Charles M. Schulz - Sonoma County in May 2026

83.2%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 May 2026, reporting carriers scheduled 589 domestic departures from Charles M. Schulz - Sonoma County (STS). 83.2% left less than 15 minutes late and 82.9% reached their destination on time; 0.3% were cancelled.

Nationally that month, 77.1% of flights departed on time and 77.6% arrived on time, so STS departures were 6.1 points above the national departure figure.

A year earlier, in May 2025, the airport had 455 departures with 79.3% leaving on time: a change of +3.9 points, with flights up 29%.

Flights arriving at STS that month were on time 83.9% of the time (590 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, late-arriving aircraft 44%, air carrier 37% and national aviation system 18%.

On time 82.9%
Arrived 15+ minutes late 16.3%
Cancelled 0.3%
Diverted 0.5%

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

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

Measure	May 2026	May 2025	STS, 12 months to Jul 2026	All reported flights, May 2026
Departed on time	83.2%	79.3%	80.4%	77.1%
Arrived on time	82.9%	75.2%	78.8%	77.6%
Cancelled	0.3%	0.0%	1.7%	0.9%
Average departure delay (late minutes only)	12.5 min	12.5 min	13.2 min	16.0 min
Scheduled departures a day	20	15	16	20,391
Scheduled departures	589	455	5,714	611,735

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
OO SkyWest Airlines	421	71%	82.2%	5.8 min	0.5%
WN Southwest Airlines	108	18%	84.3%	-1.9 min	0.0%
AS Alaska Airlines	49	8%	93.9%	-9.4 min	0.0%
AA American Airlines	11	2%	45.5%	25.8 min	0.0%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
STS–SAN	Santa Rosa to San Diego	125	80.0%	9.2 min	0.8%
STS–BUR	Santa Rosa to Burbank	85	80.0%	2.4 min	0.0%
STS–PDX	Santa Rosa to Portland	70	88.6%	-4.4 min	0.0%
STS–LAS	Santa Rosa to Las Vegas	62	85.5%	4.9 min	0.0%
STS–SNA	Santa Rosa to Santa Ana	62	90.3%	-3.7 min	1.6%
STS–PHX	Santa Rosa to Phoenix	59	72.9%	12.3 min	0.0%
STS–LAX	Santa Rosa to Los Angeles	58	81.0%	4.8 min	0.0%
STS–SEA	Santa Rosa to Seattle	31	100.0%	-11.9 min	0.0%
STS–ONT	Santa Rosa to Ontario	12	91.7%	2.2 min	0.0%
STS–DFW	Santa Rosa to Dallas/Fort Worth	11	45.5%	25.8 min	0.0%
STS–PSP	Santa Rosa to Palm Springs	9	100.0%	-11.9 min	0.0%
STS–DEN	Santa Rosa to Denver	5	60.0%	17.8 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), May 2026.

Delay causes

BTS cause category	Share of delay minutes	National, May 2026	Minutes
Air carrier	36.9%	33.0%	2,455
Late-arriving aircraft	43.9%	40.4%	2,919
National Aviation System	17.9%	20.5%	1,188
Extreme weather	1.0%	6.0%	65
Security	0.3%	0.1%	19

6,646 delay minutes on 96 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 May 2026?

83.2% of 589 scheduled domestic departures left less than 15 minutes late, and 82.9% reached their destination on time. The national figures that month were 77.1% and 77.6%.

How does that compare with a year earlier?

In May 2025, 79.3% of 455 departures left on time and 0.0% were cancelled, against 83.2% and 0.3% in May 2026.

Provenance

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