India Basic Wind Speed Map — IS 875 (Part 3):2015
Search any of 197+ Indian cities or click anywhere to see the basic wind speed (Vb) and design implications per IS 875 (Part 3):2015 Fig. 1. Six zones from 33 m/s (interior peninsular India) to 55 m/s (cyclone-exposed coast). Apply k1, k2, k3, k4 factors for final design wind pressure.
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About IS 875 wind speed zones
IS 875 (Part 3):2015 is the Indian Standard for wind loads on buildings and structures. The basic wind speed Vb (3-second gust at 10 m height in open terrain) varies from 33 m/s (south-central peninsular interior) to 55 m/s (coastal cyclone-exposed strip).
Design wind pressure: pz = 0.6 × Vz² where Vz = Vb × k1 × k2 × k3 × k4. The map gives you Vb. The factors k1–k4 vary by site (life class, terrain category, topography, cyclone proximity).
k4 cyclone factor
For cyclone-exposed coastal regions (within 60 km of designated cyclone-prone coast), k4 amplifies Vb. Values per IS 875 Part 3 Cl. 6.3.4: 1.00 (general industrial), 1.15 (residential), 1.30 (cyclone shelters, hospitals, lifelines). Combined with cyclone-zone Vb of 50 or 55 m/s, effective design wind speeds can exceed 70 m/s.
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IS 875 (Part 3):2015 — Wind Loads · Cyclone Zones map · Handbook: Wind Loads reference
Frequently asked questions
What is the basic wind speed in Mumbai?
Mumbai's basic wind speed Vb = 44 m/s per IS 875 (Part 3):2015 Fig. 1. Design wind pressure (10m height, terrain Cat 2): pz = 0.6 × Vz² ≈ 1.16 kN/m². Apply k1, k2, k3, k4 factors per Cl. 6.3.
What is the basic wind speed in Chennai?
Chennai's basic wind speed is 50 m/s with cyclone factor k4 = 1.30. The effective design wind speed is 50 × 1.30 = 65 m/s, giving pressure ~2.54 kN/m². East coast cities require cyclone factor amplification.
What is the cyclone factor k4 in IS 875?
k4 is the cyclone-importance factor applied within 60 km of cyclone-prone coastal regions. Values: 1.00 (industrial), 1.15 (residential), 1.30 (cyclone shelters, lifelines). Applied to industrial structures, lifelines, hospitals, schools per IS 875 Part 3 Cl. 6.3.4.
How is design wind pressure calculated?
Per IS 875 Part 3 Cl. 7.1: pz = 0.6 × Vz² (in N/m², where Vz = Vb × k1 × k2 × k3 × k4). Vb = basic wind speed from map; k1 = life factor (1.05 normal, 1.08 important); k2 = terrain × height factor; k3 = topography factor; k4 = cyclone factor. Final pz feeds force/cladding/component design.
Which cities have the highest design wind speed?
55 m/s — coastal Odisha (Puri, Brahmapur), AP coast (Visakhapatnam), Tamil Nadu coast, Andaman Islands. With k4 = 1.30 applied, effective design wind speed becomes 71.5 m/s.
Vb values follow IS 875 (Part 3):2015 Fig. 1. For boundary zones (where Vb transitions 33→39, 47→50, etc.) use the higher value as a conservative envelope. Reference only — final design should rely on the published standard and a qualified engineer.