Winter 2018 had the driest air

A gum-tree blowing in the wind

Wind-blown Gum-tree

Temperatures varied widely, especially at night. In both mid-July and mid-August, the weekly mean night temperatures were more than 4° low. At these times, the air was extremely dry.
Early in July night temperatures were nearly 4° high, while late in July it was the day temperatures that were more than 4° high. The daily temperature range was almost 21° in mid-July, having been less than 13° in mid-June.
There were 16 rain days, but the highest reading (estimated) was only 10.2 mm.

Weather log for winter 2018

Last winter’s report had been headlined: “Dry air in winter 2017”. This winter was even drier by all measures. In particular, the mean early morning dew point set a new record of -3.0°. The best match in this century is the winter of 2002. Both had warm days, cold nights, wide daily temperature range, little cloud and low dew point.
The total rainfall of 42 mm makes this the 9th driest winter on record, displacing winter 2002, which had 44 mm. (The year 1888 had the lowest winter rainfall total: 6 mm. However, daily readings are missing. The next lowest was 1946, with 29 mm, then 1972 and 1982, both with 32 mm.)

Climate for winter 2018


Data. A Bureau of Meteorology automatic rain gauge operates in the museum yard. From 17 March 2017, 9 am daily readings are published as Manilla Museum, Station 55312.  These reports use that rainfall data when it is available. During this winter season 20 daily readings were missed, including several days with significant falls of rain. I have used my own readings for the whole season.

All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Dry Air in Winter 2017

Photo of red Eucalyptus flowers

Eucalyptus leucoxylon in winter

This winter had remarkably dry air. The lowest early morning dew point was -10.0°, and the winter mean was -0.5°. Both were record low values. Through the season, the dew point got further and further below the early morning temperature, ending five degrees lower.

Daily maximum and minimum temperatures were near normal. However, they were more than a degree cooler than in the recent winters of 2009 and 2013.

Graphical log for winter 2017

With dry air came a wide daily temperature range of 16.3°, second only to 17.5° in the winter of 2002. It also brought sunny weather, with only 32% cloudy mornings. While that was near the average for my “normal” decade 1999-2008, it was lower than in any recent winter. The winters of the last decade, 2007-2016, were much more cloudy, averaging 45% cloudy mornings. Winter 2016 had 53%!

There were four brief spells of rain this winter, none with heavy rain. They were spaced about seventeen days apart. That sequence had begun in autumn, with heavier falls then. After the 4th of August there was no rain at all.

The total rainfall of 89.8 mm was at the 27th percentile, well below the winter average of 125 mm. Five recent winters had similar amounts of rain: 2000 (98 mm), 2001 (107 mm), 2003 (102 mm), 2004 (97 mm) and 2006 (104 mm). Two were much drier: 2002 (44 mm) and 2011 (55 mm).

Climate for winter 2017


Data. A Bureau of Meteorology automatic rain gauge operates in the museum yard. From 17 March 2017, 9 am daily readings are published as Manilla Museum, Station 55312.  These reports use that rainfall data when it is available. All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.