Climate, Weather, and Hanging Rock

CLIMATE AND WEATHER - what's the difference?

Climate and weather are the two aspects of meteorology.

The weather is a description of conditions over a short period of time - a "snapshot" of the atmosphere at a particular time. Climate, on the other hand, is the sum or synthesis of all the weather recorded over a long period of time. It tells us the average or most common conditions, (the mean temperature, the prevailing wind...) or extremes (the greatest rainfall, strongest wind...) or counts of events (the number of rainy days) or probabilities (how likely are three consecutive hot days in January?) Our example below makes the weather/climate difference clearer.

PICNIC AT HANGING ROCK - an illustration of the difference between weather and climate

Weather: (quote from the book*) "Everyone agreed that the day was just right for the picnic to Hanging Rock - a shimmering summer morning warm and still, with cicadas shrilling all through breakfast...." (Valentine's Day, 1900 at the Appleyard College for Young Ladies, near the village of Macedon in Victoria, Australia.)

Climate: The schoolgirls probably didn't know that there had been a meteorological observation site near Macedon since 1873. Records from the site show that the average maximum temperature in February is a rather pleasant 25 degrees Celsius, with an average of 7 rainy days for the month. On that basis, the girls could have calculated that the probability of a fine day for their picnic was about 75%, - much better than even odds. Their chances of an enjoyable day were looking good! * The Bureau wishes to thank Penguin Books Australia for permission to use the above extract from "Picnic at Hanging Rock" by Joan Lindsay

Bureau of Meteorology of Australia