ASCE 7-16 · WIND SPEED MAPS
Read the right map for your design wind speed
ASCE 7-16 publishes basic wind speeds as ultimate, strength-level 3-second gusts at 33 ft in Exposure C — mapped across the contiguous US and special wind regions.
FIGURES 26.5-1 SERIES
Four maps, one per Risk Category
Risk Category does not multiply the speed — it picks which map you read. Higher category means a longer return period (MRI) and a higher mapped wind speed.
Risk Category I
Low hazard to human life — minor agricultural and storage structures.
300-yr MRIRisk Category II
Standard occupancy — homes, offices, retail and most buildings. The baseline map.
700-yr MRIRisk Category III
Substantial hazard — large assembly, schools, jails and power facilities.
1,700-yr MRIRisk Category IV
Essential facilities — hospitals, fire/police, EOCs, shelters, critical utilities.
3,000-yr MRIILLUSTRATIVE — NOT TO SCALE
Where speeds run highest
A simplified picture of the contiguous US: hurricane-prone Atlantic and Gulf coasts carry the highest mapped speeds, easing inland toward the interior. Read actual values off the published map for your location.
Schematic only — colors show relative magnitude, not contour values. Always read the published figure for your exact site.
FIELD WORKFLOW
How to read the maps
Three moves take you from a pin on the map to the design speed V you carry into the calculation.
1 · Find your location
Pin the project site on the contiguous-US map by latitude/longitude or city and county.
STEP 12 · Pick the Risk-Category map
Classify the building, then open the matching map — I, II, III or IV — for the right return period.
STEP 23 · Read the contour V
Read the basic wind speed off the nearest isopleth; interpolate between contour lines when the site falls between them.
STEP 3DON'T MISS THIS
Special wind regions
Some areas are shaded as Special Wind Regions — mountain gaps, gorges, canyons and coastal promontories where local channeling can drive speeds above the surrounding contours.
In these regions the map contour is a starting point, not the answer. A site-specific meteorological analysis by a qualified engineer is required. Examples in ASCE 7-16 include the Columbia River Gorge, Wasatch Front canyons and certain coastal headlands.
SKIP THE MANUAL READ
Get the speed without the interpolation
Look up ASCE 7 wind speeds by location instead of measuring contour distances by hand.
KEEP READING
Related wind speed guides
ASCE 7-22 Wind Speed Maps
The newer MRI-based maps and what changed from 7-16.
7-22Wind Speed by Location
Find the design wind speed for your specific project site.
LOOKUPBasic Wind Speed Explained
A full guide to the basic wind speed parameter V.
CONCEPTWind Speed Zones Guide
How wind speed zones work across ASCE 7 editions.
OVERVIEW