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.

3-year trends to February 2017

Parametric plots of smoothed climate variables at Manilla
“Extreme heat with little rain”

3-year trends to February 2017.

February raw anomaly data (orange)

In February 2017 days became extremely hot and rainfall very low. The subsoil temperature rose from low to normal.

 Fully smoothed data (red)

Fully-smoothed values are now available for the winter months (June, July, and August) of 2016. That winter, as daily maximum temperature fell through normal values, a maximum in moisture was shown by maxima in rainfall, cloudiness, and dew point, and a minimum in daily temperature range. None of the smoothed values was extreme; in fact, the dew point remained on the dry side of normal.
Not only daily maximum temperature anomaly fell during the summer. Both the daily minimum temperature anomaly and the subsoil temperature anomaly also fell. The smoothed daily minimum temperature anomaly had just reached a record high value in May, and was still above normal as the summer ended.


Note:

Fully smoothed data – Gaussian smoothing with half-width 6 months – are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange. January data points are marked by squares.
Blue diamonds and the dashed blue rectangle show the extreme values in the fully smoothed data record since September 1999.

Normal values are based on averages for the decade from March 1999.* They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 * Normal values for rainfall are based on averages for the 125 years beginning 1883.

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.

3-year trends to January 2017

Parametric plots of smoothed climate variables at Manilla
“January 2017 very hot”

3-year trends to January 2017

January raw anomaly data (orange)

In January 2017 both days and nights became even hotter. While rainfall was low, dew point was high.

 Fully smoothed data (red)

At the time of the latest fully-smoothed anomalies, in July 2016, most variables were still moving towards towards cool and moist.


Note:

Fully smoothed data – Gaussian smoothing with half-width 6 months – are plotted in red, partly smoothed data uncoloured, and raw data for the last data point in orange. January data points are marked by squares.
Blue diamonds and the dashed blue rectangle show the extreme values in the fully smoothed data record since September 1999.

Normal values are based on averages for the decade from March 1999.* They appear on these graphs as a turquoise (turquoise) circle at the origin (0,0). A range of anomalies called “normal” is shown by a dashed rectangle in aqua (aqua). For values in degrees, the assigned normal range is +/-0.7°; for cloudiness, +/-7%; for monthly rainfall, +/-14 mm.

 * Normal values for rainfall are based on averages for the 125 years beginning 1883.

Seasons were strange in 2016

In the year 2016, the seasonal climate cycles at Manilla, NSW were abnormal. Heat and cold, moisture and dryness did not come at the usual times.

Temperature and rainfall graphs

Mean monthly temperature

 

Graphs of monthly temperatures, normal and 2016The first graph shows the mean temperatures for each calendar month, both in a normal year (red) and in the year 2016 (blue). In 2016. earlier months, such as April, were warmer, and later months, such as October, were cooler. The difference (anomaly) is plotted below. Anomaly values in this year rise and fall rather steadily in a single cycle that lags months behind the normal summer-winter cycle. The amplitude of this anomaly cycle in 2016 is 5.3 degrees, which is nearly one third of the normal summer to winter amplitude of 16.4 degrees.

 

Monthly total rainfall

Graphs of monthly rainfall totals, normal and 2016In the same format, the second graph shows the rainfall totals for each calendar month, both in a normal year (red) and in the year 2016 (blue). The mid-year months of June, August, and September, usually dry, were very wet in 2016. The anomaly graph adds to this that rainfall was very low in February, March and April, and again in November and December. Rainfall anomaly does not show such a clear cycle as temperature does, but the effect is bigger. The difference in anomaly between September (+80 mm) and November (-40 mm) is 120 mm, while normally the difference between the wettest month (January) and the driest month (April) is only 48 mm.

Climate anomaly graphs and trends for 2016

The other two graphs add more climate anomaly variables and show the trends through the year 2016.
[See Notes below for an explanation.]

Monthly heat anomalies for 2016

Heat anomalies and trends

Continue reading

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.