Charles M. Schulz - Sonoma County in December 2025

59.1%departed on time

BTS: A flight is counted as on time if it arrived less than 15 minutes after its scheduled time. Only carriers with at least 0.5 percent of domestic scheduled passenger revenue report.

In December 2025, reporting carriers scheduled 406 domestic departures from Charles M. Schulz - Sonoma County (STS). 59.1% left less than 15 minutes late and 59.6% reached their destination on time; 8.9% were cancelled.

Nationally that month, 72.0% of flights departed on time and 71.9% arrived on time, so STS departures were 12.9 points below the national departure figure.

A year earlier, in December 2024, the airport had 387 departures with 74.7% leaving on time: a change of −15.6 points, with flights up 5%.

Flights arriving at STS that month were on time 60.2% of the time (407 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, late-arriving aircraft 44%, extreme weather 29% and air carrier 14%.

On time 59.6%
Arrived 15+ minutes late 30.8%
Cancelled 8.9%
Diverted 0.7%

Every scheduled departure from STS in December 2025, judged by arrival at the destination.

December 2025 against a year earlier, the airport's year and the nation

Measure	Dec 2025	Dec 2024	STS, 12 months to Jul 2026	All reported flights, Dec 2025
Departed on time	59.1%	74.7%	80.4%	72.0%
Arrived on time	59.6%	70.0%	78.8%	71.9%
Cancelled	8.9%	1.0%	1.7%	1.5%
Average departure delay (late minutes only)	30.0 min	18.2 min	13.2 min	21.2 min
Scheduled departures a day	14	13	16	19,410
Scheduled departures	406	387	5,714	582,304

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
OO SkyWest Airlines	327	81%	57.8%	27.6 min	10.4%
MQ Envoy Air	50	12%	76.0%	5.4 min	0.0%
AS Alaska Airlines	29	7%	51.7%	13.0 min	6.9%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
STS–SNA	Santa Rosa to Santa Ana	93	59.1%	41.0 min	4.3%
STS–BUR	Santa Rosa to Burbank	62	59.7%	8.3 min	19.4%
STS–SAN	Santa Rosa to San Diego	52	55.8%	17.9 min	9.6%
STS–PHX	Santa Rosa to Phoenix	48	75.0%	5.7 min	0.0%
STS–PDX	Santa Rosa to Portland	44	70.5%	15.3 min	2.3%
STS–LAX	Santa Rosa to Los Angeles	38	57.9%	28.9 min	23.7%
STS–SEA	Santa Rosa to Seattle	30	50.0%	15.7 min	6.7%
STS–PSP	Santa Rosa to Palm Springs	21	42.9%	41.7 min	4.8%
STS–LAS	Santa Rosa to Las Vegas	16	37.5%	50.7 min	12.5%
STS–DFW	Santa Rosa to Dallas/Fort Worth	2	100.0%	-0.5 min	0.0%

By scheduled departure hour

On-time share:under 62%6270768288% and over

Share of departures that left less than 15 minutes late, by scheduled hour (local time), December 2025.

Delay causes

BTS cause category	Share of delay minutes	National, Dec 2025	Minutes
Air carrier	13.9%	33.3%	1,460
Late-arriving aircraft	44.2%	41.1%	4,639
National Aviation System	13.3%	19.1%	1,400
Extreme weather	28.6%	6.4%	3,004
Security	0.0%	0.2%	0

10,503 delay minutes on 125 flights that arrived 15 or more minutes late and carried a cause report. Carriers assign the categories; see what each category means.

Questions and answers

How many flights left STS on time in December 2025?

59.1% of 406 scheduled domestic departures left less than 15 minutes late, and 59.6% reached their destination on time. The national figures that month were 72.0% and 71.9%.

How does that compare with a year earlier?

In December 2024, 74.7% of 387 departures left on time and 1.0% were cancelled, against 59.1% and 8.9% in December 2025.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for December 2025; public domain. Domestic scheduled flights by reporting carriers, totals and averages only. The site's data runs through July 2026. Full record for STS · methodology · corrections.