Tuesday, 1 May 2012 - Monthly Climate Summary for Sydney  - Product code IDCKGC15L0

Sydney in April 2012: Warm, wet April for Sydney

• Above average rainfall.
• Above average temperatures.
• Warmest start to April in over 20 years.

Extremes Records Summaries Important notes the top

Rainfall

Sydney Observatory Hill recorded 148.2 mm of rain during April, slightly above the historical average of 126.4 mm but drier than April 2011 (206.2 mm), although a temporary data loss on the 18th means true totals may have been higher. The rain fell over 9 rain days, below the April average of 13 days, of which three exceeded 10 mm. Around the Sydney region, most stations recorded above average rainfall, including the wettest April since 1990 at Bankstown and Glenorie.

Most of the rain fell between the 17th and 19th, as a coastal low pressure trough caused several days of persistent rain across the NSW coast. Sydney Observatory Hill recorded a 48 hour total of at least 104.8 mm to 9am on the 19th, the wettest such period in April since 165.4 mm fell on 11 April 1998. Daily falls reached 100 mm at Turramurra on the 19th and 95 mm at Glenorie on the 18th, with most of the city recording at least 100 mm during the event. Two-day totals reached 177.8 mm at Turramurra, the wettest April event since 30 April - 1 May 1988. The heavy rain was associated with flash flooding throughout the city, particularly in the coastal suburbs and the north shore, as well as minor spillage from the Warragamba Dam.

Temperature

Sydney Observatory Hill recorded an average maximum temperature of 23.6 °C during April, 1.2 °C above the historical average, with temperatures above average across the metropolitan region. Eleven days exceeded 25 °C during the month, double the historical average of 5 days, reaching 28.3 °C on the 7th, the warmest April day since 30.7 °C on 23 April 2010. Temperatures were particularly warm at the start of the month with seven consecutive days above 25 °C, only the third time on record for April and the first since 1977. The first nine days of April were thus the 6th warmest on record and warmest since 1986, before the temperature dropped to just 19.1 °C on the 10th.

Minimum temperatures were also above average throughout Sydney, with 15.5 °C at Observatory Hill, 0.8 °C above the historical average. Temperatures were warmest at the start of the month, with eight consecutive nights above 16 °C, reaching 20.1 °C on the 8th. This was followed by a cold snap with two consecutive nights below 11 °C on the 10th and 11th, the coldest period this early in April since 12-13 April 1994. There were four nights below 11 °C during the month, the most since 2006, although no nights dropped below 10 °C. The average temperature at Observatory Hill was consequently 19.5 °C, 1 °C above average.

Wind

The wind direction during April was variable, with 33% of 3pm winds at Sydney Airport SSE-SSW but 50% of 3pm winds N-E, with a lower proportion of E-SE winds than normal for April. There were six strong wind days reported at the airport, above the historical average of 4 days and the most since 2007. The strongest wind gusts reached 72 km/hr on the 9th and 10th, with the strongest gust anywhere in the metropolitan region reaching 78 km/hr at Port Botany on the 25th.

Other phenomena

Sydney Airport recorded an average of 7.1 hours of bright sunshine during April, close to the historical average of 6.9 hours. Three thunderstorms were reported at the airport, the most since 2007, with four storms anywhere in the Metropolitan region, and reports of hail on the 8th. Two fog days were reported at the Airport, on the 20th and 21st, the most in April since 2007, with fog covering much of the city on the morning of the 20th.

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