Tag Archives: May

May 2011 cloudy, rainy, but not humid

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log May 2011.

May had five rain days (usually only three) but they came very late. The highest rainfall reading, 19.6 mm on the 23rd, ended a 35-day dry spell. Before the rain, the air had become extremely dry. The morning Dew Point on the 17th was -9.3° and the daily minimum temperature on the 15th -2.8°: both were 13-year record low values for May. The daily temperature range reached 24.9° on the 18th.
With the rain came cloudy, cold days. The 30th, with a maximum of only 11.1°, was the coldest May day in this record. It was nearly two degrees below the previous coldest: 12.9° on 29/5/00.

 Comparing May monthsClimate May 2011.

Mean temperatures were a little below average. There were 11 frosts, compared with the usual six.
After sunny April, May was back to the extreme cloudiness of the last three years. The air was not humid at all, however. The mean Dew Point was only slightly higher than in the droughty May of 2006.
The rainfall of 43.2 mm is on the 64th percentile for May, and just above the long-term May average (39.3 mm). May rainfalls have been low (or very low) for a number of years: this was the wettest May since 1998 (74 mm). Rainfall totals for groups of months (up to 360 months) continue to be near normal.

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.

 

Damp end to cloudy May 2010

Posted in Manilla NSW, Monthly weather by

The daily weather logWeather log May 2010

Dry weather with warm days and cool nights lasted most of the month. On the 13th the early morning Dew Point of -6.3° set a record for low humidity in May. The seven-day average temperature was quite low in the second week. Nine mild frosts (usually 6) all came about this time. By the 25th there had been only 57 mm of rain in 14 weeks: an average of barely 4 mm per week. A serious rainfall shortage was developing, despite months of cloudy weather.
Late in the month nights became very humid and warm. Mornings had fog on the 18th and 22nd and mist (visibility one kilometre) on the 27th and 31st. Three days had more than 5 mm of rain. In all, the month had 8 rain days, totalling 28.0 mm.

 Comparing May monthsClimate May 2010

This was the cloudiest May in the 11-year record. The mean maximum temperature and the mean average were normal. The mean minimum was up, reducing the daily temperature range, and the mean Dew Point was down.
The rainfall of 28.0 mm is near the median for May (51st percentile). It is below the long-term average of 40 mm, but no May total has beaten the average since 1998! Rainfall totals for groups of months show just one serious shortage. The 15-month total (538 mm) is now down to the 7th percentile.

Subsoil Temperature

Both graphs now include subsoil temperature measured at 750 mm depth. There the temperature barely changes during a day. It changes slowly with the seasons. Usually it ranges from 26° in February to 14° in July.
As observed in Manilla, the  subsoil temperature does not relate to the normal average temperature of the air in a simple way. In May, it stays about five degrees warmer; in other autumn and winter months it is less than five degrees warmer. In spring and summer it is almost the same as the normal average air temperature.
In autumn 2007 the subsoil temperature was nearly two degrees warmer than usual; in autumn 2008 it was one degree cooler than usual. This is a puzzle, because the average air temperature did not change so much.

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.

 

May 2009 rain by-passed Manilla

Posted in Manilla NSW, Monthly weather by

The daily weather log

Weather log May 2009

More than half the month passed with sunny days, and cool nights (3°) that kept the average temperature down. The 18th was the 34th day without 5 mm of rain.
A lot of rain then came into the region carried on easterly winds from the very warm sea. The coast had five days of heavy rain, causing severe flooding. Manilla had only three rain days, totalling less than 16 mm. At the same time, areas near Mungindi had twice as much. Instead of rain, Manilla got a week of humid overcast days and very warm nights (11°). Thick fog on the 29th did not lift until after 10 am.

 Comparing May months

Climate May 2009

This month had normal temperatures, but it was cloudier than any May since 2001. There were seven mild frosts (normally six), but none was below zero in the screen.

(May 2007 was warm and humid; May 2006 was cool and remarkably sunny.)
The rainfall total (19.0 mm) was in the 34th percentile for the month. While this is below the May median (27 mm), it is well above the most common May reading (5 mm). The two-month total for April and May (73 mm) is on the 33rd percentile. The three-month total (81 mm) is worse: it is on the 14th percentile, but that is not a serious shortage. The four and five month rainfall totals have now fallen to 38th and 41st percentiles. Beyond that, totals are above the median for all periods up to 72 months, except for the 15-month total, which has now fallen to the 45th percentile.

Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperature and other data are from 3 Monash Street, Manilla.

 

Perfect May weather in 2008

Posted in Manilla NSW, Monthly weather by

The daily weather log

Weather log May 2008

The mean daily temperature rose to a normal value by the middle of the month and then tracked down along the usual curve. Daily maxima were near normal except for one cool Sunday. Daily minima were also normal, except for a warm night (12°) on the 16th and six mild frosts.
The second week had very dry air, but the third week was humid, with four days of rain showers totalling 14 mm. A  number of cloudy days produced no rain.

 Comparing May months

Climate May 2008

The weather for May was normal in all respects: maximum, mean, and minimum temperatures, humidity, cloudiness, and rain. Some of us would call it perfect weather!
Normal temperatures break a five-month spell of unusually cool weather. On the other hand, as the graph shows, this month is much cooler than May last year. Six frosts is the normal number for May, and compares with 3 last year and 14 the year before.
Humidity, indicated by early morning Dew Point, is similar to that in 2004 and 2005. It had been higher early in the decade, due to moisture from “La Niña”.
At 14 mm, this May’s rainfall is not very low. Being well below the May average (40 mm) does not mean much. In Manilla, rainfalls in the months of March, April and May are highly “skewed” so that the very lowest rainfalls are the most common. Rainfalls of 5 mm or less occur often – more often than one May month in eight (There are two on the graph!). Fourteen millimetres is in the 25th percentile of May rainfalls.
The rainfall total for this April and May together (34 mm) is in the 9th percentile of two-monthly totals (a serious shortage) and the three-monthly total (36 mm) is in the 2nd percentile (a severe (almost extreme) shortage). The four-month total is better (in the 28th percentile) and the five-month total better still (in the 35th percentile). The six-month total (summer plus autumn) is high: in the 61st percentile. Beyond that, the totals for 9, 12 and more months are all normal, that is, near the median.

Data. Rainfall data is from Manilla Post Office, courtesy of Phil Pinch. Dew point values before August 2005 are from Tamworth Airport 6 am data supplied by the Bureau of Meteorology. Temperature and other data are from 3 Monash Street, Manilla.