2018 hottest and driest

In the nineteen years 2000 to 2018, this last year was the hottest and the driest.

Climate logs 19 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. They do not show hot summers or cold winters. In particular, each summer spans two calendar years.
In general, the temperatures in this 19-year record rose, with a pause between 2004 and 2012. Moisture peaked about 2010.

Day Temperatures

Daily max temp, 19 years

Day temperatures are shown by the mean maximum temperature in the thermometer screen. The year 2018, at 27.13°, had the hottest days by far. Four other years with hot days were widely spread: 2002, 2009, 2014, and 2017. The coldest days were in 2008 (24.57°) and 2010 (24.60°), followed by 2001 and 2011.

Average Temperatures

Daily Mean Temp, 19 years.

This graph shows warmth in general, as is done in the study of global warming. For each day, the daily maximum and daily minimum temperatures are averaged. Then these values are averaged for each year. The year 2018 was the warmest (19.11°), but 2017 was only fourth, beaten by 2014 and 2009. The coolest year in this century was 2008 (17.19°), followed by 2001, 2011, and 2012.

Night temperatures

Daily min temp, 19 years

Night temperatures are shown by the mean minimum temperature in the thermometer screen. The year 2018 , at 11.09°, had only the fourth warmest nights. The warmest were in 2014, at 11.34°, followed by 2010 and 2009. Years with nights cooler than 10° on average were 2012, 2008, 2006 and 2001.

Subsoil temperatures

Subsoil temp, 19 years

Yearly temperatures in the subsoil (at 750 mm depth) hardly related at all to air temperatures. 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°). The highest subsoil temperature (22.19°) came in 2013, when the air was not very warm. In 2018, the year with the warmest air, the subsoil temperature was near normal. This record shows the mean subsoil temperature of 20.2° to be 2.3° higher than the mean air temperature of 17.9°.


Rainfall, 19 years

In these years, the average rainfall is close to the long-term mean of 652 mm. The wettest year included here was 2011 which, with 839 mm, was not very wet. However, 2018, with only 327 mm (estimated), was the second driest on record, beaten only by 1946 with 321 mm.


Cloudy mornings %, 19 years

This measure of cloudiness is based on morning observations of the amount of cloud in octas (“eighths”). It is the percent of mornings with more than four octas. The pattern is like that of rainfall, but there was little cloud until 2007, and still quite a lot in 2018.

Daily Temperature Range

Daily temp range, 19 years

The daily temperature range relates closely to other measures of moisture: moisture reduces the range. The two years with least rainfall, 2002 and 2018, had the highest (16.62°) and third-highest daily temperature ranges. Years with high rainfall had low daily temperature ranges (down to 13.40° in 2010).

Dew Point

Morning dew point, 19 years

Early morning dew point is a measure of humidity. The year 2010, with equal highest mean dew point (9.30°), had the most cloud, the narrowest temperature range, and a high rainfall. The year with the lowest dew point, 2013 (5.43°), had a wide temperature range and rainfall below average.. However, the dew point, as estimated, fell during the 19 years, perhaps due to instrument error.

[This graph is wrongly labelled “Daily Min. Dew Point”. It should be “Early Morning Dew Point”. Dew point was estimated at the time of minimum temperature, which is typically a dew point maximum, not minimum.]

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s