Charles M. Schulz - Sonoma County in September 2025

81.0%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 September 2025, reporting carriers scheduled 484 domestic departures from Charles M. Schulz - Sonoma County (STS). 81.0% left less than 15 minutes late and 80.2% reached their destination on time; 0.6% were cancelled.

Nationally that month, 83.1% of flights departed on time and 82.8% arrived on time, so STS departures were 2.1 points below the national departure figure.

A year earlier, in September 2024, the airport had 345 departures with 83.2% leaving on time: a change of −2.2 points, with flights up 40%.

Flights arriving at STS that month were on time 84.1% of the time (484 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, late-arriving aircraft 61%, air carrier 23% and national aviation system 16%.

On time 80.2%
Arrived 15+ minutes late 19.0%
Cancelled 0.6%
Diverted 0.2%

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

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

Measure	Sep 2025	Sep 2024	STS, 12 months to Jul 2026	All reported flights, Sep 2025
Departed on time	81.0%	83.2%	80.4%	83.1%
Arrived on time	80.2%	77.7%	78.8%	82.8%
Cancelled	0.6%	0.3%	1.7%	0.5%
Average departure delay (late minutes only)	16.2 min	10.0 min	13.2 min	12.2 min
Scheduled departures a day	16	12	16	18,748
Scheduled departures	484	345	5,714	562,439

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
OO SkyWest Airlines	368	76%	79.9%	10.0 min	0.5%
AS Alaska Airlines	60	12%	73.3%	7.4 min	0.0%
MQ Envoy Air	54	11%	90.7%	-2.5 min	1.9%
AA American Airlines	2	0%	50.0%	102.0 min	0.0%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
STS–SAN	Santa Rosa to San Diego	81	70.4%	14.5 min	2.5%
STS–LAX	Santa Rosa to Los Angeles	77	79.2%	8.3 min	0.0%
STS–PDX	Santa Rosa to Portland	60	95.0%	-12.9 min	0.0%
STS–SEA	Santa Rosa to Seattle	60	73.3%	7.4 min	0.0%
STS–SNA	Santa Rosa to Santa Ana	60	78.3%	11.6 min	0.0%
STS–PHX	Santa Rosa to Phoenix	56	78.6%	35.1 min	1.8%
STS–BUR	Santa Rosa to Burbank	30	90.0%	-5.7 min	0.0%
STS–DFW	Santa Rosa to Dallas/Fort Worth	30	86.7%	6.6 min	0.0%
STS–LAS	Santa Rosa to Las Vegas	30	83.3%	3.9 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), September 2025.

Delay causes

BTS cause category	Share of delay minutes	National, Sep 2025	Minutes
Air carrier	22.8%	34.3%	1,760
Late-arriving aircraft	60.7%	37.4%	4,690
National Aviation System	15.7%	22.6%	1,214
Extreme weather	0.8%	5.6%	58
Security	0.0%	0.1%	0

7,722 delay minutes on 92 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 September 2025?

81.0% of 484 scheduled domestic departures left less than 15 minutes late, and 80.2% reached their destination on time. The national figures that month were 83.1% and 82.8%.

How does that compare with a year earlier?

In September 2024, 83.2% of 345 departures left on time and 0.3% were cancelled, against 81.0% and 0.6% in September 2025.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for September 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.