Australian Standard AS 4055 divides the country into wind regions (A, B, C, D), then factors in terrain, shielding and topography to assign a specific wind classification. Most Bayside properties fall into Region A (non-cyclonic), but the final classification depends on four site-specific factors:
Wind Region
Bayside sits in Region A, with regional wind speeds around 155 km/h. However, proximity to Port Phillip Bay can push some sites into higher sub-classifications (A3-A5).
Terrain Category
Open coastal areas with limited obstructions get classified as Category 1.5 or 2. If your property sits on an exposed cliff-top in Sandringham with clear bay views, you’re likely in a more severe category than a Hampton property sheltered by neighbouring homes.
Shielding
Two rows of houses surrounding your property provide “full shielding.” One row equals “partial shielding.” A property directly facing the bay with no windbreaks? No shielding, which raises your classification.
Topography
Cliff-top properties in areas like Red Bluff Lookout face additional wind acceleration. A gentle slope increases wind speed by 5-15%, whilst a steep escarpment can double it.
For most Bayside homes, this results in a classification of N2 or N3 (non-cyclonic classifications requiring structures to withstand specific design wind speeds). Properties on exposed cliff tops or directly facing the bay may require N4 classification.