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.

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