May 2024 WEATHER REPORT

On average it was quite an average month!  Of course that can simply means that the highs and lows balance each other which is the pretty much the case with temperatures.  Dampness, measured by rainfall or humidity, was a little higher than normal.

Rain 

We ended the month with 80.4mm of rain amounting to 114% of median.  Perhaps best described as a little above average.

Looking at a time series of rainfall for May the outcome for 2024 is not outstanding.

I have also looked at the monthly totals for some nearby sites.

site	Fall (mm)
BoM airport	82.6
BoM Gabo	96.2
Clarke St	83.8
Angophora Dr	80.4

The Gabo site shows a fall of 26mm on 13 May while the other 3 sites show 0.2mm for that day.  I think this is a recording error and have reported it to BoM.

I have also used pro-rata estimation to guess the likely annual fall.  I have removed the earlier part of the series as it is distorted by some heavy falls in January.

 It is showing an interesting pattern as systems hit the area and are then followed by a dry spell.  The current value (779mm) is well below the annual median (904 mm) and the total fall year to the end of May is 92% of the median fall for that period.

Temperatures

The anomaly for the month ended at +0.22C, so a little bit warm.  The development of the anomaly through the month shows gradual recovery from a very cold start.

The anomaly Time Series still shows an upwards trend in the 12 month moving average: this appears to be in line with expert opinion (at least as reported by the ABC).

The historic daily maximum and minimum values for the month have a fairly strong downwards trend through the month.  That is shown (but not significantly) for the daily minimums for this month but the daily maxima show a weak upwards trend - not surprising given the very high values for the last two days of the month.

I have begun to pay some attention to the daily ranges of temperatures, but have not yet worked out a standard approach to examining them. Here are the historic and current ranges.

The relative stability of the historic series and fluctuations in the 2024 series are to be expected.  An interesting point - and an example of an issue I need to work on - is the comparison of 31 May with the preceding three days.  The range for the 30th is small because of a high value for the minimum on that day (which occurred at 2200hrs!).  I shall try to compile a special report on this topic.

Minimum temperatures

The lowest temperature recorded in the month was 5.8C on the 27th, while the average minimum was 9.13C a little below the long term average and a little above 2023.

There were 6 days in which the minimum was >1SD below the monthly average (mainly towards the end of the month) and 3 days in which it was >1SD above the average.  None of these coincided with maxima of similar significance.

Restricting the observations to the 6 years for which I have records from home shows average minima quite tightly grouped between 9C and 10C, with 2024 in the mix.

Maximum Temperatures

The highest maximum temperature for the month was 24.1C on the 29th: very warm for that end of the month.  The 30th at 23.5 C was also hot for the date.  The average temperature for the month was 18.9C, above average and well above 2023.  However even deleting those two extremes the average was still 0.3C above average: so a warm set of maxima.

There were 5 days in which the maximum temperature was >1SD above the average for the month, three of which were 28th - 30th.  Only 1 day with a maximum >1SD below the average.

Again restricting observations to my records from home, 2024 is on the upper edge of the series.

Humidity

A rather humid period especially in the early part of the month. The very high afternoon readings coincide with one of the rainy periods. 

Both of the charts for the standard times show this month to be more humid than average and 2023.

Wind

According to my WS this was the least windy month - by a considerable margin - since I started recording.  I suspect this is an artefact of the relatively poor exposure to wind.  And will not be analysing this further.