Tag Archives: summer

January “Coolth” in a House without Air-Conditioning

Posted in Indoor Climate by

I have now 15 years of January average temperature data for my house at Manilla, North-west Slopes, NSW. These graphs show how the house temperature relates to the outdoor (or ambient) maximum, mean, and minimum temperatures.Regression graphs of indoor on outdoor temp in the hottest month

The house is not too hot and not too cold

Solar-Passive House from the NE.

House at Monash St Manilla from NE

In January (the hottest month) the rooms* in this solar-passive house do not heat up much during the day, nor do they cool down much at night. Since the indoor temperature always rises and falls just one or two degrees from the mean, only the mean is shown. Green lines on the graphs, which are drawn to pass through the middle of each cloud of data points, show by how much (on the average) the indoor temperatures have differed from the outdoor maximum, mean, and minimum temperatures. On the middle graph the green line shows that the rooms have been 0.5° cooler than the mean temperature outdoors. The left graph shows that the rooms have been 8.2° cooler than the daily maximum outdoor temperatures. The right graph shows that the rooms have been 7.3° warmer than the daily minimum overnight temperatures.

The design of the house aimed to protect those living there from excessive summer heat. It may seem that reducing the mean temperature by only half a degree is a failure. Not so! The January mean temperature at this site (26.1°) is near the middle of the adaptive comfort zone for this month, and so is the indoor mean temperature (25.6°). The house succeeds in keeping the indoor temperature comfortable in the heat of the day, when that outdoors is an uncomfortable 34 degrees. The high thermal mass that achieves this has the unfortunate result that the minimum indoor temperature overnight (not shown) is some five degrees warmer than the outdoor minimum. However, on average, it is still a comfortable 23.5 degrees. (Curiously, no-one knows the best room temperature for sleep.) Continue reading →

2013-14: Third Driest Summer

Posted in Manilla NSW, Season Weather by

Weather log summer 2013-14.

After a cool start, this summer had no more cool weather. There were five warm spells 3° to 4° warmer than normal. Days were particularly warm, with a new 21st century record high of 43.7° set on 3/1/14. During warm spells, nights were also warm, but often 17° cooler than the days. The air was phenomenally dry in early January, with morning dew points (usually 14°) falling below zero three times. There were only 14 rain days (usually 21), and the heaviest fall of 18.8 mm was a 21st century record low for summer.

Taking average values, this summer had the highest daily maximum temperature this century: the value of 34.3° beats the 34.1° of 2005-6. However, the daily mean of 26.1° does not beat the 26.3° of 2005-6. By contrast, the summer of 2011-12 was the coldest, by day and by night. The total rainfall of just 84.8 mm makes this the third driest summer in the 131-year record, after 1929-30 (66 mm) and 1964-5 (70 mm). The summers of 1999-2000 and the two following were also very dry (125 mm, 158 mm, 137 mm) but this summer had not only less rain but also very much drier air and a wider daily range of temperature. Both the low dew point, 8.6° , and the wide daily temperature range, 16.4°, were record values. The earlier dry summers were less cloudy, however.Climate summer 2013-14.

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.

Summer 2012-13 hot in parts

Posted in Manilla NSW, Season Weather by

Weather log summer 2012-13Summer was marked by a heat wave in January, similar to that in November 2009. It was not quite so hot, except that the hottest day set a 21st century record of 43.2°. The season also began very hot, but there were other times that were very cool, especially in February.

Twelve days had exceptionally low humidity, below 10%, with a record low value of 4% on 11th January.
There were 22 rain days, which is normal.

In contrast to the very low temperatures last summer, this summer’s temperatures were normal. At 37% cloudy mornings, this summer was a bit cloudier than normal (31%). Morning dew points set a new summer record low of 12.2°, beating the record set last year.
The rainfall total of 260.6 mm beats the average of 228 mm. It is in the 65th percentile.Climate summer 2012-13.

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.

2011-12 Summer Cold and Wet

Posted in Manilla NSW, Season Weather by

Weather log summer 2011-12.In the whole of this summer, only 3 days went over 35° (usually 23) and only 5 nights went over 20° (usually 19).

The smoothed curves of temperature reached up as high as normal only twice. In early January both days and nights were normal. Later, with persistent rain around the 1st of February, nights warmed to normal, but days were extremely cold.
All the mean daily temperatures were the lowest in 13 summers: maximum 28.9°, mean 22.2°, and minimum 15.4°. Summer ’07-’08 had been just slightly warmer.
Daily temperature range this summer (13.5°) was very narrow, as in ’07-’08 and ’10-’11; all wet summers with very cloudy skies. Strangely, this cloudy wet summer had very low humidity, with morning Dew Point (12.7°) the lowest on this record.
While this was a very wet summer, at 333 mm, it was only the 19th wettest (86th percentile), and not much wetter than summers 4, 6, and 8 years ago.Climate summer 2011-12.

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.

2010-11: Summer very cloudy again

Posted in Manilla NSW, Season Weather by

Weather log summer 2010-11As in summer 2008-09, day temperatures got steadily warmer. From 8° below normal in mid-December they rose to 5° above normal in early February, and crashed to below normal before recovering. As in 2008-09, the lower temperature in mid-February came with a day of very heavy rain.

As is normal, there were two days over 40° and none below 20°.

The mean daily mean temperature was normal but, due to cloud cover, the mean maximum was rather low (31.6°) and the mean minimum rather high(18.1°), reducing the mean daily temperature range to 13.6° (normally 15.1°).
This summer was the cloudiest in this record, at 54% cloudy mornings (more than four eighths of cloud), just beating the summer of 2007-08 (53%). Given that Manilla summers averaged only 31% cloudy mornings from 1999 to 2008, this is a big change indeed.
The total rainfall of 270 mm is above the long-term summer average of 225 mm. It is in the 68th percentile.Climate summer 2010-11

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.