Summer 2016-17 the hottest

Young bearded dragon

Tiny Dragon

This summer, like summer 2013-14, was marked by repeated heat waves. The first, early in December, was brief. Another, in mid-January, led into one that was hotter, and persisted through the first half of February. On a weekly basis, temperatures did not fall below normal at any time in the season. Mid-February had the two hottest days of the new century, at 44.9° and 43.8°.
Although there were as many rain days as usual (22), only two days had rainfall exceeding 15 mm, and there was almost no rain in February.

Graphical log for summer 2016-17.

Comparing summer seasons

Mean temperatures set new records for the summer season: daily maximum 35.6°, average 27.6°, and daily minimum 19.7°. Each of these was more than a degree higher than the old record. Nearly all such figures for the months December, January, and February had also been records. However, the subsoil temperature for the summer (24.7°) was low.
Two indicators of moisture were a little low: mean early morning dew point (13.4°) was down 0.7°, and mean daily temperature range (15.9°) was 0.8° wider than usual.
The percentage of cloudy mornings (38%) was almost the same as in the last four summers, and lower than in the previous two. However, 38% is much more cloudy than the “normal” figure of 31% cloudy mornings that was set in the decade 1999-2008. Summers were more sunny then.
This summer’s rainfall was very low. The unofficial total of 101.4 mm would place it as the seventh driest on record. As shown on the graph, summer 2013-14 was drier (85 mm). Otherwise,  there has not been a drier summer in the half-century since 1964-65 (70 mm).

Climate for summer 2016-17


Data. Rainfall figures are usually from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. However, the gauge ceased recording five months ago (8/10/16), and this month’s readings are from my non-standard gauge. All data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

February 2017 had the hottest day

February 2017 was a month of extreme heat and hardly any rain.

Rainbow

No-rain Rainbow

The temperature rose to 44.9° on the 11th, the highest reading in this record from 1999. The next day, at 43.8°, was the next highest, beating readings of 43.7° on 3/01/2014 and 43.2° on 12/01/2013. These extremely hot days were part of a long heat-wave. Every day reached above 30° for 64 days up to the 19th, and the average weekly temperature was above 30° (4° above normal) from the 1st to the 15th.
Nights also remained warmer than normal until, abruptly, the temperature fell to 9.5° on the 20th: the 4th coldest February night! After that, day and night temperatures were normal.
Rain showers were seen frequently, but the only daily readings (unofficial) were 1.1 mm on the 20th and 3.0 mm on the 27th.

Weather log February 2017

Comparing February months

This was by far the hottest February of the new century, with highest values of all three temperatures: mean maximum temperature (36.8°), mean average temperature (28.4°) and mean minimum temperature (20.0°). Subsoil temperature was normal.
While cloudiness was normal, a rather low dew point and rather wide daily temperature range reflect low moisture, while the rainfall was very low indeed.
The estimated monthly rainfall total of 4.1 mm exceeds that of just a very few February months: 1901 (2 mm), 1932 (3 mm), and perhaps 1923 and 1938 (both 4 mm), but no others. However, this extremely low rainfall for the month has not brought any serious rainfall shortages for totals of more than one month. The four-month total of 123 mm is at the 17th percentile, which is not even as bad as the five-year total (2844 mm) which is at the 14th percentile.

Climate for February 2017.


Data. Rainfall figures are usually from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. However, the gauge ceased recording four months ago (8/10/16), and this month’s readings are from my non-standard gauge. All data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

January 2017 had the hottest night

Cumulus congestus at 130 km

Showers at 130 kilometres

The daily weather log

In the early morning on the 14th, the minimum temperature was 28.2°, the hottest night in this record from 1999. That beat 27.8° set on November the 28th, 2009. Of January months, only this month and January 2006 had no nights as cool as 15°. There were no cool days either: like January 2002, no days were as cool as 30° (and none since 16/12/16). However, only two days this month went over 40°: the 12th with 41.4° and the 13th with 41.2°. That hardly compares with January 2003, which had five. The weekly average temperature was over 30° (4.7° above normal) from the 11th to the 15th. Late in the month, it got as low as 28°, then climbed again.
Showers and storms brought rain on 8 days, but the maximum was only 19.8 mm.

Weather log January 2017

Comparing January months

As in December, this was the hottest January of the new century. It easily beat January 2013 in mean daily maximum (36.4°), mean average (28.7°), and especially mean daily minimum (hot nights: 21.0°). As this months days and nights were both so warm, the daily temperature range was quite normal (15.4°).
Contradicting the high air temperatures, the subsoil temperature was below normal, at 25.1°.
The month was more humid than usual. Afternoon humidity, at 36%, was the highest January value in twelve years (normally 28%), and early morning dew point was the highest in eleven years.
The monthly rainfall total of 48.5 mm is in the 30th percentile, well below the average of 87 mm. Rainfall totals for more than one month still show no shortages. The 48-month total of 2320 mm (down 280 mm) has the lowest percentile value (23rd percentile) as a legacy of dry months around 2013.

Climate for January

 


Data. Rainfall figures are usually from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. However, the gauge ceased recording four months ago (8/10/16), and this month’s readings are from my non-standard gauge. All data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

December 2016 was hot

A bearded dragon camouflaged on a bush

Hidden Dragon

Hot weather in this month came in the first and last weeks which, on average, were 4.8° and 3.6° warmer than normal. On the 5th, both day and night were nine degrees above normal. There was just one 40° day, on the 30th. In December months from 1999, there have now been five with one 40° day, but none with more than one. The two hottest, at 40.6°, came in 2005 and 2012.
Rain fell frequently (on 12 days), but it was light (max: 17.8 mm). Plants dried out.
Throughout the month, tiny “flies” swarmed in millions. They are native Rutherglen Bugs (Nysius vinitor), a sap-sucking pest of crops such as sunflower.

 Weather log December 2016

Comparing December months

This was the hottest December of the new century. December 2009 had been the hottest, but this month had a higher mean daily maximum (33.8° vs. 33.1°) and a slightly higher average (26.0° vs. 25.9°). December 2009 still had the warmest nights: the daily minimum was 18.6° then versus 18.2° now. As this month’s days and nights were both so warm, the daily temperature range was quite normal (15.6°).
Contradicting the high air temperatures, the subsoil temperature was well below the normal value of 24.3°. At 22.7°, it was the coolest December value since 1999, when it had been 22.5°.
The month was rather cloudy, which does not match well with the rather low dew point and rainfall. The monthly rainfall total of 48.8 mm is in the 34th percentile, well below the average of 74 mm.

Climate fro December 2016

The Year 2016

As in 2015, the average temperatures for the year 2016 were close to normal by day, and half a degree above normal by night. The subsoil temperature, which had been normal in 2015, fell to half a degree low. Air temperatures had been warmer in 2014 and 2009, and cooler in 2008.
Rainfall, at 775 mm, was in the 76th percentile, well above the 125-year average of 652 mm. The mid-year months of June, August, and September were very wet, while November as well as February, March and April were dry. High rainfall is rare in mid-year months, but 1998 had a similar pattern.
Temperatures also were far from normal in some months. They were about 2° higher than normal through the autumn and 2° lower than normal through the spring.


Data. Rainfall figures are usually from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. However, the gauge ceased recording on the 8th of October, and later readings are from my non-standard gauge. All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

Cool spring 2016

Photo of a wildflower

Nodding Chocolate Lilies

Through September, days were very cool, making for a narrow daily temperature range. Then, through October, both days and nights were very cool. In November, days and nights were nearer to normal but, in contrast to September, the daily temperature range was wide. The dew point failed to rise during the season, making the air very dry in November.
Rain fell frequently up to the middle of November, then ceased. There were 24 rain days, when there are normally 19 in spring. The highest reading was 28.8 mm on the 14th of September. The season total of 216.4 mm was rather high, in the 77th percentile.

Graphical log for spring 2016
All temperature measures were below normal by 1.5° to 2.0°. Only spring of 2001 had low values like that but in 2010 the mean daily maximum (only) was 2.5° below normal.
Measures of moisture were near normal, with cloud, rainfall, and daily temperature range on the moist side, and dew point on the dry side.

Climate for spring 2016


Data. Rainfall figures for this season began from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. That gauge ceased reporting on the 8th of October, and later readings are from my non-standard gauge. All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

November 2016 was arid

While there was some rain, measures of moisture this month were at or near their lowest November values for this century.

Photo of a yellow dragon lizard

Eastern Bearded Dragon

There were five rain days early in the month, the highest reading being 15.0 mm on the 10th. Some early days were overcast, but skies were sunny after the 15th.
Temperatures rose and fell, but few days or nights were especially hot or cold. The early morning of the 6th went as low as 5.4° , which is 7.8° below normal. Curiously, the month had a record number of cool nights: 12 nights were cooler than 10°, when there are usually only about 5.
Weekly average temperatures, which had been very low in October, were nearer to normal through this month.

Weather log November 2016

Comparing November months

Both the mean maximum temperature (30.2°) and the mean average temperature (20.9°) were near normal, but the mean minimum temperature (11.7°) was very low. On this record, only 1999 had colder November nights (at 11.6°!). This extreme value brought a very wide mean daily temperature range of 18.5°, also a record.
The subsoil was at its coolest recorded November value: 19.5°.
A very wide daily temperature range is one of the measures of moisture showing this month to be arid. The early morning dew point of 5.6° was the lowest November value on this record, and the cloudiness (30%) was low. The monthly rainfall total of 21.9 mm, while not really low (22nd percentile), was the lowest November total in the 26 years since 1990, which had only 15 mm.

Climate for November 2016


Data. Rainfall figures are usually from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. However, the gauge ceased recording on the 8th of October, and later readings are from my non-standard gauge. All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.

October 2016 was cold

Photo of the bark of a Eucalyptus tree

White Box at Sunset

In this month, each of five sunny spells of normal temperature was followed by a cold, cloudy, humid break, generally with rain. Only a few days were warmer than normal, including the 27th. That was the first 30° day of the season, five weeks late.
The average weekly temperature was persistently three or four degrees cooler than normal. One cold week about the 15th was more than five degrees below normal, and the warmest week, about the 29th, was still half a degree low.
Most nights were very cool. I recorded no frosts, but others may have done. My most recent frost was early in September.
There were six rain days, not counting two readings of 0.2 mm. The highest reading was 20.0 mm on the 23rd.

Weather log for October 2016

Comparing October months

This was the coldest October on this record from 1999. That includes not only the maximum, mean, and minimum air temperatures read in the Gill Screen, but also the subsoil temperature at 750 mm. Noting that October 2015 had the highest October temperatures, the sudden collapse is astonishing. Last October was three degrees warmer than normal; this month was almost three degrees colder than normal. Put another way, the seasonal warming is a month late this year and was a month early last year.
Unlike September, there was not an unusual amount of moisture in October. Humidity, cloudiness and daily temperature range were near normal.
The monthly rainfall total of 72.1 mm was above the average of 58 mm, in the 70th percentile.
I have discussed the current drought status (that is, drought-free) in another post.

Climate for October 2016


Data. Rainfall figures are usually from the automatic rain gauge at Manilla, published on the internet by the Bureau of Meteorology as Station 55031. However, the gauge ceased recording on the 8th of October, and later readings are from my non-standard gauge. All other data, including subsoil at 750 mm, are from 3 Monash Street, Manilla.