August is the cheapest month to fly this route, with average fares around $255 round trip.
Average round-trip fares by departure month, based on current availability.
| Month | Avg Price | Lowest | Relative Cost | |
|---|---|---|---|---|
| May 2026 | $300 | $250 | Peak | |
| June 2026 | $290 | $250 | ||
| July 2026 | $259 | $230 | ||
| August 2026 | $255 | $244 | Best |
Departing on Saturday offers the lowest average fares at $274. Monday departures are the most expensive at $281, a difference of $7.
The best time to fly is August. Set up an alert and we'll notify you when prices drop.
Get Started Free →The cheapest month to fly from Portland to Chicago is August, with average round-trip fares around $255. The lowest fare found in August is $244.
Saturday departures are the cheapest, averaging $274 round trip. The most expensive day is Monday at $281.
Based on current pricing trends, booking for August travel offers the best value. Avoid May if possible, as fares average $300 compared to $255 in the cheapest month. June is a solid middle-ground option at $290.
Flying in August instead of May can save you approximately $45 per round trip. The cheapest month averages $255 while the most expensive averages $300.
Airlines, flight times, price calendar, and more for Portland to Chicago
View PDX → ORD Details