Perth and Fremantle not only have a modern Mediterranean-style culture, but the climate to match. That is cool, wet winters and hot, dry summers. Sun protection is essential, especially in summer, so get yourself a wide-brimmed hat and wear a highly-rated sunscreen. Spring (September to November) and Autumn (March to May) are the pleasantest times of the year, with bearable temperatures and manageable rainfall.
Average daily temperatures and rainfall for Perth throughout the year are:
The variety of the landscapes and enormous geographical variance in WA means that there is no ‘right’ time of the year to visit. However, it’s a good idea to avoid high summer in the north and deep winter in the south, unless you like to see places at their extremes. Perth’s Mediterranean climate means that, despite some exceptional days during summer (Dec-Feb), the weather is suitable most of the year for whatever activity you choose.