2019 new hottest and driest year

At Manilla, NSW, in the twenty years from 2000, the year 2019 was the hottest and the driest, overtaking the year 2018.

Climate logs Manilla 20-years

Climate records kept at 3 Monash Street, Manilla from April 1999 yield these eight graphs of climate variables. The graphs on the left (red) show heat and those on the right (blue) show moisture.
These graphs show the figures for calendar years, not for seasons.
In general, the temperatures in this 20-year record rose, with a pause between 2004 and 2012. Moisture peaked about 2010.
At Manilla, a sudden rise in temperature and fall in rainfall happened after 2017, having been much slower before that.
Dashed horizontal lines mark the normals for the decade from April 1999.

Left column graphs (red)

Yearly Mean Maximum Screen Temperatures

Day temperatures are shown by the mean maximum temperature in the Gill-type thermometer screen. The year 2019, at 27.91°, had the hottest days by far. The year 2018 had 27.13°, and 2002 and 2014 were almost as warm.The coldest days were in 2008 (24.57°) and 2010 (24.60°), followed by 2001 and 2011.
The 4th-order trend line shows a minimum about 2010, followed by a rapid rise.

Yearly Mean Screen Temperatures

This graph shows warmth in general, as in the study of global warming. Daily maximum and daily minimum temperatures are averaged. The year 2019 was the warmest (19.83°), followed by 2018, 2014, and 2009. The coolest year in this century was 2008 (17.19°), followed by 2001, 2011, and 2012.
The 4th-order trend line shows near-constant temperature from 2000 to 2011, followed by a rapid rise.

Yearly Minimum Screen Temperatures

Night temperatures are shown by the mean minimum temperature in the thermometer screen. While 2018 had not had very warm nights, 2019, at 11.75°, had warmest nights as well as days. The next warmest were in 2014, 2010 and 2009. Years with nights cooler than 10° on average were 2012, 2008, 2006 and 2001.
The 4th-order trend line shows a rise from 2000 to 2008, then near-constant temperature to 2014, followed by a rapid rise.

Yearly Subsoil Temperatures

Yearly temperatures in the subsoil (at 750 mm depth) hardly related at all to air temperatures read in the Gill Screen. The best match is in 2008, when the subsoil temperature was lowest (19.00°), as were the screen mean (17.19°) and the screen maximum (24.57°).
[Note that world temperature was low late in 2007.]
Continue reading

House Thermal Mass Works in Summer Too

House temperature ranges diagram

My house at Manilla, NSW, is in a climate with temperatures that are extreme, but comfortable on the average. To reduce extreme temperatures indoors, the house contains more than a hundred tonnes of thermal mass within a shell of insulation.
The “thermal mass” is the materials, such as bricks, stones, concrete, earth or water, that have high thermal capacity (See Notes below): they take in and give out a lot of heat.
Many people, who can see that having thermal mass inside a house will help to keep it warm in winter, think that the thermal mass will make it hard to keep the house cool in summer. They see many brick and brick-veneer houses in which thermal mass is exposed to the intense heat of the summer sun. In that case, thermal mass material does no good.

In this graph, I have used my last twelve months of temperature data to show the benefit of well-insulated thermal mass in summer as well as in winter.
Outdoor temperature in this year went as low as minus 4.0° Celsius and as high as plus 43.7°: a range of 47.7°. Continue reading

Damp end to cloudy May 2010

The daily weather logWeather log May 2010

Dry weather with warm days and cool nights lasted most of the month. On the 13th the early morning Dew Point of -6.3° set a record for low humidity in May. The seven-day average temperature was quite low in the second week. Nine mild frosts (usually 6) all came about this time. By the 25th there had been only 57 mm of rain in 14 weeks: an average of barely 4 mm per week. A serious rainfall shortage was developing, despite months of cloudy weather.
Late in the month nights became very humid and warm. Mornings had fog on the 18th and 22nd and mist (visibility one kilometre) on the 27th and 31st. Three days had more than 5 mm of rain. In all, the month had 8 rain days, totalling 28.0 mm.

 Comparing May monthsClimate May 2010

This was the cloudiest May in the 11-year record. The mean maximum temperature and the mean average were normal. The mean minimum was up, reducing the daily temperature range, and the mean Dew Point was down.
The rainfall of 28.0 mm is near the median for May (51st percentile). It is below the long-term average of 40 mm, but no May total has beaten the average since 1998! Rainfall totals for groups of months show just one serious shortage. The 15-month total (538 mm) is now down to the 7th percentile.

Subsoil Temperature

Both graphs now include subsoil temperature measured at 750 mm depth. There the temperature barely changes during a day. It changes slowly with the seasons. Usually it ranges from 26° in February to 14° in July.
As observed in Manilla, the  subsoil temperature does not relate to the normal average temperature of the air in a simple way. In May, it stays about five degrees warmer; in other autumn and winter months it is less than five degrees warmer. In spring and summer it is almost the same as the normal average air temperature.
In autumn 2007 the subsoil temperature was nearly two degrees warmer than usual; in autumn 2008 it was one degree cooler than usual. This is a puzzle, because the average air temperature did not change so much.

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.