Following a chilly day on Saturday, Sydney's temperatures are on the rise once again. After Fridays top of 23 degrees in the city, thunderstorms and a cloudy southerly change cooled conditions quickly. Saturday only reached a maximum of 15.3 degrees in the city; the coldest September day it has seen in 7 years. Terry Hills' top of 13.2 was its coldest in September day in 10 years while Richmond joined the city in having its coldest September day in 7 years, failing to climb above 15.2 degrees. Today (Sunday), the skies have cleared and the Sydney Basin is enjoying temperatures back into the low twenties. Only three other times has the maximum temperature at Observatory Hill risen above 23 degrees, then fallen below 15.5 degrees the next day, only to return above 21 degrees the day after. These run of days were in September 1913, October 1931 and most recently in August 1946. Temperatures in Sydney are going to continue to rise until Wednesday, when the mercury could rise well into the mid-twenties in the city and the high-twenties out west. With the lack of any strong cool changes, Sydney will likely stay 3-5 degrees above the September average (20.1 degrees) until next weekend.