According to ABC News New South Wales is on track to hit hottest March on record after coolest summer in 11 years.
What's behind the March heatwaves?
The reason autumn is doing its best interpretation of summer is complex.
It is essentially a combination of factors playing out simultaneously, including:
- La Niña's demise combined with a break in the monsoon has allowed a lengthy stretch of sunny skies to generate a broad mass of hot air over northern and central Australia
- The westerly winds which circumnavigate Antarctica have expanded during the past few weeks, extending to our southern latitudes and dragging the hot interior air across NSW.
- Water temperatures in the Tasman Sea are at nearly 27C, theoretically warm enough to support a tropical cyclone. This means that, even when winds are onshore, it is still warmer than normal.
The most surprising aspect is the westerlies, which have spent the past few warm seasons banished to the Southern Ocean.
The recent absence of westerly winds was a critical factor in Sydney's record wet 2022, a year dominated by moist easterly winds and rain….
It is definitely unseasonably warm in Yamba – on land and in the ocean. The hottest day to date this month was Saturday 18th March which was a day where minimum air temperature was 22.6°C and maximum air temp 34.4°C, with a relative humidity of 93% at 9am.
By comparison March 2022 saw highest minimum and maximum air temperatures at a milder 22.6°C and 29.6°C respectively, with a relative humidity of 97% at 9am.
According to the Australian Bureau of Meteorology the average daytime air temperature in the month of March for the 146 years between 1877 to 2023 was minimum 19.3°C and maximum 26.1°C, with a relative humidity of 80% at 9am.
