Cheap flights from Ontario, CA to St. Louis, MO
Flights starting at $44. Choose between Frontier Airlines, United Airlines, or Alaska Airlines to find the best price.
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Tips to know when travelling to St. Louis
Cheapest one-way trip | $209 |
---|---|
Cheapest round-trip | $466 |
Most popular airline | Frontier Airlines |
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The most popular airlines for this route are Frontier Airlines, United Airlines, Alaska Airlines, JetBlue Airways, and Spirit Airlines. Ontario and St. Louis have 108 direct flights per week.
Check-in for a flight from Ontario to St. Louis
Name | Carrier code | IATA Code | Passport needed during booking | Online check-in available |
---|---|---|---|---|
Frontier Airlines | FFT | F9 | No | Opens 24 days before flight Closes 1 hours before flight |
United Airlines | UAL | UA | Yes | No |
Alaska Airlines | ASA | AS | No | Opens 24 days before flight Closes 1 hours before flight |
JetBlue Airways | JBU | B6 | No | Opens 24 days before flight Closes 2 hours before flight |
Spirit Airlines | NKS | NK | No | Opens 24 days before flight Closes 1 hours before flight |
Weather in St. Louis
Average Weather
Month | Average monthly max temperature | Average monthly min temperature |
January | 3°C | -3°C |
February | 6°C | -2°C |
March | 13°C | 3°C |
April | 18°C | 8°C |
May | 24°C | 14°C |
June | 29°C | 19°C |
July | 31°C | 21°C |
August | 30°C | 20°C |
September | 27°C | 16°C |
October | 20°C | 10°C |
November | 12°C | 3°C |
December | 7°C | 0°C |
14 day forecast
Frequently asked questions
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