As an example of the relatively dry period that Perth has been experiencing in recent decades, the breaking of the April rainfall record is the first occurrence of a monthly rainfall record in any autumn or winter month since Perth’s July rainfall record was exceeded in 1958.
April (mid autumn) isn’t usually such a wet month in Perth, but in April last year 76.4mm of rain fell – more than double the average amount. The wettest day had 40mm. This April had 153.6mm of rainfall – five times the average. The main culprit was the day 58.6mm of rain fell. This didn’t mean we lacked sunshine or 28°C+ days (6 of them). Rain fell on only 13 days of April. Halfway through April April’s average rainfall was 31.1mm, but because of April 2008’s deluge, the average has now risen to 38.8mm.
This April’s rainfall counteracted January’s absence of any rain at all. January is a dry month with an average of 17.6mm, but there’s usually a summer thunderstorm. (Sydney was having their own deluge over summer caused by a La Niña event, which has now ended.)
Despite Perth’s month-long inundation, some parts of Australia aren’t doing so well. This week I met a man from Adelaide when out walking Sheeba the dog who told me Adelaide would like some of the rain we’ve been having.
During the last two years drought conditions have continued in parts of WA’s south west and north along the coast towards Shark Bay, northern South Australia and in a band stretching from the Bight coast of SA across much of Victoria to the western slopes and plains of southern NSW, southeast Queensland, and Tasmania. This includes serious to severe deficiencies in rainfall, right through to the lowest on record.
Areas in the Geraldton Sandplain, 400km north of Perth have been receiving the lowest on record. My friend works in canola (rape seed) research and last year she took a trip to Geraldton to visit canola farms. None of the farms could grow a crop last year because there was no rain. Rainfall deficiencies spanning the previous two years have been lessening every month this year in the area of the Geraldton Sandplain, so perhaps their drought is coming to an end.