CALIFORNIA · SAN FRANCISCO COUNTY (CITY-COUNTY)
At the Tip of the Peninsula, the Wind Rips Straight Through the Gate
San Francisco pairs a moderate basic wind speed with brutal site variability: Pacific-fed gusts funneled through the Golden Gate, hilltop speed-up, and a skyline where seismic usually leads but wind still rules the cladding.
CYAN · PENINSULA WIND CLIMATE
Why a "Moderate" Map Number Lies About This Site
The map value sits in the 100–115 mph band for Risk II, but San Francisco's terrain rewrites it block by block. Exposure and topography do the heavy lifting here.
Funneled Through the Gate
Westerlies off the Pacific compress through the strait and slam the Sunset, Richmond and Presidio shoreline.
VENTURI EFFECTHilltop Speed-Up
Twin Peaks, Nob, Russian and Telegraph Hills trigger Kzt >1.0 near the crest, easing back to 1.0 away from the feature.
Kzt TOPOBay Meets Open Ocean
Embarcadero and bay shoreline lean Exposure C; Ocean Beach and Lands End can push Exposure D over open water.
B · C · DMicroclimate Whiplash
Fog and wind shift dramatically across a few blocks, so one exposure call rarely covers a whole district.
SITE-SPECIFICSeismic usually governs the frame — wind governs the skin. Sitting between the San Andreas and Hayward faults, SF lateral design is dominated by seismic. But ASCE 7-22 wind cases are still mandatory and routinely control curtain walls, windows, roofing and components & cladding. Exact mph varies by site.
VIOLET · SF DBI SUBMITTAL CHECKLIST
What a Permit Set Owes the Department of Building Inspection
Six things every San Francisco wind-load package needs before plan review will sign off.
Confirm the Map Speed
Pull the Risk-Category basic wind speed (100–115 mph band for Risk II) for the exact address.
STEP 1Justify the Exposure
Document whether the site is urban B, bayfront C, or open-ocean D — and defend the upwind fetch.
STEP 2Run the Topo Factor
Apply Kzt per ASCE 7-22 §26.8 for hilltop, ridge and escarpment sites; flat ground stays at 1.0.
STEP 3Separate MWFRS & C&C
Produce both main-frame pressures and the localized component & cladding pressures that often govern here.
STEP 4Stamp by a CA PE/SE
Calculations carry a California-licensed PE or SE seal; complex towers may face independent peer review.
STEP 5Tie It to CBC + SF Code
Reference the California Building Code with San Francisco amendments and ASCE 7-22 as adopted.
STEP 6CYAN · DOWNTOWN & SOMA TOWERS
Where Slender High-Rises Make Wind Talk Back
In the Financial District and South of Market, dynamic wind behavior and pedestrian-level comfort enter the conversation even where seismic still controls the frame.
Wind-Tunnel Territory
Slender or irregular towers often warrant wind-tunnel testing instead of code-only pressures.
SLENDER GEOMETRYVortex & Crosswind
Tall buildings get checked for vortex shedding and dynamic crosswind response, not just static load.
DYNAMIC EFFECTSStreet-Level Comfort
Ground-level wind acceleration around new towers is reviewed for pedestrian comfort downtown.
PEDESTRIAN WINDCYAN · STATEWIDE & OFFICIAL REFERENCES
Keep Reading Up and Down the Coast
Statewide context, the official jurisdictions, and the agencies that license the engineers sealing these calculations.
California Statewide
How CBC and ASCE 7-22 set the baseline every California city builds on.
STATE GUIDEAll State Requirements
Compare adopted ASCE editions and design wind speeds across every U.S. state.
50-STATE INDEXSF Dept. of Building Inspection
The permitting authority for San Francisco structural plan review.
SF DBIEMERALD · RUN THE NUMBERS
Pin the Exposure, Topo and Pressures for Your SF Address
Drop in a San Francisco address and the calculator resolves the Risk-Category map speed, B/C/D exposure, Kzt, and MWFRS plus C&C pressures into a PE-ready ASCE 7-22 report for SF DBI.