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.

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February 2016: hot, dry days

Photo of cooba blossom

Cooba in February

Weekly average temperatures began 2 or 3 degrees low, but ended with a long warm spell 3 degrees high, that extended into March. Days were especially hot, with the 26th reaching 41.5°, the equal second hottest February day. Nights were seldom very warm, and the early morning of the 26th was 25° cooler than the afternoon.
Few days were cloudy, none of them late in the month
Rain fell only on the 3rd, as three heavy showers of 7mm, 27mm and 13mm. The second shower, at 5pm, had the most intense rain of the new century: 27 mm in less than 27 minutes. Bureau of Meteorology data show that such a half-hour storm, yielding 1 mm of rain per minute, has only a 10% chance of happening here in any year. It is a “one in 10 year event”.

Weather log February 2016

Comparing February months

While the average temperature for the month (25.8°) was normal, the mean daily maximum, at 34.7°, was the hottest for February. A rather low mean daily minimum, (16.8°) made the daily temperature range a desert-like 17.9°. This is the widest February value, 3.5° wider than normal.
Other signs of dryness were the low early morning dew point (10.8°) and very few cloudy mornings (17%).
The total rainfall of 47mm was below the average of 67 mm, but right on the median 50th percentile: just half of all February months have been wetter. Again, there are no serious rainfall shortages for totals for any number of months.

Climate for February 2016


Data. All data, including subsoil at 750 mm, are from 3 Monash Street, Manilla. Rainfall data up to 26/3/15 is from Manilla Post Office, Station 055031.

3-year trends to February 2016

Parametric plots of smoothed climate variables at Manilla
“February 2016: suddenly dry”

Trends to February 2016

February raw anomaly data (orange)

In February 2016, raw values for anomalies moved completely across the graphs, from cool and moist in January, generally to hot and dry in February. As in a desert, days became very hot, skies very sunny, and the daily temperature range extreme. Rainfall and dew point were only moderately low, while daily minimum temperature abruptly fell very low, and subsoil temperature remained very low.

 Fully smoothed data (red)

With data for August 2015, fully smoothed data is complete for winter 2015. Most anomalies for the season were quite small, but were moving away from cool and moist.

Trend lines on the graphs

Manilla’s climate often oscillates along the blue trend lines from bottom left (cool, moist) to top right (hot, dry) on the graphs. The climate can also vary along other axes.
In this time-frame the sub-soil temperature anomaly (bottom right graph) is leading the daily maximum temperature anomaly by several months. That produces a clockwise looping pattern. The daily minimum temperature anomaly (bottom left graph) sometimes moves with the daily maximum temperature anomaly, and sometimes moves against it. When against it, as from July 2013 to October 2014, the climate swings between Continental, with hot days and cool nights (as October 2013), and Maritime, with cool days and warm nights (as May 2014). Current raw data for January and February 2016 show a large swing from Maritime to Continental.


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.

Still hot and dry in November 2014

Silky oak trees in full bloom

November Silky Oaks

Although the month began near normal, with two rain days, the weather became hot and dry again. Saturday the 22nd reached 41.4°, to be the second hottest November day on this 15-year record.
There were two heat waves, with the average weekly temperature above normal by 6.1° on the 12th and by 7.0° on Sunday the 23rd. (November of 2009 had a worse heat wave, being above normal by 9.5°, and reaching 31.3°: the hottest week in any month.)
Most nights this month were warm, with low dew points. By contrast, many days were cloudy.

 Weather log November 2014

Comparing November months

On average, the month was not quite as hot as November 2009, the hottest this century. The air was again very dry, with an early morning dew point of 7.1°, a little higher than the lowest value (5.7°) recorded for November last year.
Following only three years after the wettest November on the 130-year record (242.9 mm), the total rainfall of only 24 mm was in the 15th percentile. That is, such low November rainfalls happen about one year in seven. However, the time since a lower November rainfall (15 mm in November 1990) is thirteen years: the longest gap ever.
For the third month in a row, little changed in rainfall totals for periods of more than one month. There is no longer a serious shortage in the 6-month total (now in the 10th percentile) but there are now serious shortages in the totals for 5 months (9th percentile), 9 months (8th percentile), 15 months (6th percentile), 18 months (6th percentile), and 30 months (9th percentile). There is one severe shortage: the total for 12 months (393 mm) is in the 4th percentile.

Climate fro November 2014


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.

October 2014 hot and dry

Blooms of Melia azedarach

Fragrant white cedar blooms

The month began with a warm spell, which was followed by a cool spell about the 15th. It ended with a long hot spell, 4.8 degrees above normal, including the hottest October day this century (38.1°) on the 26th. As usual, there were no frosts.

Of three rain days (usually seven), only the 14th had much rain: 26.4 mm, with heavy showers.
Half the mornings had no cloud at all, and nine days had very wide temperature ranges, greater than 20°.

Weather log October 2014

 Comparing October months

This was the hottest October month at Manilla in this 16-year record. Maximum, mean and minimum temperatures were all highest values, but the maximum was no higher than in October 2007. The subsoil temperature returned to a value below normal.
As indicators of low moisture, the daily temperature range was very high and cloudiness and dew point were very low, as in the last two October months. Even less cloud had been seen in 2002 and 2004.
Recently, lower rainfall occurred in October 2002 (15.0 mm), 2012 (12.6 mm), and 2013 (15.0 mm). However, this month’s total of 27.0 mm is well below the October average of 58 mm, in the 21st percentile. Since last month, little has changed in rainfall totals for periods of more than one month. There is still a serious shortage in the 6-month total (8th percentile) but not now in the 9-month total (10th percentile). The 15-month total has advanced to severe (4th percentile), while the 18-month total has retreated to serious (5th percentile). A serious shortage has also appeared in the 30-month total (8th percentile).

Climate October 2014  


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.

2013-14: Third Driest Summer

Weather log summer 2013-14.

After a cool start, this summer had no more cool weather. There were five warm spells 3° to 4° warmer than normal. Days were particularly warm, with a new 21st century record high of 43.7° set on 3/1/14. During warm spells, nights were also warm, but often 17° cooler than the days. The air was phenomenally dry in early January, with morning dew points (usually 14°) falling below zero three times. There were only 14 rain days (usually 21), and the heaviest fall of 18.8 mm was a 21st century record low for summer.


Taking average values, this summer had the highest daily maximum temperature this century: the value of 34.3° beats the 34.1° of 2005-6. However, the daily mean of 26.1° does not beat the 26.3° of 2005-6. By contrast, the summer of 2011-12 was the coldest, by day and by night. The total rainfall of just 84.8 mm makes this the third driest summer in the 131-year record, after 1929-30 (66 mm) and 1964-5 (70 mm). The summers of 1999-2000 and the two following were also very dry (125 mm, 158 mm, 137 mm) but this summer had not only less rain but also very much drier air and a wider daily range of temperature. Both the low dew point, 8.6° , and the wide daily temperature range, 16.4°, were record values. The earlier dry summers were less cloudy, however.Climate summer 2013-14.

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.

Spring 2013 hot and dry

 

Weather log spring 2013.Through most of this spring season, days were hot and sunny, and the humidity and dew point were very low. This changed for the final three weeks, when two-thirds of the season’s rain fell, and the weather was cool and humid.
Along with 2002 and 2009, this was one of three hot springs this century. However, this spring had cooler nights. The springs of 2002, 2012 and 2013 were the driest, counting humidity and cloud as well as rainfall. This spring had the lowest humidity by far, and last spring the second lowest. Low humidity means crops and animals (and people) need more water.
The total rainfall (130 mm) was in the 36th percentile for springs. Rain fell on only 13 days: more than in spring of 2002 (9 days), but fewer than in 2003 (15) or 2012 (16).Climate spring 2013

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.