December 2012 Hot, with Rain

The daily weather logWeather log December 2012.

As in November, most days this month were warmer than normal. The 1st, at 40.6°, was the equal hottest December day on this record, with 30/12/05.
Afternoon values of Relative Humidity fell to 7 percent on the 15th and 16th.
Rain was recorded on nine days, totalling 97.4 mm, with the highest reading 29.8 mm on the 26th.

 Comparing December monthsClimate December 2012.

Days this month, at 33.3°, were not quite as hot as those of December 2005 (33.7°). Nights this month were warm (17.5°), but not nearly as warm as those of December 2009 (18.6°). In stark contrast, December 2011 was several degrees cooler.
The mean early morning Dew Point of 11.7° shows the air is almost as dry as it was a year ago. Since then, the air has been even drier, with an extremely low morning Dew Point of 1.7° in October.
The sky was less cloudy than in any of the last five Decembers.
The rainfall of 97.4 mm is high, in the 72nd percentile for December. This defers all concerns about rainfall shortages: even the five-month total of 190 mm is in the 25th percentile.

The Year 2012

In 2012, rainfall was extremely high in February, April, and July, but extremely low in August and October. The total for the year (669 mm) was a little higher than the long-term mean of 652 mm, but a lot lower than last year’s 837 mm.
By other measures, Manilla’s climate drifted during the three years 2010, 2011 and 2012, from a humid coastal type to an arid inland type. In 2010 day temperatures had been very low (24.6 degrees), and night temperatures high (11.2 degrees), as would happen on the coast. By 2012, day temperatures had risen to normal (25.5 degrees), and night temperatures had fallen very low (9.6 degrees). A typical day in 2010 had the very narrow temperature range of 13.4 degrees, while a day in 2012 had a range of 15.9 degrees.
In the same way, 2010 had been extremely cloudy and humid, while 2012 had normal cloud and extremely low humidity. Subsoil temperature (750 mm) rose from a low value of 19.6° in 2010 to a record annual high of 21.6° in 2012.

Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Temperatures, including subsoil at 750 mm, and other data are from 3 Monash Street, Manilla.


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