UV Index in Chiang Mai, Thailand

Last updated: May 3, 2025

In Chiang Mai, Thailand, being aware of the UV Index is crucial for protecting your skin from harmful ultraviolet rays. Understanding UV levels is essential not only for preventing painful sunburns but also for maintaining long-term skin health. With a tropical savanna climate, Chiang Mai experiences significant UV exposure, particularly during the midday hours when the index can soar to 14. By staying informed about the UV Index, you can take proactive measures to shield yourself from the sun’s harmful effects, ensuring a safe and enjoyable experience in this beautiful city.

Hourly UV Index in Chiang Mai

As the sun rises, the UV Index starts off low at 1 by 7:00 AM, gradually climbing to a moderate 3 by 8:00 AM. However, by 9:00 AM, it takes a sharp leap to 6, signaling that sun protection should be considered. The peak intensity occurs at 12:00 PM, hitting a striking 14, where the sun’s rays are most potent and precautions are essential. The afternoon sees a slight decline, dropping to 11 by 2:00 PM, before further retreating to 8 at 3:00 PM. As the day winds down, the index decreases steadily, settling at 1 by 6:00 PM and fading to 0 by 7:00 PM. This data highlights the importance of staying vigilant during peak hours to protect yourself from harmful UV exposure.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
Time	UVI	Category	Time to Burn
07:00	1	low	45 min
08:00	3	moderate	30 min
09:00	6	high	25 min
10:00	10	very high	15 min
11:00	13	extreme	10 min
12:00	14	extreme	10 min
13:00	14	extreme	10 min
14:00	11	extreme	10 min
15:00	8	very high	15 min
16:00	4	moderate	30 min
17:00	2	low	45 min
18:00	1	low	45 min
19:00	0	low	45 min

Monthly UV Index Trends in Chiang Mai

Throughout the year, UV Index levels exhibit significant seasonal variation, with the highest values observed from March to October. During this period, the UV Index peaks at 14, categorized as extreme from May to September, where the recommended maximum sun exposure is only 10 minutes before burns can occur. January and February start with a very high rating of 9 and 10, respectively, allowing for a slightly longer burn time of 15 minutes. Notably, the months of March, April, and October transition back to extreme but still maintain 10 minutes of safe exposure. For residents and visitors, it is crucial to take protective measures, especially during the high-risk months from March to October. Recommendations include wearing broad-spectrum sunscreen, protective clothing, and seeking shade during peak sun hours to minimize the risk of skin damage.

Monthly Maximum UV Index for Chiang Mai, Thailand

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Chiang Mai. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Chiang Mai, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare Chiang Mai UV Index with Other Thailand Cities

The table above highlights how UV exposure in Chiang Mai compares to other major locations across Thailand. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

Chiang Mai's solar exposure compared to other cities in Thailand. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Mueang Nonthaburi UVI	10	12	14	13	14	13	14	14	13	12	9	8
Samut Prakan UVI	10	12	14	13	14	13	14	14	13	12	9	8
Bangkok UVI	10	12	14	13	14	13	14	14	13	12	9	8
Chiang Mai	9	10	13	13	14	14	14	14	14	13	10	8
Udon Thani UVI	9	11	13	14	14	13	14	14	14	12	10	9
Chon Buri UVI	10	13	14	14	14	13	14	14	13	13	10	9