MDW to SFO flight delays
Chicago, IL (MDW) San Francisco, CA (SFO) · 1,855 miles
455 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
49.33%
Arrived on time
Within 15 minutes of schedule
1.32%
Cancelled
Share of scheduled flights
58 min
When late, late by
Average across delayed arrivals
30 min
Delay per flight
Averaged over every flight flown
What the record says about this route
The season swings this route hard. In August it ran 61.2 points more punctual than in May — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
Flights from Chicago to San Francisco arrive late more often than they arrive on time. At this rate lateness is the normal outcome, not the exception, and the schedule is better read as an aspiration than a plan.
The two directions do not behave alike. SFO to MDW arrives on time 25.7 points more often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
The route has been getting worse. The later months run 35.7 points less punctual than the earlier ones. A drift of that size is rarely weather; it is more often an airline adding frequencies faster than the airports can absorb them.
Which airline should you fly on this route?
Over January 2025 – August 2026, Southwest Airlines arrived on time most often on MDW to SFO. Flights ran closest to schedule in February and worst in May.
Every airline on MDW to SFO
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 455 | 49.33% | 1.32% | 58 min | F |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
SFO to MDW San Francisco back to Chicago 75.06% on time DOther routes from Chicago
Common questions
Are flights from Chicago to San Francisco usually delayed?
49.33% of flights on the MDW to SFO route arrived within 15 minutes of schedule, so roughly 5 in every ten arrived late. That is worse than the average route in this record.
Which airlines fly from Chicago to San Francisco?
Only Southwest Airlines appears in the published record on this route, with 455 flights and 49.33% arriving on time.
How often are MDW to SFO flights cancelled?
1.32% of scheduled flights did not operate — about 13 in every thousand. That is in the normal range.
What is the best month to fly Chicago to San Francisco?
August, when 80.6% of flights arrived on time. The worst was May at 19.4%.
When MDW to SFO flights are late, how late are they?
About 58 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on MDW to SFO during January 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →