July is the middle of the southwest monsoon. TMD describes a pause in the rains in the first half and abundant rain again in the second. Below are Thai Meteorological Department (TMD) normals for nine stations, what July 2026 looked like, sea safety, national park closures and the holidays that fall in July 2027. Checked on 25 October 2026.
July weather by region: TMD normals
These are 1991-2020 normals from the TMD report; the Krabi station (48 563) has a shorter 1994-2020 record. A rainy day means 0.1 mm or more. Khao Lak uses the nearest TMD station, Takua Pa (individual beaches may differ), Pattaya the Phatthaya station, Koh Chang the Trad station on the mainland. TMD has no stations on Koh Phangan or Koh Tao, so the Ko Samui station is the nearest reference for them.
| Region, TMD station | High, °C | Low, °C | Rain, mm | Rainy days | Hotel occupancy Jul 2025, % |
|---|---|---|---|---|---|
| Phuket (Phuket) | 32.3 | 25.6 | 240.2 | 19.1 | 70.68 |
| Khao Lak (nearest station Takua Pa) | 31.5 | 24.6 | 465.8 | 22.3 | 70.44 (Phang Nga) |
| Krabi (Krabi, 1994-2020) | 31.6 | 22.8 | 221.5 | 17.6 | 59.31 |
| Koh Samui (Ko Samui) | 32.3 | 25.1 | 117.0 | 14.3 | 76.47 (Surat Thani) |
| Pattaya (Phatthaya) | 31.6 | 26.2 | 103.6 | 12.7 | 76.04 (Chon Buri) |
| Hua Hin (Hua Hin) | 33.0 | 25.7 | 90.2 | 14.8 | 72.26 (Prachuap Khiri Khan) |
| Bangkok (Bangkok Metropolis) | 33.5 | 26.1 | 189.7 | 17.2 | 76.45 |
| Chiang Mai (Chiang Mai) | 32.1 | 24.3 | 148.6 | 18.8 | 58.19 |
| Koh Chang (nearest station Trad, mainland) | 30.7 | 24.0 | 1,024.1 | 26.6 | 44.84 (Trat) |
Hotel occupancy from the Ministry of Tourism and Sports (MOTS) is by province, not by resort. A normal is a 30-year average, and any single year can be much drier or wetter.
How July behaves: TMD’s description and July 2026
TMD’s 3-month outlook issued on 22 June 2026 describes July from the 30-year pattern. In the first half a dry spell often continues from late June, because the low-pressure trough sits over southern China and the southwest monsoon weakens, so many areas get little or no rain for several days in a row. In the second half the trough moves back over upper Thailand and the monsoon becomes more active again, with abundant rain. Some tropical cyclones may pass near the east of Thailand.
July 2026 as an example:
- rain across Thailand 8% above normal, with the east 37% above and the centre 14% below
- the western coast of the south 13% below normal and the Gulf coast of the south 5% below
- the lull in the middle of the month, when a high-pressure ridge covered the Andaman Sea and the south
- flooding in Phang Nga, Phuket and Krabi on 1 July, and in Phuket on 24-25 July
- average temperature 0.2 °C above normal
Where to go in July
Koh Samui, Koh Phangan, Koh Tao. The Samui station records 117.0 mm on 14.3 days, under half of Phuket’s. Surat Thani province was 76.5% full in July 2025, level with Bangkok at the top of the table. See the Koh Samui holiday guide.
Hua Hin and Pattaya. Hua Hin gets 90.2 mm on 14.8 days and Pattaya 103.6 mm on 12.7 days, the driest two stations in the table. Occupancy in 2025 was 72.3% in Prachuap Khiri Khan and 76.0% in Chon Buri.
Phuket, Krabi, Khao Lak. Phuket gets 240.2 mm on 19.1 days, Krabi 221.5 mm and Takua Pa 465.8 mm on 22.3 days. Expect surf on west-facing beaches. Details in Phuket in the rainy season.
Bangkok and Chiang Mai. Bangkok gets 189.7 mm on 17.2 days, Chiang Mai 148.6 mm on 18.8 days with highs of 32.1 °C. Chiang Mai hotels were 58.2% full in July 2025, the lowest month of that year for the province. See the Chiang Mai guide.
Koh Chang. July is the wettest month at the Trad station: 1,024.1 mm on 26.6 days. Trat province was 44.8% full in July 2025. See the Koh Chang guide.
Sea and swimming in July
TMD’s July summary says the southwest monsoon over the Andaman Sea, Thailand and the Gulf of Thailand was moderate to rather strong at times. Rawai municipality’s page on Nai Harn, which also mentions the neighbouring Ao Sane bay, says that in the monsoon season from May to October the waves are very strong and not suitable for swimming, and Karon municipality describes the waves at Karon Beach as fairly strong. TAT’s rule of thumb for flags: red means do not swim, yellow means medium risk, green means calm, and a red-yellow flag marks the area with lifeguards on duty. Boat trips run but can be cancelled at the last minute.
We have no official wave heights for July. What to do if a current pulls you out is in red flags and rip currents.
National parks and islands in July
The Department of National Parks (DNP) publishes a closure table for national parks every year. The 2026 table is dated 7 January 2026 and the 2027 table is not out yet, so these are 2026 dates; confirm with your operator before booking.
| Park and sites | Closed | Source |
|---|---|---|
| Mu Ko Similan National Park, all tourist sites | 16 May-14 October | DNP park page, 2026 table |
| Mu Ko Surin National Park, all tourist sites | 16 May-14 October | DNP 2026 table |
| Ko Rok, Hin Daeng and Hin Muang (Mu Ko Lanta National Park) | 16 May-15 November | DNP park page |
| Ko Cheuk and Ko Wan (Hat Chao Mai National Park) | 1 June-30 September | DNP 2026 table |
| Ko Adang, Ko Rawi and other listed islands (Tarutao National Park) | 1 June-30 September | DNP 2026 table |
| Bulon and Lao Liang islands (Mu Ko Phetra National Park) | 1 June-30 September | DNP 2026 table |
| Ao Khai Tao, giant mangrove and the Ko Chang (Ranong) campsite (Mu Ko Ranong National Park) | 1 May-31 October | DNP 2026 table |
| Khao Ra hiking trail on Koh Phangan (Than Sadet-Ko Pha-ngan National Park) | 15 May-15 November | DNP 2026 table |
| Doi Pui peak and campsite (Doi Suthep-Pui National Park, Chiang Mai) | 1 May-30 September | DNP 2026 table |
| Kio Mae Pan nature trail and Lan Sadet waterfall (Doi Inthanon National Park, Chiang Mai) | 1 June-31 October | DNP 2026 table |
| Tham Nam Thalu cave (Khao Sok National Park) | 1 June-30 November | DNP 2026 table |
Ang Thong Marine Park from Samui is open: its closure runs from 1 November to 15 December (Ang Thong).
Holidays and events in July
The Bank of Thailand (BOT) set the 2027 holidays for banks and financial institutions in Notification 37/2569, announced on 17 August 2026:
| Date | Holiday | Source |
|---|---|---|
| Sunday 18 July | Asarnha Bucha Day | Bank of Thailand |
| Monday 19 July | Substitute bank holiday for Asarnha Bucha. Khao Phansa, the start of Buddhist Lent, falls on the same day (day after the eighth-month full moon per TAT, our date arithmetic) | Bank of Thailand, TAT |
| Wednesday 28 July | King Maha Vajiralongkorn’s birthday | Bank of Thailand |
Festival dates move every year. TAT published its July 2026 calendar on 26 June 2026, and we found no July 2027 programme yet. For scale, TAT’s July 2026 calendar listed:
| Event | 2026 dates | Where | Source |
|---|---|---|---|
| Samui Story Fun Fest, Chaweng Square | 4-5 July | Surat Thani | TAT |
| Rinma Summer Beach, Cha-am to Hua Hin coast | 4 July | Phetchaburi | TAT |
| Tak Bat Dok Mai Khao Phansa | 27-30 July | Saraburi | TAT |
| Ubon Ratchathani Candle Festival | 28-30 July | Ubon Ratchathani | TAT |
Crowds and prices in July
We give no room prices: there is no official rate series, and we have not run our own dated price check yet. MOTS hotel occupancy by province in July 2025: Phuket 70.7% (January 86.4%), Phang Nga (Khao Lak) 70.4%, Krabi 59.3%, Surat Thani (Samui) 76.5%, Chon Buri (Pattaya) 76.0%, Prachuap Khiri Khan (Hua Hin) 72.3%, Bangkok 76.5%, Chiang Mai 58.2%. Occupancy is not a price, so check rates for your own dates.
Should you go to Thailand in July?
Yes for the Gulf side, for the cities and for the north, with the Buddhist holiday weekend in mind. Choose another month for the Similan and Surin Islands. The month before is Thailand in June, the month after is Thailand in August, and beaches by season are in Thailand beaches by month.
FAQ
Is July a good time to visit Thailand?
For the Gulf side and the cities, yes. TMD normals give Hua Hin 90 mm, Pattaya 104 mm and Samui 117 mm, against 240 mm at Phuket and 466 mm at Takua Pa. The Similan and Surin Islands are closed and surf is strong on the Andaman coast.
Is July the rainiest month in Thailand?
Not on most stations. The Trad station near Koh Chang has its wettest month in July (1,024.1 mm on 26.6 days), but Phuket, Bangkok and Khao Lak peak in August or September and Chiang Mai in August. Samui is far drier, 117.0 mm.
Is there a dry spell in July?
TMD's description of the usual pattern is a dry spell in the first half of July, often continuing from late June, with many areas getting little or no rain for several days, and abundant rain again in the second half. In July 2026 the lull came in the middle of the month, when a high-pressure ridge covered the Andaman Sea and the south. Even so, Phuket was flooded on 1 July and on 24-25 July.
When is Khao Phansa in 2027?
TAT says Khao Phansa, the first day of Buddhist Lent, falls on the day after the full moon of the eighth lunar month. The Bank of Thailand lists Asarnha Bucha on Sunday 18 July 2027, so Khao Phansa is Monday 19 July by our arithmetic. Banks are closed that Monday as the substitute day.
Is the King's Birthday a holiday in Thailand?
Yes. The Bank of Thailand's 2027 list gives Wednesday 28 July as the birthday of King Maha Vajiralongkorn and a bank holiday. Check opening hours of offices for the day.
Is Phuket worth visiting in July?
Only if you accept surf and showers: 240.2 mm on 19.1 days. Hotel occupancy in the province was 70.7% in July 2025 against 86.4% in January. The Similan Islands are closed and the DNP park page closes Ko Rok, Hin Daeng and Hin Muang until 15 November.
Is the air clean in the south in July?
The Pollution Control Department's regional office 14 lists July to September as the PM2.5 watch period for the south, with traffic, burning, industry and cross-border smoke named as sources (notice of 10 August 2026). Check Air4Thai on the day rather than assuming.
Sources
- TMD. Climatological Data for the Period 1991-2020 (stations 48 327, 48 455, 48 461, 48 475, 48 501, 48 550, 48 561, 48 563, 48 564)
- TMD. Thailand's seasons and climate, PDF pp. 2, 4 (in Thai)
- TMD. 3-month climate prediction, July-September 2026 (issued 22 June 2026)
- TMD. Monthly Weather Summary, July 2026
- MOTS. Tourism statistics by province 2025 (xlsx)
- DNP. National park closures 2569 (2026), table dated 7 January 2026
- DNP. Mu Ko Lanta National Park (Ko Rok season)
- DNP. Mu Ko Similan National Park
- BOT. Notification 37/2569: financial institutions' holidays for 2027 (unofficial English translation)
- TAT. Important information on marine tourism during the Southwest monsoon season (24 July 2018)
- Rawai Municipality. Nai Harn Beach (in Thai)
- Karon Municipality. Karon Beach (in Thai)
- TAT. July 2026 Event and Calendar (26 June 2026)
- TAT. Ayutthaya Aquatic Phansa Festival (Khao Phansa follows the eighth-month full moon), 2022
- PCD Regional Environment Office 14. PM2.5 risk periods by region (10 August 2026, in Thai)
Found an error or outdated fact? Tell the editors, we will fix it and update the check date.