Rainy season, safety and preparation
Jun – Oct
Path from the landing — Slippery rocks, rope sections
Half a day
Weak to none in the valley
6 days ahead
When to go
this week
Tap a day card to see that day’s weather, rain, haze and hourly forecast
Best time to go Best window 06:00–12:00 Little rain
Rain at times — slippery roads, allow extra travel time
Holiday — traffic on the way up and parking fills fast; leave early
Hour by hour
Green band = hours used for the score
Best time to go Best window 06:00–15:00 Little rain · light drizzle possible at times
Holiday — traffic on the way up and parking fills fast; leave early
Hour by hour
Green band = hours used for the score
Best time to go Fine all day little rain through the day · light drizzle possible at times
Thick morning fog with visibility under 1 km — use headlights and drive slowly
Holiday — traffic on the way up and parking fills fast; leave early
Hour by hour
Green band = hours used for the score
Best time to go Best window 06:00–12:00 Little rain
Rain at times — slippery roads, allow extra travel time
Thick morning fog with visibility under 1 km — use headlights and drive slowly
Hour by hour
Green band = hours used for the score
Best time to go Best window 06:00–14:00 Little rain · light drizzle possible at times
Thick morning fog with visibility under 1 km — use headlights and drive slowly
Hour by hour
Green band = hours used for the score
Best time to go Fine all day little rain through the day · light drizzle possible at times
No warnings today — normal road and weather conditions
Hour by hour
Green band = hours used for the score
Starry sky
How likely
Scored from cloud cover at every level and tonight’s moonlight — the darker the sky, the clearer the Milky Way · tap another night below for the next 7 nights
Khao Chong Lom
Khao Chong Lom, behind Khun Dan Prakan Chon Dam, Ban Tha Dan, Hin Tang, Mueang Nakhon Nayok.
- First boats, soft light
- Harsh sun, no shade
- Last boats
Arrive 15:00
- Chong Lom fallsWater over bouldersMorning
- Valley grasslandGreen grass and rocksMorning
- Lone dead treePopular frameMorning
- From the boatDam crest and hillsEn route
Gallery
Photos from Wikimedia Commons and contributors · full credits inClassic page
Good to know here
Slippery rocks, rope sections
Flash floods after heavy rain
- Buy the boat at the pier on the dam crest; no advance booking needed
- Wear strap-on or water shoes; there are rope sections and a bamboo bridge
- Bring a hat, sunscreen and water
- Weekdays have fewer boats — go early
Adults 0 THB · Time needed Half a day
Weekends, Jun–Oct
| Boat charter, Thai visitors 1–7 | 1,500 ฿/boat |
| Each extra person optional | 200 ฿/person |
Cash · Prices may change by season — check with the venue
- Kids OK with life jackets and close supervision
- Seniors Only if steady on rocks
- Wheelchair Not suitable — boat and rocky path
- Pets Not recommended — boat trip
- Krua HydroNear Khun Dan Dam, 037-615-469
- Krua Pla KhueanAbout 6 km, 087-343-6317
- Krua SarikaAbout 8 km, 062-501-2606
- Wear a life jacket on the boat
- Take rubbish back on the boat
- Do not swim in the reservoir
- Do not trample the grassland off the path
- The reservoir level shapes the trip: low water means longer walks; high water covers some grassland
- Slippery path with rope-assisted steep bits
- Strong sun and no shade
- Flash-flood risk in the streams after heavy rain
Best months
Tap a month on the wheel to see weather, rain, haze and crowds from 10 years of records
Best time · Jun–Sep when the reservoir drops and grassland shows · Jul–Oct for green and flowing streams · Nov high water, shorter walk · take a morning boat
Watch out · Midday — strong sun, no shade · after heavy rain (flash floods in the streams) · crowded holidays
21°Jan
22°Feb
23°Mar
24°Apr
25°May
24°Jun
24°Jul
24°Aug
24°Sep
23°Oct
22°Nov
21°Dec
Oct by the records 23–30°C · avg rain 279 mm (25 rainy days) · clear 2 days · avg PM2.5 11
The story of this place
Khao Chong Lom is a valley of streams, grassland and boulders behind Khun Dan Prakan Chon Dam at Ban Tha Dan, Hin Tang, Mueang Nakhon Nayok. "Chong Lom" means a wind gap between hills. It can be reached only by boat across the reservoir, 15–20 minutes, followed by a walk of about 400 m. The forest here is continuous with Khao Yai, declared Thailand's first national park on 18 September 1962.
Read more 4 more paragraphs
The valley's story is tied to the dam. On 9 October 1993 King Rama IX asked for a study of a reservoir on Khlong Tha Dan; construction began on 2 November 1999, and when the reservoir began filling in October 2005 the valley behind it, including Khao Chong Lom, was partly flooded, leaving a landscape that changes with the water level. No evidence of drowned villages has been found: the dam site was mostly about 500 rai of irrigation-department land, with little taken from villagers.
At first, boats from the dam crest took visitors to the falls in the reservoir. In 2019 the press described boat trips stopping at Chong Lom and Khlong Khram falls, at 1,500 THB per boat for Thai visitors. From August 2020 Khao Chong Lom became a new social-media hotspot, going viral again in 2022, and visitors nicknamed it the "Switzerland of Nakhon Nayok" for its green valley grass, although this is not an official name.
On 9 August 2023 the government's PR site announced the Khao Chong Lom tourist season for June–September, when the reservoir falls and exposes the grassland. The boat route stops at Pha Ngam Ngon, Khlong Khram and Chong Lom falls; the highlight is Chong Lom, where water slides through rock clefts into clear shallow pools you can wade in.
Today it remains a day trip that depends on boats of the Khun Dan Prakan Chon Dam long-tail boat club (089-493-1200), seating up to about 20 and running from early morning to late afternoon. The water level shapes the experience: low water reveals wide grassland but means a longer walk, while high water around November lets boats get closer to the falls. Watch for flash floods in the streams after heavy rain.
- 18 Sep 1962Khao Yai National Park declared; forest continuous with Khao Chong Lom
- 9 Oct 1993King Rama IX initiates the Khlong Tha Dan reservoir project
- 2 Nov 1999Dam construction begins
- Oct 2005Reservoir fills; the valley behind is partly flooded
- Jan 2019Boat trips stop at Chong Lom and Khlong Khram falls
- Aug 2020Khao Chong Lom goes viral on social media
- 2022Khao Chong Lom goes viral again
See 1 events
- 9 Aug 2023Government announces the Khao Chong Lom season
Check-ins & visitor photos
Arrived? Check in, collect a stamp and tell others what it is like right now
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Location must be on and within 0.9 km · One check-in per place per day · come back on other days to check in again
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How to get there
Paved road to the dam, then boat only
Drive to Khun Dan Prakan Chon Dam and charter a boat · About 1,500 THB per boat
Package with transport and boat · About 2,900 THB per person
Drive to Khun Dan Prakan Chon Dam (Hwy 3049, then NY 4016), then take a boat
Khun Dan Prakan Chon Dam car park
Nakhon Nayok town
Weak to none in the valley
Boats run from early morning to late afternoon (sources say 06:00–16:30 or 08:00–17:00)
around 20 km fromNakhon Nayok town
Khao Chong Lom
0 THB
Stays near Khao Chong Lom
Approx. nightly price for 2 adults (next week) · final price depends on your dates
FAQ
Before you goKhao Chong Lom
Answers travellers want before they go — a one-minute read
How do I get to Khao Chong Lom?
Only by boat from Khun Dan Prakan Chon Dam, 15–20 min, then about 400 m on foot
How much is the boat?
About 1,500 THB per boat for 1–7 Thai visitors, +200 THB per extra person; in 2019 foreigners paid 2,000 THB for 5
When should I go?
Jun–Oct for green grass and low reservoir; November for high water and a shorter walk
Do I need to book?
No — buy at the boat point on the dam crest; boats run about 08:00–17:00
Can I swim?
You can wade in the shallow pools at Chong Lom falls; do not swim in the reservoir
Why "Switzerland of Nakhon Nayok"?
An informal visitors' nickname for its green valley, not an official name
Ready to go to Khao Chong Lom?
Best day this week: Wednesday 28 Oct · Check in when you arrive to collect a stamp