It’s been a very dry start to winter in Perth this year. I usually don’t have to water my garden at all from sometime in May on, but in the last two weeks I’ve been watering my vegies every couple of days.
The average rainfall for June in Perth is 139.6mm from the Bureau of Meteorology. If we’re going to get anywhere near the June average its going to have to rain an awful lot in the next ten days, because so far we’ve had 9.2mm on only four June days. Rain is forecast tomorrow and for the following week, so it might happen.
Australia is prone to drought and the El Niño event of the 2006/07 summer caused a severe drought. Some areas of Australia received above average rainfall in autumn and this has caused some relief. Other areas have ended the drought with too much rain. New South Wales is about to experience their third major storm this month.
The storms that hit the Hunter Valley region and the Central Coast several weeks ago left nine people dead and a clean-up bill that is already running into the hundreds of millions of dollars.
This map of the past three months rainfall in Australia is for rain in Autumn and the west of Western Australia is mainly pink and red, with lower than average rainfall. Perth is in a white area (average rainfall) because the lower rainfalls of March 6.2mm and May were added to April’s rainfall of more than double the average amount at 76.4mm. This high monthly rainfall was caused by one day when 40mm of rain fell, more than April’s monthly average.
Perhaps this means Perth’s rainfall has just gone a bit wonky.
NB. I mentioned El Niño above, but it affects eastern and western Australia differently. While it’s often linked to reduced rainfall in eastern and northern Australia; Western Australia, not being on the Pacific Ocean, won’t necessarily experience drought at the same time. El Niño is a natural phenomenon which is separate to human induced climate change, although the severity of El Niño events might be affected by climate change.
A few years ago I read a book called El Niño: The Weather Phenomenon that Changed the World by Ross Couper-Johnston (2000, Hodder & Stoughton). It describes El Niño events through history (determined by looking at historical weather events, etc.) and the differences between El Niño and its opposite La Niña, which (I have a vague recollection) causes more problems for Western Australia. Maybe I need to look at it again to fix that vagueness.