Damp end to cloudy May 2010

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.

 

April 2010 rather warm and dry

The daily weather logWeather log April 2010

Although the month began with normal temperatures and some rain, the third week became warm, and gardens dried out. On the 26th 9.6 mm of rain was recorded, bringing the monthly total to 22.2 mm in four rain days (the usual number). The month ended sunny with nights that were cooler, but far from frosty.

 Comparing April monthsClimate April 2010

This April was rather warm and dry, but not nearly as warm and dry as April 2005. That month was three degrees warmer than normal and had only 1.6 mm of rain! It had just one cloudy morning, compared to thirteen this month.

The rainfall of 22.2 mm is in the 36th percentile for April, below the long-term average of 38 mm. Rainfall totals for groups of months have fallen, but there are still no serious shortages.. The 12-month total (448 mm) is now down to the 11th percentile: just above the “serious” level.


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

 

Late March 2010 Warmth

The daily weather logWeather log March 2010

After three early rain days, there was a long spell of warm sunny weather. From the middle of the month, all temperatures rose well above normal. The maximum on the 20th went to 35.7° and the minimum on the 28th to 20.6°. A rain-band in the district in the last days yielded only 8 mm, bringing the month’s total to 31.8 mm in four rain days.

 Comparing March monthsClimate March 2010

While the average maximum and Dew Point readings were near normal, the mean and minimum readings were very high. There were more cloudy mornings than any March in the 11-year record, and the daily temperature range (14.1°) was narrow – not much wider than the 13.5° recorded in March 2007. This month was very like that one, but the rain then was four times as heavy.
The rainfall of 31.8 mm is in the 43rd percentile for March, below the long-term average of 51 mm. There are no serious shortages in rainfalls for groups of months. The worst are the 12-month total of 480 mm (16th percentile) and the nine-year total of 5388mm (12th percentile), which is just under 600 mm/year. (The 125-year average is 652 mm/year, and the median (50th percentile) is 627 mm/year.)


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

 

Warm Nights in Summer 2009-10

 

Weather log summer 2009-10

No warm spell this summer matched that of late November, which had four days over 40°. There was only one 40° day all summer. By February there were no warm spells.
Summer began hot and very dry, with clear skies and low humidity. Year’s end saw days of rain, low cloud and extremely high humidity. In mid-January the air was again very dry, but cool.


The mean daily maximum temperature was normal, but the mean minimum (18.7°) was the highest in eleven summers. The number of nights warmer than 20° (34) is also the highest, nearly twice the usual number.
The total rainfall of 190 mm is below the long-term summer average of 225 mm. It is in the 42nd percentile.
At 42% cloudy mornings, this summer was very cloudy, but not extremely cloudy like the summer of 2007-08 (53%). These summers shared the record for completely overcast mornings, with 18 each.

Climate for summer 2009-10

 

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.

February 2010: two rainy spells

The daily weather logWeather log February 2010

While last February was very hot then very cold, this February had no such weather. The only cool day was the 15th, at 25.6°.
Rain came in two short spells, totalling 55 mm in eight rain days (usually seven).

 Comparing February monthsClimate February 2010

This month’s average readings were normal. There were a few more cloudy mornings than usual, and the daily temperature range (13.3°) was down by one degree.
The rainfall total (55.0 mm) was in the 55th percentile for the month; above the February median (middle value) of 46 mm, but below the long-term February average of 67 mm. Rainfall totals for groups of months remain fairly high. The greatest rainfall shortage is the 12-month total (456 mm), which is in the 13th percentile.


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