2019-20 summer hot and moist

Sef-sown senna plants

Pepper-leaf Senna

Through December and January, this summer had a series of heat waves perhaps worse than those of the previous two summers, and rainfall and humidity were low. Similar droughty weather elsewhere brought catastrophic bushfires.
On the 3rd of February the weather changed dramatically. Heat waves were replaced by spells of cool or normal temperature, with high humidity, overcast days, and rain. Up to that date, cool spells had not occurred since November 2018, 15 months earlier. During those 15 months, regardless of the season, the weekly mean temperature often rose several degrees above normal, but never fell below normal.
Coincidentally, there were 14 rain days in both the hot-dry part of the season (65 days) and in the cool-wet part (26 days).

Weather log summer 2019-20

Seasonal average or total figures for this summer mean little because of the climatic break from 3 February.
Mean temperatures (max, mean, min) were close to the records set in the summers of 2017 and 2019, which they would have exceeded if February had not become cooler. Subsoil temperature remained normal.
In summer 2018-19, two of the moisture measures (daily temperature range and cloudiness) had been near normal, while rainfall and dew point had been low. Now, in 2019-20, rainfall and dew point were higher, making all four moisture measures normal.
The summer rainfall total of 232 mm is at the 55th percentile, very close to the average (227 mm).

Manilla summer climate


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. I have used it since 20 July, when the Museum gauge began recording again.  Unfortunately, the gauge failed during this season (25/02/2020 ). Pending repair, I am using my own gauge. My estimates of early morning dew point have become anomalously low. From 1 August 2019, I use values taken from Tamworth Airport graphs at the time of minimum temperature.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Spring 2019 hot and very dry

Blooming senna bush

Senna coronilloides

Spring was marked by a succession of warm and cool spells. Nights varied around the normal seasonal temperature but days had no spells cooler than normal. A hot spell late in November had days 6° above normal as a weekly average. The dew point showed very dry air in mid-November.
There were nine rain days, as in the droughty spring of 2002. The highest reading was 16.6 mm. Rainy and cloudy days came about every three weeks.

Weather log spring 2019

The hot dry climate this spring was very like that of 2014, and quite unlike the cool wet climate of 2016.
Days, averaging 29.0°, were hotter than in any spring except 2002 (29.2°). Nights, at 11.2°, were only half a degree above average. (The winter of 2019 had a similar pattern.)
Dryness was shown by very little morning cloud (21%), very low early-morning dew point (3.7°) and very wide daily temperature range (17.8°).
The total rainfall of 62.4 mm makes this the fourth driest spring, after 1957 (23 mm), 1944 (40 mm), and 1951 (54 mm).

Climate spring 2019


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. I have used it since 20 July, when the Museum gauge began recording again. My estimates of early morning dew point have become anomalously low. From 1 August 2019, I use values taken from Tamworth Airport graphs at the time of minimum temperature.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Winter 2019 lowest rainfall?

White box eucalyptus tree

White Box Tree

There were several warm spells, mainly as warm days. The warmest was in early July, when days were 4.2° high and nights 4.0°. The only unusual daily temperatures were one high maximum of 27.1° and one low maximum of 11.3° in July.

There were 41 frosts, normally 44.
As in the drought year of 2002, there were only 8 rain days. The highest reading (estimated) was only 5.5 mm on 9 July.

Weather log winter 2019

This winter had the warmest days of the new century (19.5°) but nights that were near normal (3.2°).
Apart from the extremely low rainfall, the other moisture indicators (little cloud, low dew point, wide daily temperature range) were not as severe as in winter 2018.
The total rainfall of 20.9 mm is the 2nd lowest on record for winter. However, it may actually be the lowest. Although the year 1888 had recorded winter rainfall of only 6 mm, there is doubt about that. Daily readings are missing for June and July. The next lowest was 1946, with 29 mm, then 1972 and 1982, both with 32 mm.

winter climate 2019


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. In this season, I used my own readings until 20 July, when the Museum gauge began recording again. My estimates of early morning dew point have become anomalously low. From 1 August 2019, I use values taken from Tamworth Airport graphs at the time of minimum temperature.
All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Another warm autumn, 2019

Lake Keepit very low

Keepit Dam at 0.9%

This season had a series of warm spells separated by normal autumn temperatures. The warmest, about 4° above normal, came in early March, late April and late May. Dry air came at cooler times, near the 1st of March and the 12th of April. Most of the rain came in two very wet days: the 30th of March and the 4th of May (61 mm).

Weather log autumn 2019

Comparing autumn seasons

As in 2018 and 2016, autumn was very warm. Although autumn 2016 had the highest mean temperature of the new century, this autumn had the warmest nights: 12.7°.
Despite the on-going drought, measures of moisture were near normal for the season. Cloudy days reached 37%, the daily temperature range (14.3°) was quite narrow, and the early morning dew point (7.2°) not low. The rainfall total, 117 mm (est.), was at the median value, not far below the mean of 134 mm.

Manilla clmate for autumn


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. Station 55312 recorded no readings this autumn. I used my own readings for the whole season.

All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

2018-19 summer 2nd driest

Cumulonimbus and towering cumulus

Storm at Dusk

This summer had 7 very hot days above 40°, and 11 very hot nights above 24°.
The worst heat waves came in January. Around the 17th, weekly temperatures were more than 6° above normal, with days at about 41°, and nights 24°. Near the 28th, nights were even warmer. Episodes of very low dew point came at times of lower temperature.
Thirteen rain days were scattered through the season, the highest readings being 25.0 mm on 16 December and 18.0 mm on 21 January.

Weather log summer 2018-19

Comparing summer seasons

Average temperatures were almost the same as in the hot summer of 2016-17. Days, at 35.5°, were slightly cooler and nights, at 20.1°, slightly warmer. The resulting average, 27.8°, was a new record summer temperature, beating 2016-17 by 0.2°.
Remarkably, the mean subsoil temperature, 25.5°, was not high, but normal.
Similarly, daily temperature range (15.4°) and cloudiness (22%) were normal. (Recent summers have been cloudy.) Dryness was shown only by very low humidity and rainfall.
The mean early morning dew point for this summer (10.4°) was second lowest in the 19-year record. Only that of summer 2013-14 (8.6°) was lower.
The total rainfall for the summer, 70 mm, was equal second driest with 1965, the driest summer being 1930, which had 66 mm.

Climate for summer 2018-19


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. Station 55312 recorded no readings this summer. I used my own readings for the whole season.

All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Spring 2018 warm

Native vine blossoms

Wonga wonga in spring

This spring was marked by very high temperature in the first week of November. Both days and nights were about five degrees above normal, as hot as expected in mid-summer. Less extreme warmth also occurred in the second half of October and in the second week of September. Periods of very dry air (marked “ARID”) came in mid-September, late November, and at the time of very high temperature.
There were 23 rain days (normally 19), but there was one rainless period of 17 days in September. No day had more than 17 mm of rain.

Weather log spring 2018

The season’s rainfall of 114 mm was at the 24th percentile, about 50 mm below average (166 mm). [The highest rainfall on this graph, spring 2016, is only 45 mm above average.] Other measures of moisture this spring (cloud, dew point, and low daily temperature range) were similar to those of spring 2017 and 2016. They were much moister than those of spring 2013.
The season was warm, with days 0.5° above average and nights 1.5° above average. Spring 2016 had been three degrees cooler. The subsoil temperature was below normal, as it was in the three previous spring seasons.

Climate for spring 2018


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. Station 55312 recorded no readings in spring 2018. I used my own readings for the whole season.

All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Winter 2018 had the driest air

A gum-tree blowing in the wind

Wind-blown Gum-tree

Temperatures varied widely, especially at night. In both mid-July and mid-August, the weekly mean night temperatures were more than 4° low. At these times, the air was extremely dry.
Early in July night temperatures were nearly 4° high, while late in July it was the day temperatures that were more than 4° high. The daily temperature range was almost 21° in mid-July, having been less than 13° in mid-June.
There were 16 rain days, but the highest reading (estimated) was only 10.2 mm.

Weather log for winter 2018

Last winter’s report had been headlined: “Dry air in winter 2017”. This winter was even drier by all measures. In particular, the mean early morning dew point set a new record of -3.0°. The best match in this century is the winter of 2002. Both had warm days, cold nights, wide daily temperature range, little cloud and low dew point.
The total rainfall of 42 mm makes this the 9th driest winter on record, displacing winter 2002, which had 44 mm. (The year 1888 had the lowest winter rainfall total: 6 mm. However, daily readings are missing. The next lowest was 1946, with 29 mm, then 1972 and 1982, both with 32 mm.)

Climate for winter 2018


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. During this winter season 20 daily readings were missed, including several days with significant falls of rain. I have used my own readings for the whole season.

All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.