Monday, 1 March 2021 - Seasonal Climate Summary for New South Wales - Product code IDCKGC25R0

New South Wales in summer 2020-21: wet and cool

Summer 2020–21 saw above average rains across most of New South Wales, overall rainfall was 29% above average and the wettest summer since 2011-12. Daytime temperatures were below average across the state, and it was the coolest summer since 2011–12. The Northern Rivers region received very heavy rain, with flooding and coastal erosion, from low pressure systems in mid-December and late February.

Wettest summer since 2011-12

• Summer rainfall was above average across New South Wales except in the far west of the state.
• For the state as a whole summer rainfall was 29% above the 1961–1990 average at 215.7 mm, making it the state's wettest summer since 2011–12.
• December saw widespread above-average rainfall totals, and it was the wettest December for the state as a whole since 2010.
• The Northern Rivers District was affected in mid-December by a slow-moving coastal trough and weak low-pressure system.
• Much of the north-east of the state had its wettest December since national records began in 1900.
• January rainfall was close to average overall, but with widespread above-average totals across the south.
• February rainfall was above average, with widespread rain from the Upper Western to Riverina districts and in northern coastal areas.
• A Tasman Low affected northern coastal areas from 18 to 23 February, with widespread showers and heavy rain in some parts.
• Some eastern sites had their highest summer daily rainfall on record.
• Many sites from the Mid-North Coast to the Northern Rivers district had their highest total summer rainfall on record or their highest total for at least 20 years.

Coolest summer since 2011-12

• The New South Wales mean temperature for summer 2020–21 was 0.03 °C above the 1961–1990 average, making it the state's coolest summer since 2011–12.
• Daytime temperatures were below average across most of the state, and 0.19 °C below average overall.
• Night-time temperatures were below average in the south of the state, and above average in the north and along the coast.
• The highest recorded temperature was on the first day of summer, with Brewon AWS near Walgett reporting 48.0 °C, the second-highest temperature ever for December in New South Wales.
• An inland trough and associated cloudband saw Cobar Airport and Bourke Airport report their coldest summer day on record on 21 December.
• A stationary high pressure system in the Tasman Sea combined with an inland trough brought very hot air across parts of the state from 22 to 26 January.
• Heatwave conditions in late January were severe to extreme in some regions, but no temperature records were set.

A significant rain event for the Northern Rivers district

• A slow-moving coastal trough, with associated weak low pressure system, moved along the coast in the New South Wales and Queensland border region from 11 to 17 December.
• The system brought widespread heavy rain to the Northern Rivers district, with damaging winds, abnormally high tides and dangerous surf conditions along the coast.
• Flash and riverine flooding was reported for the Tweed, Clarence, Richmond/Wilsons and Bellinger rivers.
• There was major coastal erosion at numerous beaches, most notably at Byron Bay.
• The most intense rainfall occurred along the New South Wales and Queensland border on 12 December, with sites on either side recording daily totals of 300–450 mm.
• Multi-day rainfall totals across the event were the highest in the area since at least April 2017.
• Weekly rainfall totals to 9am 18 December exceeded 200 mm across the Northern Rivers, with over 400 mm in some areas.

Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top

Maps
	Observed	Anomaly	Decile rank
Total rainfall
Mean daily maximum temperatures
Mean daily minimum temperatures

Click on a map to show it full size in a pop-up window

* note: there are gaps in the historical record at this site, so it is possible a higher value has gone unreported

* note: there are gaps in the historical record at this site, so it is possible a lower value has gone unreported

Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top