Latest Southern Oscillation Index values

SOI values for 21 May 2012

Average for last 30 days	0.8
Average for last 90 days	0.2
Daily contribution to SOI calculation	-2.7

Monthly average SOI values

February	0.8
March	2.3
April	-6.2

Note: Calculated using the 1887–1989 base period. This information is usually updated every weekday at 4:30pm (AEST), public holidays excluded.

Southern Oscillation Index (SOI)

• Recent (preliminary) Southern Oscillation Index (SOI) values
• SOI data files
• Graphs of monthly SOI values and SOI Phases, 1899-current