Sydney has just experienced its longest spring dry spell on record. While drizzle dampened large swathes of the Sydney Basin this morning, the city's rain gauge at Observatory Hill managed to evade any recordable rainfall. A number of northern and western suburbs recorded rainfall during the 24 hours to 9am today, including 3.5mm at Belrose, 2.4mm at Terrey Hills, 1.6mm at Long Reef and 1.4mm at Penrith. The smallest amount of rainfall Australia's rain gauges are able to record is 0.2mm. As drizzle is composed of very small water droplets that are less than 0.5mm in diameter, it usually fails to deliver enough water into the gauge and goes unregistered in official observations. However, drizzle is certainly noticeable if you get caught without an umbrella on the way to work. Sydney's 0mm observation during the 24 hours to 9am today is the city's 27th consecutive rainless day. This is now Sydney's longest spring dry spell on record, beating the 26 day spring dry spells from 1988 and 1951. It is also Sydney's longest run of rainless days in four years for any time of year. The city's longest dry spell on record lasted for 47 days from July 18th to September 2nd in 1995. With only 0.2mm of rain recorded at Observatory Hill between the start of September and 9am today, Sydney is currently experiencing its driest start to spring on record.