Sydney weather is formed from a temperate climate with warm summers and mild winters. The city enjoys more than 340 days of sun each year. Average minimum temperatures in the winter months of June through to August are at their lowest. The summer season is from December through to February when the highest temperatures are recorded. During the summer months the beaches are packed with locals and visitors trying to escape the heat and lack of humidity.
Due to the El Nino - Southern Oscillation (ENSO, a global ocean-atmosphere phenomenon coupled with La Nina), and the East Coast Lows (low pressure depression) Sydney is sometimes hit with hail storms and flash flooding. These major storms happen once every few years and cause massive damage. ENSO is associated with droughts and flash flooding and it cycles through every 3 to 8 years.
As you can see from the table below, rainfall is reasonably well spread across the year. The start of the year sees the easterly winds dominate and rainfall is slightly higher at this time. Sydney never has to deal with cyclones.
Sydney Monthly Rainfall