On Wednesday, September 9, 2026, four Bay Area locations set daily high temperature records: San Rafael at 104°F, downtown Oakland at 97°F, San Francisco International Airport at 94°F and Half Moon Bay at 83°F, according to KQED. Temperatures ran 10 to 20 degrees above normal. For Palo Alto homes, the heat wave tested air conditioners that had barely run all summer.
The records
KQED reported on September 10, 2026 that four locations broke daily records the day before:
| Location | High on Sept 9, 2026 |
|---|---|
| San Rafael | 104°F |
| Downtown Oakland | 97°F |
| San Francisco International Airport | 94°F |
| Half Moon Bay | 83°F |
SFO and Half Moon Bay sit on the Peninsula, which usually stays cooler than inland areas. When the coast hits records, the bayside cities between them, including Palo Alto, see some of the hottest afternoons of the year.
Heat did not stop with summer
KQED reported on September 29 that above-average temperatures were expected into mid-October, and the City of Palo Alto issued its own heat advisory notice on October 2. Read the October advisory details.
What we saw in Palo Alto homes
Our calls during heat waves follow a pattern: failed capacitors and contactors on outdoor units, frozen coils from dirty filters, clogged condensate drains that shut systems off, and older systems that run all day without reaching the setpoint. Many Palo Alto homes were built before central air, so second floors and rooms under flat roofs struggle first.
Getting ready for the next one
- Schedule a maintenance visit in spring, before the first hot week
- Replace filters monthly during heat waves
- If your AC is over 15 years old, compare repair against a heat pump, which also replaces gas heat and qualifies for CPAU rebates
- Keep our number handy: 650-460-3483, answered 24/7
Sources
- KQED: Bay Area heat wave breaks records in these 4 cities (Sept 10, 2026)
- KQED: Summer is over, but the Bay Area’s heat is just getting started (Sept 29, 2026)
Published by the ComfortFlow HVAC Palo Alto team. Event date: .