March 2025

Southern Annular Mode (SAM)

The figure displays the SAM daily index (black line) and forecast summary (green line) (sourced 3 April 2025 from the Bureau of Meteorology).

The latest value can be found on the Bureau of Meteorology’s website.

Sustained values above +1 indicate a positive SAM event, whilst values below -1 indicate a negative event.

The Southern Annular Mode (SAM) refers to the north-south shift of rain-bearing westerly winds and weather systems in the Southern Ocean compared to their usual position. This indicator can be quite volatile and generally influences weather conditions on 1-to-3-week timescales.

Southern Annular Mode Daily Index and Forecast Summary
Sourced from the Australian Bureau of Meteorology
Image for Southern Ocean (Southern Annular Mode – SAM)