperatures is worth planning around: light layers work for most visitors during the day, but an overshirt or cardigan handles the cooler evenings. UV index averages 6, so sun protection is advisable on clear days.
Koh Samui typically sees 10 rainy days in March, with total precipitation of around 89mm. Rain is moderate and manageable. Showers tend to pass quickly, and a light rain layer or foldable umbrella is sufficient protection for most days. For context, the driest month in Koh Samui typically sees 4-6 fewer rain days than March.
Pack light layers, a light jacket for evenings, comfortable walking shoes, and sunscreen for Koh Samui in March. Daytime temperatures of 26°C are pleasant, but the evening drop to 24°C means a jacket is essential if you plan to be out after dark. With 10 rainy days, bring a compact umbrella or waterproof jacket for unexpected showers. Comfortable walking shoes are a priority given the amount of ground most visitors cover.
Yes, March is an excellent time to visit Koh Samui. With 11 daily sunshine hours and only 10 rainy days, conditions are ideal for sightseeing and outdoor activities. Temperatures averaging 26°C during the day are comfortable for long walks and outdoor dining. This is peak travel season, so booking accommodation in advance and arriving at popular attractions early in the morning helps avoid the busiest periods.
The average high temperature in Koh Samui in March is 26°C (79°F), and the average low is 24°C (75°F). The mean daily temperature is approximately 25°C (77°F). The day-to-night range of 2°C is narrow, typical of coastal or maritime cities. These are 30-year climate normals based on the 1991 to 2020 reference period; individual years will vary, particularly in transitional months like spring and autumn.
The best month to visit Koh Samui is generally January. January offers the most sunshine at 11 hours per day and only 11 rainy days. Average temperatures reach 25°C, making it comfortable for sightseeing, outdoor dining, and exploring the city. If your travel dates are flexible, planning your trip around January gives you the best chance of dry, bright weather.
March is shoulder or low season in Koh Samui, meaning fewer tourists and generally lower prices than peak months. With 11 sunshine hours and 10 rainy days, the weather is less of a draw for mass tourism. This is an advantage for travellers who prefer a quieter, more relaxed experience with shorter queues and easier accommodation availability.
In March, Koh Samui suits a range of activities thanks to mild temperatures around 26°C. Mix of indoor and outdoor activities works well given the moderate chance of rain. Top options include exploring historic neighbourhoods, visiting museums and galleries, local food markets, and day trips to surrounding areas. With 11 hours of sunshine, parks and waterfront walks are particularly enjoyable.
March ranks 3rd sunniest of the year in Koh Samui, with an average 11 daily sunshine hours. The driest months are February, March, and January. April is the hottest month (27°C avg high); January is the coolest (25°C). From here, temperatures rise 1°C into April. Compared to last month (February: 25°C high, 6 rain days), March is warmer and wetter. March is among the top three sunniest months to visit Koh Samui.
Year-Round Climate
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 25°C | 23°C | 11 | 11h | View |
| February | 25°C | 23°C | 6 | 11h | View |
| March | 26°C | 24°C | 10 | 11h | View |
| April | 27°C | 24°C | 12 | 11h | View |
| May | 27°C | 24°C | 22 | 11h | View |
| June | 27°C | 24°C | 19 | 10h | View |
| July | 27°C | 24°C | 18 | 10h | View |
| August | 27°C | 24°C | 18 | 10h | View |
| September | 26°C | 23°C | 22 | 9h | View |
| October | 25°C | 23°C | 26 | 9h | View |
| November | 25°C | 23°C | 22 | 9h | View |
| December | 25°C | 23°C | 14 | 10h | View |
January
11 rain days, 11h sun
25°23°
February
6 rain days, 11h sun
25°23°
March
10 rain days, 11h sun
26°24°
April
12 rain days, 11h sun
27°24°
May
22 rain days, 11h sun
27°24°
June
19 rain days, 10h sun
27°24°
July
18 rain days, 10h sun
27°24°
August
18 rain days, 10h sun
27°24°
September
22 rain days, 9h sun
26°23°
October
26 rain days, 9h sun
25°23°
November
22 rain days, 9h sun
25°23°
December
14 rain days, 10h sun
25°23°
Other Months in Koh Samui
Plan Your Trip to Koh Samui
Nearby Destinations
Cities within 500 km with comparable weather conditions
Data Sources for Koh Samui
Climate normals represent 30-year averages (1991-2020). Individual years may vary.