Warmer nights and cooler days

Record high sea surface temperatures in the tropics from June to December 2010 also contributed to high minimum temperatures in this region, as sea surface temperatures moderate minimum air temperatures over coastal and island regions.

For instance, at Horn and Coconut islands in the Torres Strait, the previous Queensland August record high minimum temperature of 25.4 °C was surpassed on 24 separate occasions during 2010, peaking at 26.8 °C at Horn Island on 19 August. Similarly, record warm ocean waters off Western Australia's west coast led to the hottest year on record for southwest Australia.

High rainfall and associated cloud cover generally kept Australian maximum temperatures below average during both La Niña events. Conversely, increased cloud cover and damp soils meant less heat was lost during the nights, resulting in above-average minimum temperatures for most of Australia during the 2010–11 event, and for southern Australia during the 2011–12 event.

The maps below show mean maximum (daytime) and minimum (night-time) temperature deciles, where blue tones indicate below-average temperatures and orange tones indicate above-average temperatures.

2110

Record warm ocean waters off the west coast of Western Australia was associated with the hottest year on record for southwest Australia during 2010.

2010–11 La Niña

The 2010–11 La Niña was associated with much cooler than average daytime temperatures and much warmer than average night-time temperatures.


Daytime temperatures (July 2010 to March 2011) – below to very much below average across most of inland Australia

Night-time temperatures (July 2010 to March 2011) – above average to highest on record for large parts of the country

2011–12 La Niña

The 2011–12 La Niña was associated with cooler than average daytime temperatures in some areas, but the deviation from normal was not as marked.

Daytime temperatures (October 2011 to March 2012) – below average in some parts of inland Australia, above average in some coastal regions

Night-time temperatures (October 2011 to March 2012) – above average across parts of southern Australia and the north, below average inland