Recent climate
December rainfall was below average to average for the SWLD. December maximum temperatures were very much above average and minimum temperatures were average to above average. Rainfall since 1 November has been below decile 3 for much of the SWLD.
In December 2021, the atmospheric pressure was higher than normal over the SWLD.
In December 2021, the Indian Ocean sea surface temperatures north-west of Western Australia were warmer than normal.The January to March 2022 SST forecast, by the Bureau of Meteorology, indicates SSTs are likely to remain warmer than normal, north of WA.
The Southern Annular Mode (SAM), also known as the Antarctic Oscillation (AAO), describes the north–south movement of the westerly wind belt that circles Antarctica, dominating the middle to higher latitudes of the southern hemisphere. The SAM index is currently positive and is predicted to remain so until the end of January. In a positive SAM phase, the belt of westerly winds contracts towards Antarctica. A positive SAM phase in summer has no influence on SWLD rainfall. For more information, see the Bureau of Meteorology’s Climate Driver Update.
The Indian Ocean Dipole (IOD) is neutral. A neutral IOD has little influence on Australian climate.
The La Niña conditions continue in the tropical Pacific. Climate models suggest this La Niña will persist until the late southern hemisphere summer or early autumn, 2022. Based on past La Niña events, summer rainfall is expected to be average for the SWLD.
The table below summarises climate conditions of the past month and three-months for the SWLD, and can indicate what is likely to occur in the near future if climate conditions follow the current pattern.
| Climate indicator | Past month | Past 3 months |
|---|---|---|
| SWLD Rainfall | Below average | Average to above average |
| SWLD Mean Temperature | Above average | Below average to average |
| SWLD atmospheric pressure | Higher | Higher |
| Indian Ocean Sea surface temperature | Warmer | Warmer |
| El Niño/Southern Oscillation (ENSO) | La Niña | La Niña |
| Indian Ocean Dipole (IOD) | Neutral | Neutral |
| Southern Annular Mode (SAM) | Positive | Positive |