Skip to content
WanderNerd
Check a flight

Flight Reliability

DL 4231 · Delta Air Lines

CIU → Detroit (CIU–DTW)

66
Usually Fine
WanderNerd Reliability Score
82%
Arrive within 15 minutes
8 min
Average arrival delay
5.8%
Cancelled
13 min early
Median arrival delay

Based on 363 historical flights. Data through May 2026.

What the data says

The 12–3 PM departure wins.

DL 4231 departing between 12–3 PM arrived on time 87% of the time, versus 80% between 3–6 PM.

Friday is doing you no favors.

DL 4231 arrived on time 96% of the time on Wednesdays and just 73% on Fridays. That gap is worth planning around.

Keep a backup plan handy.

DL 4231 was cancelled 5.8% of the time. Typical for U.S. flights is around 1–2%.

Trending in the right direction.

DL 4231 arrived on time 83% of the time over the last three months in the data, compared with 72% in the three months before that.

The breakdown

On-time by weekday
  • Mon83%(47 flights)
  • Tue84%(51 flights)
  • Wed96%(48 flights)
  • Thu83%(47 flights)
  • Fri73%(48 flights)
  • Sat78%(50 flights)
  • Sun80%(50 flights)
On-time by departure window
  • 6–9 AM—(8 flights)
  • 12–3 PM87%(122 flights)
  • 3–6 PM80%(211 flights)
On-time trend by month
90%
May

Jun 87% → May 90% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202587%30
July 202573%30
August 202594%31
September 202593%30
October 202587%31
November 202586%28
December 202582%28
January 202670%27
February 202663%24
March 202677%26
April 202681%26
May 202690%30
Departures on time
83%
Diverted
0.3%
Flights flown
341
Months covered
12

Keep nerding

Based on 363 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.