Monday, 2 July 2012 - Monthly Climate Summary for Sydney - Product code IDCKGC15L0

Sydney in June 2012: Two East Coast Lows bring wind and rain to Sydney

• Wettest June since 2007
• Warm days in the city, but coldest in five years
• East Coast Lows hit the city

Extremes Records Summaries Important notes the top

Rainfall - Wettest June since 2007

Sydney Observatory Hill recorded 244.2 mm of rain during June, well above the historical average of 130.5 mm and the wettest June since 2007 (510.6 mm). The rain fell over 15 days, close to normal for June (12 days), of which 11 exceeded 5 mm (average 5 days).

The majority of the rain fell as an East Coast Low (ECL) developed off the north coast of NSW on the 11th, with two days of heavy rain across the NSW coast. Sydney Observatory Hill recorded a 48 hour total of 125.8 mm to the 12th, the highest 2-day total in June since the severe ECLs of June 2007, with up to 176.6 mm over 48 hours at Dover Heights in eastern Sydney.

Further rain fell as a surface trough crossed the state at the beginning on the month, with 27.4 mm on the 3rd and 11.2 mm on the 4th. This was followed by falls of 19.2 mm in the city and up to 57.2 mm at Collaroy on the 6th as an ECL developed in the trough and moved northward. A period of moist easterly windflow triggered additional showers in eastern parts of the city at the end of the month.

Temperature - Warm days in the city, but coldest in five years

The average maximum temperature at Sydney Observatory Hill during June was 17.7 °C, 0.8 °C above the historical average, with temperatures generally below average at shorter-record sites in western Sydney. This is the coolest June since 2007 (16.8 °C) and was associated with above average rainfall and below average sunshine during the month. Three days dropped below 15 °C, half the historical average but the most since June 2007. This included a maximum of 13.7 °C on the 26th, the coldest June day since 13.2 °C on 19th June 2007.

Minimum temperatures were also slightly warmer than normal across the city, with an average of 9.7 °C at Observatory Hill, 0.4 °C above normal. There were 13 nights above 10 °C, slightly above normal for June (11 nights), with the coldest night reaching 6.4 °C; on average 1-2 nights drop below 6 °C during June. The average temperature at Sydney Observatory Hill during June was 13.7 °C, 0.6 °C above normal.

Wind - East Coast Lows hit the city

The prevailing wind direction at Sydney Airport during June was northwesterly in the mornings (60%) and southerly to westerly in the afternoons (73%), normal for June.

There were two strong wind days, below normal for June (4 days), both associated with an East Coast Low that crossed the city on the afternoon of the 5th. This brought short-lived heavy rainfall and very strong wind gusts, reaching 104 km/hr at Sydney Airport, 117 km/hr at Port Botany and 128 km/hr at Wattamolla. This was the strongest wind gust at Sydney Airport since 107 km/hr during an ECL in August 2010, and the strongest June winds since 106 km/hr in during an ECL in 1978.

Mean winds remained above 50 km/hr at Sydney Airport from 4 pm on the 5th to 7am on the 6th, resulting in roof damage and power outages. This is the longest period above 50 km/hr since the ECL of 6-9 June 2007, and only the 20th event with such sustained winds since records began in 1939. The system also resulted in large waves and beach erosion, with maximum wave heights off Sydney exceeding 10 m for eighteen hours between 6pm on the 5th and midday on the 6th, reaching almost 14 m overnight.

A second ECL developed off the north coast of the state the following weekend, bringing heavy rainfall to Sydney but weaker wind and wave impacts, with a maximum wind gust at Sydney Airport of 54 km/hr on the 11th.

Other Phenomena

The average daily sunshine at Sydney Airport was 5.3 hours, below average for June (6 hours). There were no thunderstorms, normal for June, with one fog reported at the airport.

Extremes Records Summaries Important notes the top

Extremes Records Summaries Important notes the top

Most values are the precipitation in the 24 hours to 9 am on the day indicated. Days marked with »» are part of a longer accumulation, which is marked like this on the final day. Values over 100 mm have been rounded to the nearest whole millimetre. Days marked with - have a rainfall report of zero; days left blank have no rainfall report (which often indicates no rain fell).
This table is very wide; you may have to scroll sideways to see all the days, and you may need to set the paper to 'landscape' to print.

Extremes Records Summaries Important notes the top