Lets see, you know its summer when:
-You start to complain about the pool being too hot
-Its too hot to go outside without a water bottle/sunscreen
-You sweat when doing nothing
-Cicadas/noisy birds
-You start to see reptiles are being more active
-The spiders come out of hiding from the cold
-It feels like you are boiling
-You wear shoes to the beach and only take them off to get in the water
-The rats start to become more active in the walls (not just summer where i am)
-The Possums are more active
And many more, isn't Australia the best place, the reason we are rude to foreigners is because we don't want to be slugged with the most deadliest place on earth because nearly all of the tourists have died from our native wild life.
Almost forgot:
-You start to see drop bears when camping
EDIT: Just found this as well
http://www.buzzfeed.com/simoncrerar/pictures-that-prove-australia-is-the-craziestI love Australia (from the other side of an unbreakable wall)