Airport month record

LASDEC

Harry Reid International in December 2025

Departures: 14,547
Month: December 2025
National, same month: 73.2%
Carriers: 11

Historical statistics for December 2025, not live status or a forecast for this year’s December. For today’s conditions at LAS, see live FAA status.

LAS in December lands a B+, 7 points better than the national rate of 73.2%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 14,547 flights, of which Allegiant Air flew 717 at 86.6% on time.

Allegiant Air is the most reliable of the nine carriers covered here at 86.6% on time across 717 flights.

On time

79.9%

Arrivals under 15 minutes late, of 14,428 completed departures

Avg delay

59 min

Across delayed arrivals only, not all flights

Cancelled

0.60%

Nationally in December: 1.55%

Whole year

77.9%

LAS across all twelve months

These figures cover 14,547 departures from Harry Reid International in December 2025. On time means an arrival less than 15 minutes after the scheduled gate time, the DOT's threshold, and the national comparison uses every US departure in the same month rather than the whole year.

Against the year

December next to LAS's other months

Against LAS's own year, December ran 2 points better than the twelve-month rate of 77.9%, which makes it number three of twelve months, best first. Either side of it, November ran 79.5% on time and January 83.1%, so this month sits in line with its neighbours.

LAS month by month
Month	Flights	On time	Avg delay	Cancelled	Grade
July 2025	15,733	72.9%	67 min	1.13%	C
August 2025	14,920	79.6%	59 min	0.50%	B+
September 2025	14,399	78.8%	66 min	0.53%	B+
October 2025	15,597	77.1%	62 min	0.31%	B+
November 2025	14,443	79.5%	59 min	1.73%	B
December 2025 (this page)	14,547	79.9%	59 min	0.60%	B+
January 2026	13,695	83.1%	65 min	1.86%	B
February 2026	12,886	83.1%	58 min	0.88%	B+
March 2026	15,169	78.3%	60 min	1.15%	B
April 2026	14,672	78.8%	54 min	0.40%	B+
May 2026	14,585	74.1%	60 min	0.67%	C+
June 2026	13,704	70.7%	61 min	0.77%	C+

Departure window

The best time of day to leave LAS in December

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am2,310 flights91.5%
8am–11am3,034 flights84.2%
11am–2pm2,634 flights78.5%
2pm–5pm2,378 flights75.9%
5pm–8pm2,147 flights72.6%
8pm–5am2,044 flights74.6%

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 91.5% of the time, against 72.6% for the evening window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 3,034 flights scheduled in it.

Across the week, Thursday is the strongest day at 84.9% on time and Sunday the weakest at 71.7%. 13 points is a smaller lever than departure hour, but it is free.

Carrier by carrier

Which airlines ran best at LAS in December

The choice of carrier is not cosmetic here. Allegiant Air arrives on time 86.6% of the time; Alaska Airlines manages 73.7%. Sample sizes sit next to every figure, because a two-point gap across 495 flights means less than a ten-point one.

Carriers at LAS in December 2025
Airline	Flights	On time	Avg delay	Cancelled	Grade
Southwest Airlines	7,299	77.1%	46 min	0.40%	B+
Delta Air Lines	1,306	86.1%	83 min	1.30%	A
United Airlines	1,285	84.2%	58 min	0.08%	B+
American Airlines	1,167	84.1%	97 min	0.34%	B+
Frontier Airlines	957	77.0%	76 min	1.88%	B
Allegiant Air	717	86.6%	75 min	0.14%	A+
Spirit Airlines	506	86.1%	99 min	1.58%	A
Alaska Airlines	495	73.7%	51 min	0.81%	C+
SkyWest Airlines	369	80.1%	72 min	0.27%	B+
JetBlue Airwaysthin sample	304	84.3%	71 min	1.32%	B
Hawaiian Airlinesthin sample	142	70.0%	113 min	0.70%	C+

The spread between Allegiant and Alaska is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.

Route by route

Busiest routes out of LAS in December

Routes from LAS in December 2025
Route	Flights	On time	Avg delay	Cancelled	Grade
LAS to LAX · Los Angeles	683	81.1%	54 min	0.29%	B+
LAS to DEN · Denver	556	80.2%	59 min	0.54%	B+
LAS to SFO · San Francisco	510	67.1%	65 min	0.39%	C+
LAS to PHX · Phoenix	497	81.4%	60 min	0.40%	B+
LAS to SAN · San Diego	477	62.7%	50 min	1.05%	D
LAS to SEA · Seattle	468	77.4%	60 min	0.64%	B+
LAS to DFW · Dallas-Fort Worth	446	86.6%	87 min	1.57%	A
LAS to ATL · Atlanta	429	88.9%	95 min	1.17%	A
LAS to BUR · Burbank	366	77.0%	68 min	1.91%	B
LAS to SNA · Santa Anathin sample	363	82.4%	47 min	0.28%	B+
LAS to ORD · Chicagothin sample	359	76.1%	84 min	0.84%	B+
LAS to SMF · Sacramentothin sample	354	82.2%	44 min	0.00%	B+
LAS to SJC · San Josethin sample	318	75.8%	51 min	0.00%	B+
LAS to SLC · Salt Lake Citythin sample	314	86.8%	50 min	1.27%	A
LAS to IAH · Houstonthin sample	309	91.6%	68 min	0.00%	A+
LAS to RNO · Renothin sample	306	79.1%	64 min	1.31%	B
LAS to JFK · New Yorkthin sample	285	83.2%	86 min	3.16%	B−
LAS to DAL · Dallasthin sample	257	81.7%	42 min	0.00%	B+
LAS to AUS · Austinthin sample	253	83.8%	58 min	0.00%	B+
LAS to OAK · Oaklandthin sample	247	76.1%	40 min	0.00%	B+
LAS to PDX · Portlandthin sample	239	72.4%	45 min	0.00%	C+
LAS to DTW · Detroitthin sample	224	76.2%	69 min	0.45%	B+
LAS to ONT · Ontariothin sample	207	76.1%	49 min	0.97%	B+
LAS to SAT · San Antoniothin sample	205	78.0%	67 min	0.00%	B+
LAS to EWR · Newarkthin sample	200	82.8%	77 min	0.50%	B+

Delay causes

What held LAS up in December

One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 172,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
48%
Carrier
34%
National Airspace System
15%
Extreme weather
2%
Security
0%

48% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 172,000 reported delay minutes here, that single category outweighs weather by 21 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 171,921 reported delay minutes.

Cancellations are rare at 0.60%, below the national 1.55% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

5.7% of arrivals land an hour or more late, close to the national 10.0%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

What to do with this

Flying from LAS in December

For a December trip through LAS: this is one of the better months to be flying from here, 79.9% on time with 0.60% cancelled. That is a base rate for the month as a whole; a single storm can still spoil a particular day.

Harry Reid International (LAS), the whole year
LAS in July72.9%
LAS in August79.6%
LAS in September78.8%
LAS in October77.1%
LAS in November79.5%
LAS in January83.1%
LAS in February83.1%
LAS in March78.3%
LAS in April78.8%
LAS in May74.1%
LAS in June70.7%

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures