After the first week, each week in December was very hot, reading up to 5.9° above normal. Both days and nights were hot, but only one record was set: 42.2° on the 21st was the hottest December day. That was well below the record hot day of 44.9° set on 11/2/17.
Twenty mornings were cloudless which was twice the usual number. Smoke from mainly coastal bushfires reduced visibility to 15 km or less from the 8th to the 25th. Early in the month, rain fell on three days, the highest reading being 12.4 mm on the first day.
Comparing December months
This month broke 21st century records for December mean monthly temperatures. The mean minimum of 18.7° just beat 18.6° of December 2009, the mean average of 27.6° easily beat 26.1° last year, while the mean maximum of 36.5° was far above last year’s 33.9°.
On balance, indicators of moisture make this the driest December of the century. Rainfall, at 19.6 mm, was lower than any but December 2006 (18.8 mm), and the dew point was equal lowest with 2013. This month had by far the fewest cloudy mornings (10%) and the widest daily temperature range (17.8°).
I will report separately on the on-going drought that continues to break low-rainfall records at durations of 15-months and longer.
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. Recording resumed on 20 July 2019.
My estimates of early morning dew point have drifted anomalously low. From August 2019, I use data from the Tamworth Airport published graphs.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.