Best Time to Fly ORD to ONT
Chicago to Ontario — month-by-month delay data from the Bureau of Transportation Statistics.
Best month
March
1% on time
Worst month
April
0% on time
ORD → ONT on-time performance by month
25
26
JanFebMarAprMayJunJulAugSepOctNovDec
Worse
Better
Monthly breakdown
| Month | On-time | Cancel rate | Flights |
|---|---|---|---|
| March | 1% | 0% | 27 |
| April | 0% | 0% | 30 |
| May | 1% | 0% | 41 |
| June | 1% | 0% | 60 |
| July | 1% | 0% | 62 |
| August | 1% | 0% | 31 |
| September | 1% | 0% | 30 |
| October | 1% | 0% | 31 |
| November | 1% | 0% | 30 |
| December | 1% | 0% | 14 |
Frequently asked
What is the best month to fly from ORD to ONT?
March has the highest on-time rate at 1% for flights from Chicago to Ontario.
What is the worst month to fly ORD to ONT?
April has the lowest on-time rate at 0%, often due to seasonal weather patterns.
How often are ORD to ONT flights delayed?
On average, 1% of flights from ORD to ONT arrive on time. That means about 99% experience some form of delay.
Source: Bureau of Transportation Statistics.