Melbourne Metropolitan Area and Environs in May 2013:

City rainfall slightly less than that usually received.

  • Rainfall: average to below average
  • Maximum temperature: above average for most sites
  • Minimum temperature: near average for most sites

In Melbourne, overnight minimum temperatures were warmer than those usually experienced and averaged 9.8 °C, which was 1.1 °C warmer than normal.

That the overnight temperatures in Melbourne are higher than those in most surrounding localities is a consequence of the city being under the influence of the effect of urbanisation (cities are usually warmer than their rural surroundings, especially at night, because of heat stored in bricks and concrete and trapped between close-packed buildings).

Daytime maximum temperatures were warmer than those usually experienced and averaged 18.1 °C, which was 1.4 °C warmer than normal.

Total rainfall for the month was 36.6 mm, this being slightly less than that usually recorded (normal 55.9 mm, percentage of normal received 65%).

Records

Some sites had their highest May temperature on record.

Some sites had their lowest May mean daily minimum temperature for at least 10 years.

Extremes in May 2013
Hottest day 27.2 °C at Laverton RAAF on the 9th
Warmest days on average 18.4 °C at Avalon Airport
Coolest days on average 17.1 °C at Cranbourne Botanic Gardens
Coldest day 12.1 °C at Coldstream on the 22nd
Coldest night -2.3 °C at Coldstream on the 6th
Coolest nights on average 4.3 °C at Coldstream
Warmest nights on average 9.8 °C at Melbourne Regional Office
Warmest night 16.6 °C at Scoresby Research Institute on the 12th
Warmest on average overall 13.9 °C at Melbourne Regional Office
Coolest on average overall 10.8 °C at Coldstream
Wettest overall 85.2 mm at Cerberus
Wettest day 23.8 mm at Coldstream on the 17th
Highest wind gust 94 km/h at Melbourne Airport on the 3rd

Record highest May temperature
Highest temperature
in May 2013 (°C)
Previous warmest
for May
Years of
record
Average for
May
Cranbourne Botanic Gardens 25.4 on the 9th 25.2 on the 1st in 1997 24 16.3
Cerberus 25.6 on the 9th 25.5 on the 8th in 2002 22 16.5



Record lowest May mean daily minimum temperature
Mean daily minimum
temperature
for May 2013 (°C)
Previous coolest
for May
Years of
record
Average for
May
Cerberus 7.4 = 7.4 in 2003 21 8.3

Summary statistics for May 2013
Maximum temperatures
for May
(°C)
Minimum temperatures
for May
(°C)
Rainfall
for May
(millimetres)
Mean for
May
2013
Diff
from
average
Highest for
May
2013
Mean for
May
2013
Diff
from
average
Lowest for
May
2013
Total for
May
2013
Average
for
May
Rank of
May
2013
Fraction of
May
average
Avalon Airport 18.4 +1.3 26.1 8th 6.9 -0.6 1.7 29th 25.0 35.4 average 71%
Bundoora (Latrobe University) 17.3 +0.7 24.9 9th 7.4 -0.5 2.0 23rd 25.2 51.4 low 49%
Cerberus 17.2 +0.7 25.6 9th 7.4 -0.9 1.5 22nd 85.2 69.5 average 123%
Coldstream 17.4 +1.0 24.8 10th 4.3 -1.1 -2.3 6th 60.2 64.7 average 93%
Cranbourne Botanic Gardens 17.1 +0.8 25.4 9th 7.8 -0.6 3.0 24th 76.9 64.6 high 119%
Essendon Airport 17.7 +1.6 25.9 9th 8.2 +0.5 2.2 28th 32.2 49.2 average 65%
Laverton RAAF 18.0 +1.2 27.2 9th 7.9 +0.2 2.2 6th 30.8 46.6 average 66%
Melbourne Airport 17.7 +1.1 26.2 9th 8.0 -0.3 2.1 6th 25.6 40.0 average 64%
Melbourne Regional Office 18.1 +1.4 25.5 9th 9.8 +1.1 4.9 24th 36.6 55.9 low 65%
Moorabbin Airport 17.8 +0.9 25.9 9th 7.9 -0.7 1.7 6th 47.0 70.2 low 67%
Scoresby Research Institute 17.3 +1.1 24.9 9th 7.7 -0.5 1.4 6th 62.6 88.3 low 71%
Viewbank 17.6 +0.6 25.1 9th 7.5 -0.2 0.9 23rd 38.8 52.1 low 74%

Notes

A Monthly Climate Summary is prepared to list the main features of the weather in Melbourne using the most timely and accurate information available on the date of publication; it will generally not be updated. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.

This statement has been prepared based on information available at 12 pm on Monday 3 June 2013. Some checks have been made on the data, but it is possible that results will change as new information becomes available.

Averages are long-term means based on observations from all available years of record, which vary widely from site to site. They are not shown for sites with less than 10 years of record, as they cannot then be calculated reliably.
The median is sometimes more representative than the mean of long-term average rain.

The Rank indicates how rainfall this time compares with the climate record for the site, based on the decile ranking (very low rainfall is in decile 1, low in decile 2 or 3, average in decile 4 to 7, high in decile 8 or 9 and very high is in decile 10).
The Fraction of average shows how much rain has fallen this time as a percentage of the long-term mean.

The ACORN-SAT dataset is being used for temperature area averages from December 2012 onwards. The major change from earlier datasets is that the ACORN-SAT dataset commences in 1910, rather than 1950, and hence rankings are calculated using a larger set of years.



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