Friday, 8 January 2021 - Annual Climate Summary for Greater Sydney - Product code IDCKGC55L0

Greater Sydney in 2020: wettest year in over 20 years

It was a wet year in Greater Sydney, with annual rainfall the highest since 1998 in the central city and since 1990 in many western suburbs. After an extremely hot start to the year, temperatures were above average but not as high as those of 2019.

A wet year in Greater Sydney

• Rainfall in 2020 was above average throughout Greater Sydney.
• At most locations, rainfall was 20% to 50% above the long-term average, although some coastal locations were closer to average.
• Some sites had their highest daily rainfall on record.
• Some sites, mostly sites which opened in the 1990s, had their highest total rainfall on record.
• Some sites had their highest total rainfall for at least 20 years. In particular, some locations in western Sydney had their wettest year since 1990.
• February was especially wet throughout Greater Sydney, with most sites receiving three to four times their average monthly rainfall. At Observatory Hill, it was the fourth-wettest February on record and the wettest month since June 2007.
• July was also significantly wetter than average.
• April was a very dry month, with Observatory Hill rainfall 77% below average, although the Aprils of 2018 and 2019 were even drier. September was also significantly drier than average.
• After February, seasonal rainfall was relatively close to average. Autumn, winter and spring were all within 20% of average at Observatory Hill, with autumn and spring slightly below average and winter slightly above.

Nights warmer than average

• Night-time minimum temperatures were above average in 2020 at most Greater Sydney locations, while daytime maximum temperatures were near average in the west and generally above average near the coast.
• Most sites were in the order of 0.5 °C above average for minimum temperatures, although larger differences from average occurred at some locations.
• Daytime maximum temperatures were generally cooler than those in 2019, whilst night-time minimum temperatures were similar to those of 2019.
• January was a hot month, with maximum temperatures 3 °C or more above average at some locations.
• Nights were warm in spring, with some sites, particularly in western Sydney, having their highest average spring minimum temperatures on record.
• Autumn was relatively cool, particularly in March. Average minimum temperatures at Observatory Hill for both March and autumn were the lowest since 2008, while March was the first month with minimum temperatures below the long-term average there since April 2017.
• Some sites had their highest temperature on record.
• Some sites had their warmest night (highest daily minimum temperature) on record.
• Some sites had their highest mean daily minimum temperature on record.
• Some sites in western Sydney had their highest mean daily minimum temperature for at least 20 years.

Sydney (Observatory Hill)

• Rainfall measured for 2020 at Sydney (Observatory Hill) was 1551.2 mm, 28% above the long-term average at the former Observatory Hill site.
• The exact total for 2020 is not known due to an equipment outage in September. Based on totals recorded during the outage at surrounding sites, it is estimated that 5 to 10 mm fell during the outage period in addition to the measured total of 1551.2 mm.
• This is the wettest year at this location since 1998.
• The mean daily maximum temperature for Sydney (Observatory Hill) was 23.5 °C.
• This is 1.7 °C above the long-term average at the former Observatory Hill site, but cooler than 2018 or 2019.
• The warmest day was 41.2 °C on 23 January, and the coolest day was on 7 August when the temperature reached 13.6 °C.
• The mean daily minimum temperature for Sydney (Observatory Hill) was 14.7 °C.
• This is 0.9 °C above the long-term average at the former Observatory Hill site.
• The coldest morning was 6.2 °C on 25 August, and the warmest morning was on 29 November when the minimum temperature was 25.3 °C.

A summer of heatwaves and floods

• Extreme heat affected Greater Sydney on a number of occasions early in the year. The most exceptional heat was on 4 January, when temperatures reached 48.9 °C at Penrith, the highest temperature ever recorded in Greater Sydney.
• Later in the year, on 28 and 29 November, Observatory Hill exceeded 40 °C on 2 successive days, only the second time this has occurred at that location at any time of year. Some Western Sydney sites experienced their hottest night on record on the 29th.
• Major fires which were burning in and around the Greater Sydney region at the end of 2019, continued through the first few weeks of 2020, until heavy rain fell in early February. Significant smoke pollution affected parts of the region at times.
• Heavy rain from 7 to 10 February resulted in significant flooding in parts of Greater Sydney. There was major flooding in the Hawkesbury-Nepean and Georges Rivers, with the Hawkesbury at North Richmond reaching its highest level since 1992.
• During the February event, Observatory Hill had 242.0 mm of rain in two days and 391.6 mm in four days, the highest such totals for any month since 1992 and 1990 respectively.
• A major hailstorm affected parts of Greater Sydney on 20 January, with hailstones of up to 6 cm in diameter and widespread damage reported.
• Several coastal lows affected eastern New South Wales in July and August. Whilst the most severe impacts were in the Illawarra and South Coast districts, Greater Sydney experienced heavy rain, particularly from 26 to 28 July, and some coastal erosion.
• The most significant snow of the winter in the Blue Mountains was on 22 August, with light falls reported at Blackheath and Katoomba.

Extremes Maps Records Summaries Important notes the top

Extremes Maps Records Summaries Important notes the top

* 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