NSW annual air quality statement 2023: climate

Summer 2022–23 was drier-than-average for the state. Rainfall totals in January were 20% below long-term average, followed by a much larger rainfall deficit in February (56%). The state's north-east was driest, with very much below-average rainfall across the Northern Tablelands and Northern Rivers.

Both January and February saw warmer-than-average days, with state-averaged maximum temperatures 1.33°C above average. Summer nights were cooler-than-average for large parts of the state.

Bureau of Meteorology New South Wales seasonal climate summary: Summer 2022–23

Autumn 2023 was also drier-than-average for the state, with rainfall totals 31.6% below average. There were substantial falls in late March over most of the slopes west of the Great Dividing Range, and in the state's northern and southern parts in April.

While daytime (maximum) temperatures were warmer across large parts of the state, nights were average to cooler-than-average. The statewide maximum temperature for autumn 2023 was 0.69°C above the long-term average, while the minimum was 0.54°C below average.

Bureau of Meteorology New South Wales seasonal climate summary: Autumn 2023

Statewide winter 2023 rainfall totals were 28.2% below-average. The state's far west did receive above-average rainfall totals in June, but dry conditions persisted in general. By the end of August, areas with severe rainfall deficits developed along the state's east coast, extending from northeast New South Wales to the far southeast border.

Winter 2023 was the state's warmest since records began in 1910, with daytime temperatures 2.33°C above long-term average. Winter nights were also warmer, with average to above-average minimum temperatures.

Bureau of Meteorology New South Wales seasonal climate summary: Winter 2023

The spring statewide rainfall totals were 16.4% below the long-term average. The state had its second-driest September after 2017. Rainfall was below-average for areas along the Great Dividing Range and the state's north-west. In late November, a deep low-pressure system brought several days of widespread rain. Many sites had their highest November daily rainfall on record, including areas along the state's far southeast border.

Spring 2023 was the state's second warmest since records began, with daytime temperatures 3.20°C above the long-term (1961 to 1990) average. Areas in the southeast and northwest saw record average daytime temperatures for spring. Overnight temperatures were also 1.2°C above the long-term average.

Bureau of Meteorology New South Wales seasonal climate summary: Spring 2023

Rainfall in December was 4.4% above average for the state, due to continuing thunderstorms, particularly for southern and eastern New South Wales. Many sites had either their highest December rainfall totals or their highest December daily totals on record.

December temperatures were above to very much above-average for most of the state, with maximum temperatures 2.18°C above average, and minimum temperatures 1.98°C above average. A heatwave affected the state between 2 to 10 December, when daytime temperatures peaked at least 10°C above-average at some sites. At Sydney Airport, the maximum temperature on 9 December 2023 (43.2°C) was well above its long-term monthly average (25.9°C), an 85-year record.

Bureau of Meteorology New South Wales monthly climate summary: December 2023