Airport · DEC · Decatur, Illinois
Decatur, IL
Decatur, IL posts above-median on-time performance among the 382 tracked U.S. airports, as a smaller regional airport. According to the U.S. DOT Bureau of Transportation Statistics, drawn from 9,084 flights (2020–2025); its biggest delay driver is carrier.
Data updated 2026-06-13
- 84.5%
- On-time
- Top 38%
- on-time, US airports
- 128 min
- Delay when late
- 1.70%
- Cancelled
Key Performance Metrics
Total Flights
9,084
Best Month
Oct 94.9%
Worst Month
Dec 90.6%
Delayed
1,405
Cancelled
154
DEC on-time rate vs. the national average
Ahead of the U.S. average across all 382 tracked airports.
Where DEC sits among all 382 tracked airports
DEC's 84.5% on-time rate falls in the 80-85% band, the 192-airport band it shares.
National on-time-rate distribution
- 60-65% 1
1 airport between 60% and 65% on-time
1 airports
- 65-70% 4
4 airports between 65% and 70% on-time
4 airports
- 70-75% 9
9 airports between 70% and 75% on-time
9 airports
- 75-80% 48
48 airports between 75% and 80% on-time
48 airports
- 80-85%
192 airports between 80% and 85% on-time
192 airports
- 85-90%
116 airports between 85% and 90% on-time
116 airports
- 90-95% 12
12 airports between 90% and 95% on-time
12 airports
What this shows DEC is marked in the 80-85% band.
Delay Cause Breakdown
Top delay cause: Carrier. Total delay minutes: 106,781.
DEC - seasonal on-time pattern
Best: October (94.9%) · worst: December (90.6%)
Seasonal Performance Patterns
Monthly averages across all years of data. Best month: October (94.9% on-time). Most delays: December (90.6% on-time).
| Month | Avg Flights | Avg Delayed | Avg Cancelled | On-Time % |
|---|---|---|---|---|
| December | 127 | 25 | 3 | 90.6% |
| November | 126 | 17 | 1 | 93.8% |
| October | 128 | 13 | 1 | 94.9% |
| September | 130 | 20 | 0 | 92.9% |
| August | 134 | 25 | 3 | 92.2% |
| July | 133 | 28 | 2 | 90.6% |
| June | 124 | 21 | 1 | 92.3% |
| May | 140 | 18 | 2 | 94.1% |
| April | 141 | 15 | 1 | 94.8% |
| March | 124 | 14 | 1 | 94.6% |
| February | 120 | 22 | 3 | 91.6% |
| January | 130 | 23 | 9 | 92.3% |
Year-Over-Year Performance
Annual flight volume and on-time trends at DEC.
DEC - on-time rate by year
2020–2025, year-over-year trend.
| Year | Flights | Delayed | Cancelled | On-Time % |
|---|---|---|---|---|
| 2025 | 1,254 | 108 | 17 | 91.4% |
| 2024 | 1,560 | 150 | 18 | 90.4% |
| 2023 | 1,972 | 170 | 19 | 91.4% |
| 2022 | 2,091 | 129 | 52 | 93.8% |
| 2021 | 1,252 | 54 | 36 | 95.7% |
| 2020 | 955 | 31 | 12 | 96.8% |
Cancellation & Diversion Analysis
Flight disruption statistics for Decatur, IL.
Cancellation Rate
1.70%
154 of 9,084 flights
Diversion Rate
0.09%
8 of 9,084 flights
Delay Rate
15.5%
1,405 of 9,084 flights
Monthly Performance
Recent 24 months of flight data.
| Period | Flights | Dep Delayed | Arr Delayed | Cancelled | Diverted |
|---|---|---|---|---|---|
| Dec 2025 | 110 | 14 | 20 | 4 | 1 |
| Nov 2025 | 100 | 11 | 14 | 3 | 0 |
| Oct 2025 | 108 | 10 | 7 | 0 | 0 |
| Sep 2025 | 102 | 9 | 7 | 0 | 0 |
| Aug 2025 | 106 | 7 | 13 | 2 | 0 |
| Jul 2025 | 106 | 9 | 14 | 4 | 0 |
| Jun 2025 | 104 | 8 | 11 | 0 | 0 |
| May 2025 | 106 | 3 | 2 | 1 | 0 |
| Apr 2025 | 102 | 7 | 6 | 0 | 0 |
| Mar 2025 | 106 | 10 | 13 | 0 | 0 |
| Feb 2025 | 96 | 13 | 16 | 1 | 0 |
| Jan 2025 | 108 | 7 | 15 | 2 | 0 |
| Dec 2024 | 106 | 13 | 14 | 0 | 0 |
| Nov 2024 | 104 | 9 | 14 | 0 | 0 |
| Oct 2024 | 106 | 2 | 5 | 0 | 0 |
| Sep 2024 | 104 | 9 | 14 | 0 | 0 |
| Aug 2024 | 106 | 15 | 26 | 0 | 1 |
| Jul 2024 | 106 | 13 | 16 | 0 | 0 |
| Jun 2024 | 104 | 13 | 15 | 0 | 1 |
| May 2024 | 170 | 25 | 26 | 5 | 0 |
| Apr 2024 | 162 | 14 | 17 | 0 | 0 |
| Mar 2024 | 168 | 12 | 12 | 0 | 0 |
| Feb 2024 | 158 | 10 | 7 | 0 | 0 |
| Jan 2024 | 166 | 15 | 18 | 13 | 0 |
Top Routes from DEC
Busiest routes to and from Decatur, IL.
| Route | Flights | On-Time | Distance |
|---|---|---|---|
| ORD (Chicago) → DEC (Decatur) | 3,614 | 82.6% | 156 mi |
| DEC (Decatur) → ORD (Chicago) | 3,543 | 83.4% | 156 mi |
Airports With a Similar On-Time Rate
Other U.S. airports nationwide whose on-time rate is closest to Decatur, IL's 84.5%.
Other Airports in Illinois
Compare performance with other Illinois airports.
Chicago, IL
Chicago · 3,114,086 flights
Chicago, IL
Chicago · 880,912 flights
Moline, IL
Moline · 45,407 flights
Peoria, IL
Peoria · 44,104 flights
Bloomington/Normal, IL
Bloomington/Normal · 25,097 flights
Champaign/Urbana, IL
Champaign/Urbana · 17,865 flights
Belleville, IL
Belleville · 14,072 flights
Rockford, IL
Rockford · 9,512 flights
Keep exploring
More flight data around Decatur, IL.
Illinois flight data
Statewide on-time and delay aggregates, plus every reporting airport in Illinois.
View IL data →Airport rankings
See where DEC sits among U.S. airports on on-time rate and average delay.
Best on-time airports →Compare airports
Put DEC head-to-head with another airport on delays and reliability.
Open comparison tool →What the Data Says About DEC
Decatur, IL in Decatur, Illinois handled 9,084 flights in the Bureau of Transportation Statistics dataset between 2020 and 2025, posting a 84.5% on-time departure rate. Of those flights, 1,405 experienced delays, 154 were cancelled, and 8 were diverted. The cancellation rate works out to 1.70%, the diversion rate to 0.09%, and the average delay when departures run late is 127.5 minutes. These figures are the baseline for comparing DEC against other airports in the same state and nationally.
Breaking down what drives delays at DEC, Carrier leads the pack. Carrier accounts for 48.9% of total delay minutes, followed by Late Aircraft at 39.8% and NAS (National Aviation System) at 6.1%. Weather contributes 5.1% of delay minutes at this airport, while security holds the smallest share at 0.0%. Travelers often overestimate the weather share; the BTS categorization shows late-arriving aircraft and carrier operations as the larger contributors.
Seasonally, October runs the cleanest at DEC with a 94.9% on-time rate, while December is the roughest at 90.6% - a 4-point swing between best and worst month. Volume peaks in April, when average flights hit 141. The busiest route connecting DEC is to ORD (Chicago), with 3,614 flights at a 82.6% on-time rate. Combine these numbers - 84.5% on-time, 127.5-minute average delay, 1.70% cancellation rate, and you have a concrete picture of departure reliability at Decatur, IL.
Frequently Asked Questions
What is the on-time performance rate at Decatur, IL (DEC)? ▼
What is the most common cause of delays at DEC? ▼
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Flight Guides
Data-driven guides to help you understand airport and flight performance.
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Read our methodology - how this data is sourced, computed, and verified.
Using DEC's data
An airport-level on-time rate is a starting point, not a guarantee for your specific flight.
- Check the busiest route from DEC before you book a connection. See top routes
- Travel in October rather than December if your dates are flexible. Seasonal patterns
- Scores vary by airline and route within the same airport; check the specific carrier you're flying. Browse airlines
On-time rate reflects the BTS historical average across all reporting carriers at this airport, not any single flight or airline.
Related
Source: U.S. Bureau of Transportation Statistics (BTS) Airline on-time performance and operational reliability · 2025
Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. Airport figures are computed directly from BTS On-Time Performance data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.