Charles M. Schulz - Sonoma County in August 2025

79.5%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 August 2025, reporting carriers scheduled 435 domestic departures from Charles M. Schulz - Sonoma County (STS). 79.5% left less than 15 minutes late and 77.7% reached their destination on time; 0.5% were cancelled.

Nationally that month, 76.8% of flights departed on time and 76.3% arrived on time, so STS departures were 2.7 points above the national departure figure.

A year earlier, in August 2024, the airport had 338 departures with 83.4% leaving on time: a change of −3.9 points, with flights up 29%.

Flights arriving at STS that month were on time 83.0% of the time (435 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, late-arriving aircraft 44%, air carrier 34% and national aviation system 16%.

On time 77.7%
Arrived 15+ minutes late 21.6%
Cancelled 0.5%
Diverted 0.2%

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

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

Measure	Aug 2025	Aug 2024	STS, 12 months to Jul 2026	All reported flights, Aug 2025
Departed on time	79.5%	83.4%	80.4%	76.8%
Arrived on time	77.7%	77.5%	78.8%	76.3%
Cancelled	0.5%	0.0%	1.7%	1.1%
Average departure delay (late minutes only)	12.6 min	8.6 min	13.2 min	17.6 min
Scheduled departures a day	15	11	16	20,079
Scheduled departures	435	338	5,714	602,378

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
OO SkyWest Airlines	331	76%	80.4%	5.6 min	0.3%
AS Alaska Airlines	42	10%	57.1%	19.7 min	2.4%
AA American Airlines	36	8%	66.7%	22.4 min	0.0%
MQ Envoy Air	26	6%	92.3%	-5.0 min	0.0%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
STS–SAN	Santa Rosa to San Diego	71	77.5%	7.6 min	0.0%
STS–LAX	Santa Rosa to Los Angeles	69	84.1%	10.7 min	0.0%
STS–PHX	Santa Rosa to Phoenix	62	91.9%	-3.5 min	0.0%
STS–SEA	Santa Rosa to Seattle	62	58.1%	19.6 min	1.6%
STS–SNA	Santa Rosa to Santa Ana	62	75.8%	5.8 min	1.6%
STS–PDX	Santa Rosa to Portland	43	86.0%	-3.4 min	0.0%
STS–DFW	Santa Rosa to Dallas/Fort Worth	31	61.3%	27.5 min	0.0%
STS–BUR	Santa Rosa to Burbank	23	87.0%	-3.3 min	0.0%
STS–LAS	Santa Rosa to Las Vegas	12	75.0%	8.0 min	0.0%

By scheduled departure hour

100

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

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

Delay causes

BTS cause category	Share of delay minutes	National, Aug 2025	Minutes
Air carrier	34.1%	33.1%	1,841
Late-arriving aircraft	44.1%	40.5%	2,379
National Aviation System	16.3%	19.2%	877
Extreme weather	5.5%	7.0%	296
Security	0.0%	0.1%	0

5,393 delay minutes on 94 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 August 2025?

79.5% of 435 scheduled domestic departures left less than 15 minutes late, and 77.7% reached their destination on time. The national figures that month were 76.8% and 76.3%.

How does that compare with a year earlier?

In August 2024, 83.4% of 338 departures left on time and 0.0% were cancelled, against 79.5% and 0.5% in August 2025.

Provenance

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