Wednesday, 6 January 2016 - Monthly Climate Summary for Sydney - Product code IDCKGC15L0

Sydney in December 2015: Warm, stormy end to the year

Sydney had a warm December in 2015, with severe storms causing heavy rain, hail and a tornado on the 16th.

• Storms and tornado cause damage on the 16th
• Above average maximum and minimum temperatures
• Close to average rainfall

Rainfall was generally average to above average during December, with 96.6 mm recorded at Sydney Observatory Hill, 24% above the historical average. The rain fell over 12 days, normal for December, with most of the rain falling during a period of onshore flow following a cold front on the 21st. Observatory Hill recorded 63.8 mm of rain during the 48 hours to 9 am on the 23rd, with two-day totals as high as 121 mm at Glenorie. Thunderstorms also produced locally heavy rain on the 9th and 16th, with 58 mm recorded at Randwick for the 24 hours to 9 am on the 17th. There was an average of 7.9 daily hours of sunshine measured at Sydney Airport, average for December.

The most significant weather event of the month occurred on the 16th, when a series of severe thunderstorms crossed the city. A category F2 tornado damaged several properties and the desalination plant in Kurnell, with a wind gust of 213 km/h recorded, the strongest wind gust ever recorded in New South Wales. The thunderstorms also produced heavy rain and localised flash flooding, with 53 mm in 30 minutes in Rose Bay. The heavy rain collapsed a roof in Bondi Junction Westfield, while hail of up to 3 cm in diameter was reported in several locations in southeast Sydney including Cronulla.

The average mean temperature at Observatory Hill was 0.9 °C above average. Maximum temperatures were above average across the city, while minimum temperatures were above average at Observatory Hill and Sydney Airport but average to below average elsewhere. Temperatures were warmest during the start and middle of the month, with average to below average temperatures towards the end of the month.

There were 18 days with temperatures 25 °C or higher (average 14 days), with four reaching at least 30 °C (average 3 days). In western Sydney, five days reached at least 35 °C at Parramatta (average 3 days), with several stations recording temperatures over 40 °C on the 20th. Eight nights reached at least 20 °C at Observatory Hill (average 4 nights), with 23.6 °C on the 21st, the warmest December night since 24.9 °C was recorded on 23 December 2000.

Extremes Records Summaries Daily observations Important notes the top

Extremes Records Summaries Daily observations Important notes the top

Extremes Records Summaries Daily observations Important notes the top

Extremes Records Summaries Daily observations Important notes the top

Extremes Records Summaries Daily observations Important notes the top