Winter 2015 like winter 2014

A low-level lenticular cloud

Low Level Lennie

Weather log for winter 2014There was one short spell of rather cold days in mid-July this year, and another at the very end of August.
Otherwise, this winter was very like the winter before. In mid-June and late August there were humid spells with heavy rain and very warm nights. By contrast, early August had cold nights with very low humidity and no rain. In both years, July had very light falls of rain.
The number of frosts in each season (38; 42) was near normal (44), but in this winter the coldest night (minus 2.1°) was the warmest so far this century.

Weather log for winter 2015

Like last winter, the average night temperature and the cloudiness were a little high, and the dew point very low. Average day temperature was half a degree low, making the daily temperature range narrow.
The winter rainfall, 133 mm, was just above the average (125 mm) and in the 62nd percentile.

Climate for winter 2015


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

Manilla’s Frosts to 2014

Graphical log of frosts

This post updates a similar one by including three more years to make a total of sixteen.

The Number of Frosts in Each Year

The first graph is a log of the number of frosts in each year. The pattern is different when counting all frosts or only severe frosts.
The log for all frosts had two periods of stable, medium numbers of frosts: from 1999 to 2003, and from 2008 to 2011. Three years had many frosts: 2004 (68), 2006 (70), and 2012 (69). The year 2007 had the fewest frosts (43) until beaten by 2013 (34).
In the logs for severe frosts below minus 2° or minus 4° in the thermometer screen, the drought year 2002 stands out as the most frosty by far. It had the coldest mornings: -5.1° on both the 2nd and 11th of July.

The Last Three Years

Monthly frosts in 2012, 2013, and 2014.

The second graph compares the mean seasonal pattern of frosts with the patterns for the three latest years: 2012, 2013, and 2014.
The frost season of 2012, which almost matched the record 70 frosts of 2006, began early and ended late. May had 13 frosts (like the 14 of 2006) and September had 10 (like the 8 of 2003).
The curve for the season of 2013 ( the new record fewest) was like that of a normal frost season, but lower.
The year 2014 was not very frosty, because the season began late, with no frosts in May and only nine in June.

Monthly frosts each year

Graphs showing the seasonal frost patterns for earlier years are copied here.

 

 

 

 

 

 


There is 2013 reserch on frost in NSW titled “Understanding frost risk in a variable and changing climate” reported here.
It is in GRDC Update Papers (Grains Research and development Corporation). The research is done by Steven Crimp and co-workers at CSIRO Climate Adaption Flagship.
Referring to the period 1960 to 2010,
“Over many parts of NSW the frost season length has broadened by as much as 40 days and the mean number of consecutive frost days has increased to 5 days.”

Winter 2014 normal

Berries on a melia tree

Chinaberries in winter

This winter, there were no very warm or very cold spells. There was one sunny spell with a wide daily temperature range in early August, followed by a week with a narrow temperature range.
There were 38 frosts. While this is below the 16-year winter average of 44, it is near the average for the last seven winters. From 2001 to 2006 the winter average was higher: 47 frosts.
Rain fell on 15 days (normal), with a highest reading of 26.6 mm, which is also normal in winter.Weather log for winter 2014

Seasonal means and totals were all not far from normal except for the dew point. The dew point of 0.7 degrees was more than two degrees low, showing extremely dry air, as in winter 2012. The daily minimum temperature was almost a degree high, reducing the temperature range and raising the mean temperature as well.

The winter rainfall total of 106 mm is just below the average (125 mm) and in the 40th percentile.

Climate for winter 2014


Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Temperature, including subsoil at 750 mm, and other data are from 3 Monash Street, Manilla.

Winter 2013 Warm

Weather log winter 2013

This winter, June was very cloudy and wet, July was very warm, and August was warm and dry. This pattern was common across northern NSW.
There were only 29 frosts, well below the winter average of 44, and fewer than in winter 2010 (32).
All winter average temperatures were above normal: daily max (18.9°), up by 0.8°; daily mean (11.6°), up by 1.2°; daily min (4.3°), up by 1.6°. In each case, winter of 2009 had been slightly warmer. As in last winter, the subsoil temperature was very high: 17.0°, which is 2.7 °above normal for winter in the decade from 1999. In that same decade, only 34% of winter mornings were cloudy; this winter’s value of 43% has become normal since.
The winter rainfall total of 134 mm is just above the average (125 mm) and in the 62nd percentile.Climate Winter 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.

Winter 2012: very dry air

Weather log winter 2012

There were two spells of cloudy very wet weather with warm nights, one in the first week of June and one in the second week of July. By contrast, the first week of August was sunny, but with cool days and very cold nights.

Early valley fogs were common in June and July. The total number of frosts (45) was normal, as was the number of severe frosts below minus two degrees (8).
Like last winter, this winter had normal air temperature. Unlike last winter, rainfall was not low, nor the skies extremely cloudy.
Humidity, however, was even lower, marked by a mean early-morning Dew Point of 0.7° (2.2° lower than normal), a new winter record for dry air.
Subsoil temperature was a new winter record high value: 17.1°.
There were 16 rain days, which is just below normal. The winter total of 148.2 mm is in the 66th percentile.Climate winter 2012

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.