Charles M. Schulz - Sonoma County in April 2026

86.0%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 April 2026, reporting carriers scheduled 558 domestic departures from Charles M. Schulz - Sonoma County (STS). 86.0% left less than 15 minutes late and 84.1% reached their destination on time; 0.0% were cancelled.

Nationally that month, 79.1% of flights departed on time and 78.9% arrived on time, so STS departures were 6.9 points above the national departure figure.

A year earlier, in April 2025, the airport had 363 departures with 80.2% leaving on time: a change of +5.8 points, with flights up 54%.

Flights arriving at STS that month were on time 85.7% of the time (560 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, late-arriving aircraft 47%, air carrier 26% and national aviation system 22%.

On time 84.1%
Arrived 15+ minutes late 15.9%
Cancelled 0.0%
Diverted 0.0%

Every scheduled departure from STS in April 2026, judged by arrival at the destination.

April 2026 against a year earlier, the airport's year and the nation

Measure	Apr 2026	Apr 2025	STS, 12 months to Jul 2026	All reported flights, Apr 2026
Departed on time	86.0%	80.2%	80.4%	79.1%
Arrived on time	84.1%	76.3%	78.8%	78.9%
Cancelled	0.0%	0.3%	1.7%	0.9%
Average departure delay (late minutes only)	10.5 min	11.9 min	13.2 min	14.5 min
Scheduled departures a day	19	12	16	19,931
Scheduled departures	558	363	5,714	597,919

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
OO SkyWest Airlines	437	78%	84.2%	1.4 min	0.0%
WN Southwest Airlines	79	14%	82.3%	7.9 min	0.0%
AS Alaska Airlines	30	5%	83.3%	1.8 min	0.0%
MQ Envoy Air	12	2%	91.7%	-9.3 min	0.0%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
STS–SAN	Santa Rosa to San Diego	112	75.0%	5.1 min	0.0%
STS–LAX	Santa Rosa to Los Angeles	72	87.5%	0.8 min	0.0%
STS–BUR	Santa Rosa to Burbank	70	82.9%	3.6 min	0.0%
STS–SNA	Santa Rosa to Santa Ana	60	88.3%	-0.3 min	0.0%
STS–PHX	Santa Rosa to Phoenix	56	83.9%	7.7 min	0.0%
STS–LAS	Santa Rosa to Las Vegas	54	88.9%	3.4 min	0.0%
STS–PDX	Santa Rosa to Portland	50	88.0%	-7.4 min	0.0%
STS–ONT	Santa Rosa to Ontario	30	90.0%	-4.2 min	0.0%
STS–SEA	Santa Rosa to Seattle	30	83.3%	1.8 min	0.0%
STS–PSP	Santa Rosa to Palm Springs	21	81.0%	10.2 min	0.0%
STS–DEN	Santa Rosa to Denver	3	100.0%	-14.0 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), April 2026.

Delay causes

BTS cause category	Share of delay minutes	National, Apr 2026	Minutes
Air carrier	25.6%	33.5%	1,501
Late-arriving aircraft	47.3%	40.4%	2,771
National Aviation System	22.4%	21.0%	1,313
Extreme weather	4.7%	5.0%	277
Security	0.0%	0.1%	0

5,862 delay minutes on 89 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 April 2026?

86.0% of 558 scheduled domestic departures left less than 15 minutes late, and 84.1% reached their destination on time. The national figures that month were 79.1% and 78.9%.

How does that compare with a year earlier?

In April 2025, 80.2% of 363 departures left on time and 0.3% were cancelled, against 86.0% and 0.0% in April 2026.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for April 2026; 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.