What is the best time of year to visit Perth ?.
Taking into account the weather and what's going plus a visit to the wineries in the South.
I'm thinking about going in November or possibly January/February next year.

Hi Lesg,
Perth weather in summer can be very hot so if you are averse to being outdoors in 37 degrees C plus weather, wait until early fall or late spring. This summer has been fairly mild (only a few days approaching or exceeding 40 degrees C) and all that sunshine and relatively low humidity makes perfect touring weather imho.

February can sometimes exceed temperatures in January so I'd suggest November, though any of the months mentioned would be divine for a southern winery sojourn. Though, when wouldn't! Margaret River is gorgeous and the wines fantastic, be sure to venture out for early dinners though if you're in the mood for good food to off-set the wine. Restaurants appeared to close around 9ish when I was last there! Cafe Fiore was particularly memorable. Enjoy!

Hi,
Spring is wonderful in Perth. All the wildflowers are spectacular.
Cheers

September-November would be very good times to come. Our spring begins 1st September and summer starts 1st December. Summer is high season in Margaret River and some places will charge peak rates at that time. (I prefer the SW in the cooler months myself as do many from Perth). If you come in spring as kaiesha said, you will get to see our spectacular wildflowers and see the SW bathed in green, be able to stay in cosy cabins or chalets with the fire on after a pleasant day visiting wineries.

The weather in the SW is somewhat cooler than Perth though, especially in the evenings. Pick your type of holiday (swimming etc or more walking type activities) and match it to the months

Typo re the delicious Margaret River restaurant - please amend that to Cafe Forte. The food melts in the mouth! Mind you WA's south west is a gem for vegetarian and gourmet palates throughout. And if you do happen to make it all the way down to Albany, which should be significantly cooler, do try the Harvest Moon for relaxed views of the harbour and great food and chess boards.