Weather Watch | Unseasonal rain, heat

EXTREMES: Last week Hobart recorded its highest-ever May rainfall while Perth basked in balmy summer-like heat. Both are extraordinary weather events.
EXTREMES: Last week Hobart recorded its highest-ever May rainfall while Perth basked in balmy summer-like heat. Both are extraordinary weather events.

The past week has seen two major weather events which certainly look out of place across the nation as they occurred simultaneously.

On May 11 Hobart recorded 129.2mm, easily the wettest-ever May day in 177 years.

It was Hobart's wettest day since April 23, 1960 when 132mms fell. Other wetter days at Hobart were 147mm on June 7, 1954 and 156mm on September 15, 1957.

Conversely Perth has bathed in near-record summery heat.

The temperature reached 32.7 degrees last Saturday, May 12. Other high May temperatures occurred in 1886, 1907, 1928, 1953, 1972, 1980, 2002 and 2003.

Not once during any of these past occurrences in Perth did Hobart have exceptionally heavy rain at the same time.

However, a warm spell in early May 1962 in Perth saw heavy widespread rain in both Victoria and Tasmania during that month with maximum temperatures below the May normal. June 1962 was slightly warmer than May that year.

There have been more warm days in Perth. The mean maximum temperature to May 16 was 24.6 and this is the highest for the first half of May since 25.8 in 1962. 

There was a brief warm spell in our region about May 21, 1962, with heavy rain and storms until near the end of May; then came a long sequence of mild to warm days with N/NW winds for most of June of 1962 with frontal passages bringing near-average rain for the month.

Other very wet Mays in Hobart were 110mms in 1848, 150mm in 1882, 161.8mm in 1905, 116mm in 1923, 135.6mm in 1956 and 213.8mm in 1958. Three of these, 1848, 1882 and 1923 followed a dry spell for most of the previous 12 months.

I do not have records for 1848 except for Melbourne which show that the period May 1848 to January 1850 was extremely wet with major floods.

On May 11 Hobart recorded 129.2mm, easily the wettest-ever May day in 177 years.

The other two saw above-average rain for the rest of the year in our regions, while 1923 saw the general wetness continue well into the following summer.

High May temperatures in Perth have in the past given us a warm spell lasting about a week or so.

The recent cold snap suggests we will miss out this coming week but some warm days likely near the end of May or early June. The next rain event is anticipated about May 24 in the region.