Driest Air in August 2018

Tree with a face painted on it.

Painted Box Tree

Temperatures were not far from normal during the month, except that the weekly mean was 3.2° low about the 20th. There were 20 frosts (normally 15), but the coldest morning fell only to -2.7°.
Some rain fell early in the month. Later, with the cold nights, the air became extremely dry, reaching a new record early morning dew point of -12.1°. Abruptly, the 25th brought overcast and high humidity, then rain and fog. Estimated rain was 9.0 mm on the 26th, 10.2 mm on the 27th, and 0.8 mm on the 28th.

Weather log August 2018.

Comparing August months

The month was rather cool, with a mean (10.7°) that was 0.4° below normal, and cold nights (2.0°), 1.1° below normal. Measures of moisture were only slightly low, except that humidity was extremely low, setting a new record mean early morning dew point of -4.2°.
Moderate falls of rain totalled 28.2 mm (estimated), which is at the 40th percentile for August.
I have reported the shortage of rainfall separately ( “Drought Sixth Month: August 2018”) .

Climate in August months.


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.  The record was again defective in August 2018. Seven daily readings were missing. On one of the missing days (the 27th) my rain gauge showed 10.2 mm, the highest daily reading for the month. I have substituted my non-standard gauge readings for all days of both July and August.

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

3-year trends to April 2017

Parametric plots of smoothed climate variables at Manilla
“Cold-Arid ‘Glacial'”

Climate trends to April 2017

April raw anomaly data (orange)

In terms of anomalies, April 2017 was even cooler than March, but much more arid. Anomalies of both daily maximum and daily minimum temperature fell by more than three degrees from February values, (They plot near the margins of the lower left graph.)
On most of the graphs, raw anomaly values for April plot towards the top left corner. Rather than moving along the top-right-to-bottom-left axis of “Droughts and flooding rains”, they combine low temperature and aridity as happened in ice ages.

 Fully smoothed data (red)

The most recent fully-smoothed data is for October 2016. Following a winter that was cool and moist, October shows a climate becoming steadily warmer and drier.
The smoothed anomaly of daily minimum temperature, which had hit a record high value in May 2016, approached a minimum value that was near normal.
Subsoil temperature anomaly was still falling rapidly, and was certain to reach a new record low smoothed value in November.


Note:

Fully smoothed data – Gaussian smoothing with half-width 6 months – are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange. January data points are marked by squares.
Blue diamonds and the dashed blue rectangle show the extreme values in the fully smoothed data record since September 1999.

Normal values are based on averages for the decade from March 1999.* They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 * Normal values for rainfall are based on averages for the 125 years beginning 1883.