Doi InthanonWaterfalls and nature
Rivers at their most dramatic
Waterfalls and rivers run at their absolute fullest and most dramatic. Visiting mountain areas like Doi Inthanon National Park reveals deeply saturated, mist-veiled forests.
Chiang Mai · September 2026
Go when the north goes quiet
Fewer crowds. Fuller rivers. Dawn race starts.
September is low season for international visitors — and high season for water, green, and anyone who would rather move than queue. Fitness travellers get mist forests, emerald paddies, an unhurried old city, and a night sky worth staying up for.
Last-minute getaways
Chiang Mai is on this week’s deal list
Low season is when fares and stays move. Search last-minute getaway deals that include Chiang Mai — then start the day on a trail, not in a queue.
- Chiang Mai
- This week
- Partner offer
Why September
Highlights & activities
Rainy-season Chiang Mai is not a write-off. It is the month the mountains look like they mean it — and the temples, cafés, and spa rooms finally have room to breathe.
Doi Inthanon
Ban Pa Pong PiangRice terraces
Emerald paddies in the hills
Rural valleys and terraced rice paddies (such as in Ban Pa Pong Piang) are a striking, vibrant emerald — a long, quiet walk between the bunds if you start early.
Old cityFewer crowds
Temples, cafés, and spas at your pace
Because it is low season for international tourism, popular historic temples, cafés, and spas inside the city can be enjoyed at a peaceful, unhurried pace.
Mae Rim · NARIT
Princess Sirindhorn AstroPark
Night sky over Chiang Mai
Moon occultation of Venus
ดวงจันทร์บังดาวศุกร์
A special public viewing at Princess Sirindhorn AstroPark in Mae Rim on 14 September 2026, from 6:00 PM to 8:00 PM. Telescope setups near the planetarium and exhibition buildings. Free admission.
- 14 September 2026
- 6:00–8:00 PM
- Free admission
The seasonal outdoor NARIT Public Night Saturday stargazing program runs from November to May. In September the indoor planetarium and exhibitions stay open — worth the trip even if the lawn telescopes are off-season.
Regular September operations
- Planetarium & astronomy exhibitions
- Tuesday–Friday 9:00 AM–4:00 PM · Saturday–Sunday 10:00 AM–5:00 PM · Closed Mondays
- Admission
- Astronomy exhibition: free. Planetarium shows: 50 THB adults, 30 THB students.
- On-site dining
- The Planet restaurant is open for coffee, tea, and meals overlooking the grounds.
Race weekend
Upcoming September 2026 events
26–27 September 2026
Bangkok Airways Chiang Mai Half Marathon 2026
Royal Park Rajapruek, Mueang Chiang Mai District, Chiang Mai
A major annual race featuring a 5 km fun run, 10 km, 21 km half marathon, and a kids series. PUMA finisher shirts for qualifying distances.
- Kids Series · 26 Sept · 5:00 PM
- Half marathon · 27 Sept · 4:30 AM
- 10K · 5:30 AM
- 5K · 6:00 AM
Registration required (opened in February 2026 via official channels).
Saturday 26 September 2026
Fun Fam Run 2026
Innovate Chiang Mai · sponsored by Binance TH
A morning family fun run at Princess Sirindhorn AstroPark (NARIT), Mae Hia / Chiang Mai. Start between 7:00 AM and 9:00 AM.
- Free to enter
- Optional event shirt 259 THB
- 7:00–9:00 AM
September travel FAQs
Why visit Chiang Mai in September?
It is low season for international tourism, so temples, cafés, and spas are quieter. Waterfalls and rivers run at their fullest, mountain forests at Doi Inthanon are mist-veiled, and rice terraces such as Ban Pa Pong Piang are a deep emerald.
Is Princess Sirindhorn AstroPark open in September?
Yes. Indoor planetarium and astronomy exhibitions stay open (closed Mondays). Outdoor Public Night Saturday stargazing runs November to May. On 14 September 2026 the park hosts a free public viewing of the Moon occulting Venus from 6:00 to 8:00 PM.
What fitness events are in Chiang Mai in September 2026?
The Bangkok Airways Chiang Mai Half Marathon is 26–27 September 2026 at Royal Park Rajapruek (kids series, 5K, 10K, half marathon). Fun Fam Run 2026 is a free family run on Saturday 26 September, 7:00–9:00 AM, at Princess Sirindhorn AstroPark.
Stay moving
Base yourself near the trails
When the city is quiet and the hills are loud with water, pick a stay that starts the day on foot — Mae Rim paddies, riverside loops, jungle camps.