Category Archives: Monthly weather

Extremely warm July 2013

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log July 2013.

There were three warm spells and no cold spells in July. Fourteen days went over 20 degrees, instead of the usual four. There were only eleven frosts, the fewest in 15 July months (usually 17). In five rain days, two high rainfall figures came on the 20th (19.2mm) and the 21st (9.6mm).

Comparing July monthsClimate July 2013.

After June’s extreme cloudiness and rain, July was very near to normal in everything but temperature. The average values of daily maximum, daily minimum, and daily mean temperature were all just under two degrees above normal. The daily maximum and daily mean are 15-year record high values, but the daily minimum had been higher in July 2010: 2.4 degrees above normal.
(Note: My “normal” is the ten year average from March 1999. For the official normal period 1961-1990 there are no Manilla figures (except rainfall). This month’s very high temperatures would be (perhaps) just over 2 degrees above the 1961-1990 average.)
Rainfall, at 29.8 mm, is in the 43rd percentile, a bit below the average (41.1mm). Rainfall totals for 24 months and more are very high. This accounts for the rare appearance of water flowing locally in Greenhatch Creek.

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.

June 2013: Extreme Cloud and Rain

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log June 2013.

The first weeks were warmer than usual, including a Queen’s Birthday Saturday that reached a pleasant 23°. In contrast, Tuesday the 25th reached only 9.7° making it the fifth coldest day of the century.

There were hardly any sunny mornings in the month, and most were close to overcast. Cloud kept the nights warm, limiting the number of frosts to only eight. The night of the 7th had a minimum of 12.6°, nine degrees above normal.

The wettest of 10 rain days had 38.0 mm, almost as high as a 38.2 mm reading in June 2008.

Comparing June MonthsClimate June 2013.

Extreme cloudiness and rain lead this month’s climate values. Having 73% of mornings with cloud covering more than half the sky makes this the cloudiest month in the 21st century by far. July 2010 and March 2011 reached only 61%. This month’s figure is over twice the June average of 33% cloudy mornings.

With a rainfall total of 98.0 mm, this is the eighth wettest June in 131 years. The wettest was June 1920, with 173 mm. That was the first of a cluster of four extremely wet Junes, ending with June 1931, that were among the ten wettest. Only eight years ago, June 2005 was the sixth wettest on record, at 109 mm.
This month’s rainfall defers any shortage. Among totals for more than one month, the driest is the 34th percentile for the last three months (Total 3-month rain: “only” 116 mm).
The mean daily maximum temperature, 17.3°, is just 0.5° below normal, but the mean daily minimum, 5.7°, is very high, 2.9° above normal (as in 2005, 2008 and 2009). The subsoil remains very warm.

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.

Another dry May in 2013

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log May 2013

Most days were warm and sunny, but there were cold, cloudy days from the 14th to the 24th, and three of them had a little rain. By the end of the month, there had been only 26.6 mm of rain in 90 days.
There were five frosty mornings, which is normal.

 Comparing May monthsClimate May 2013.

The mean maximum temperature was half a degree high and the mean minimum half a degree low. The mean early morning dew point (2.6°) showed low humidity, but it was not as low as the May record of 0.8° set last year. There were far more cloudy mornings (42%) than usual (24%), but fewer than in 2010 or 2011 (48%). The subsoil was 2.4° warmer than normal: its autumn cooling remained three weeks late.

The rainfall total of 13.6 mm was far below the average of 40.3 mm, but May has less rain than that in 23% of the years. Furthermore, Manilla’s May rainfall has been low for many years: in this century, only May 2011 (43.2 mm) beat the long-term average.
The two month total of 18 mm is now a severe shortage: in the 3rd percentile.

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.

 

April 2013: Very Dry Air

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log April 2013.

For most of the month, days were sunny and fairly warm, while nights were cool (but not frosty). The last days were several degrees warmer than normal: as warm as the first days. Two afternoons had extremely dry air, with relative humidity below 10%. While two days had a little rain, the month ended with no readings above 5 mm in eight weeks.

 Comparing April monthsClimate April 2013

 

The mean maximum temperature was a little high and the mean minimum rather low, making the daily temperature range (18.3°) an April record. The mean early morning dew point (4.3°) was also a record (low) value, but cloudiness was normal. The subsoil was almost 2° warmer than normal: its autumn cooling was about three weeks late.
The rainfall total of 4.8 mm was far below the average of 39.3 mm, but April has less rain than that in 15% of the years.

Five Recent Months had Very Dry Air

I have put headlines about very dry air on five monthly weather reports in the last twelve. It is true: the air has been much drier than it was from 1999 to 2009.
I judge the moisture in the air mainly by the dew point – the temperature when dew would form. Normally the early morning dew point, as a monthly average, changes through the year from 15 degrees in February to 2 degrees in July. In some recent months it has been far lower than what is normal for the month:

  • May 2012: 4.4° below normal;
  • August 2012: 4.4° below normal;
  • September 2012: 4.6° below normal;
  • October 2012: 6.6°(!) below normal;
  • April 2013: 4.7° below normal.

Even in the 2002 drought, the furthest the dew point went below normal was 3.9°, in October.
One degree of change in dew point is like 5% change in relative humidity. In these months the morning relative humidity has been below normal by 20% to 35%. Afternoon humidity has been down by more: many days have gone below 10% humidity. These extremely low humidity values must affect crops and pastures, pests and diseases, and may affect health.

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.

 

Rainy Cool March 2013

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log March 2013.

Days and nights were cooler than normal until late in the month. The first day was the coldest: 22.2°. March began with 31 mm of rain on the 1st, and 45.4 mm on the 2nd, but little fell later.

 Comparing March monthsClimate March 2013.

In most ways, the month was like March last year: a bit cool, particularly in the day-time, but warm in the subsoil, and rather cloudy, but not humid. However, there was much more rain.

The total rainfall (84.6 mm) was in the 80th percentile, far above the mean of 53.3 mm. Rainfall totals for groups of months (2 months up to 360 months) are now all above their median values. The 36-month total of 2328 mm is extremely high, near the 36-month record of 2662 mm set in October 1998.

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.