In terms of precipitation, rainfall in Siem Reap ranges from 0.0 - 10.2 inches per month. September is typically the wettest month, when rainfall can reach 10.2 in. January is typically the driest time to visit Siem Reap when rainfall is around 0.0 in.

If weather is an important factor for your trip to Siem Reap, use this chart to help with planning. For those seeking warmer temperatures, April is the ideal time of year to visit, when temperatures reach an average of 84.2 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 75.2 F).

What is the cheapest time of day to fly from STL to SAI?

When flying from St. Louis to Siem Reap, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Most accurate provider : When it comes to deals on St. Louis-Siem Reap flights, users find the pricing of Expedia to be most consistent on Cheapflights vs. Expedia Users can find the same prices on St. Louis-Siem Reap flight deals on Cheapflights vs. Expedia <90% of the time. Price accuracy is based on data collected from St. Louis-Siem Reap flight searches over the past month and is updated monthly.

Most trusted provider : When it comes to deals on St. Louis-Siem Reap flights, Cheapflights users trust Expedia the most. Expedia has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Siem Reap flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Can I find deals for flights from St. Louis to Siem Reap that include hotel bookings?

Yes. In addition to deals on St. Louis to Siem Reap flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from St. Louis to Siem Reap?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Siem Reap.

Can I find deals for business class flights from St. Louis to Siem Reap?

Yes. Cheapflights offers flight deals from St. Louis to Siem Reap by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$3,206+ Flights from St. Louis to Siem Reap, Cambodia

Q: E

Most trusted provider : When it comes to deals on St. Louis-Siem Reap flights, Cheapflights users trust Expedia the most. Expedia has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Siem Reap flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Q: Can I find deals for flights from St. Louis to Siem Reap that include hotel bookings?

Yes. In addition to deals on St. Louis to Siem Reap flights, Cheapflights offers vacation packages that include both flights and hotel.

Q: How can I find direct flights from St. Louis to Siem Reap?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Siem Reap.

Q: Can I find deals for business class flights from St. Louis to Siem Reap?

Yes. Cheapflights offers flight deals from St. Louis to Siem Reap by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

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Cheap flight deals from St. Louis to Siem Reap

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Cheapest flights from St. Louis to Siem Reap
Explore the most affordable flight options available from St. Louis to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on February 13, 2026.

Sun 3/2910:33 am

STL

SAI

3 stops34h 27m

Multiple Airlines

Sun 4/54:00 pm

SAI

STL

3 stops35h 24m

Multiple Airlines

Deal found 2/11

$3,206

Find flight deals from St. Louis to Siem Reap

Most accurate provider	Expedia 1 star
Most trusted provider	Expedia 3 stars
Round-trip from	$3,206 (Flightnetwork)

Provider with most accurate pricing for Lambert-St Louis-Siem Reap–Angkor Intl flight deals.

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St. LouisSiem Reap

STL - SAI

STLSAI

Lambert-St Louis

Sun 3/29

10:33 am-9:00 am

3 stops34h 27m

Siem Reap–Angkor Intl

Sun 4/5

4:00 pm-3:24 pm

3 stops35h 24m

$3,206

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Deals found on 2/11

Most accurate provider: When it comes to deals on St. Louis-Siem Reap flights, users find the pricing of Expedia to be most consistent on Cheapflights vs. Expedia Users can find the same prices on St. Louis-Siem Reap flight deals on Cheapflights vs. Expedia <90% of the time. Price accuracy is based on data collected from St. Louis-Siem Reap flight searches over the past month and is updated monthly.
Most trusted provider: When it comes to deals on St. Louis-Siem Reap flights, Cheapflights users trust Expedia the most. Expedia has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Siem Reap flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from St. Louis to Siem Reap

Have a flexible travel schedule? Discover the best time to fly to Siem Reap from St. Louis with our price prediction graph.

STL-SAI

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Related info for your journey

Can I find deals for flights from St. Louis to Siem Reap that include hotel bookings?
Yes. In addition to deals on St. Louis to Siem Reap flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from St. Louis to Siem Reap?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Siem Reap.
Can I find deals for business class flights from St. Louis to Siem Reap?
Yes. Cheapflights offers flight deals from St. Louis to Siem Reap by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

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$3,206+ Cheap flights from St. Louis (STL) to Siem Reap, Cambodia (SAI)

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 3/29. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from St. Louis to Siem Reap with Cheapflights

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Cheapest flights from St. Louis to Siem ReapExplore the most affordable flight options available from St. Louis to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on February 13, 2026.

Explore the most affordable flight options available from St. Louis to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on February 13, 2026.

Best flights from St. Louis to Siem ReapDiscover carefully curated flight deals from St. Louis to Siem Reap that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated February 13, 2026.

Discover carefully curated flight deals from St. Louis to Siem Reap that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated February 13, 2026.

Last-minute flights from St. Louis to Siem ReapDiscover last-minute flight deals from St. Louis to Siem Reap. Data last updated February 13, 2026 and is based on user searches.

Discover last-minute flight deals from St. Louis to Siem Reap. Data last updated February 13, 2026 and is based on user searches.

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Related info for your journey

Find useful and relevant information for your journey from St. Louis to Siem Reap. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

Can I find deals for flights from St. Louis to Siem Reap that include hotel bookings?

How can I find direct flights from St. Louis to Siem Reap?

Can I find deals for business class flights from St. Louis to Siem Reap?

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St. Louis and Siem Reap flights

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Cheapest flights from St. Louis to Siem Reap
Explore the most affordable flight options available from St. Louis to Siem Reap. Find the lowest fares from popular airlines and budget airlines, with prices last updated on February 13, 2026.

Best flights from St. Louis to Siem Reap
Discover carefully curated flight deals from St. Louis to Siem Reap that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated February 13, 2026.

Last-minute flights from St. Louis to Siem Reap
Discover last-minute flight deals from St. Louis to Siem Reap. Data last updated February 13, 2026 and is based on user searches.