June Weather Report

 In summary the month was pretty wet (in comparison to past Junes in Mallacoota) whether measured by rainfall or humidity, and warm - at least overnight.  Perhaps the Shire has its own mini La Nina?

Rain

In total my weather station recorded 102.8 mm of rain for the month.   The Bureau of Meteorology (BoM) scored 88.4 mm at the airport and 114.2 mm at Gabo Island.  To give a wider context Mount Baw Baw recorded 398.2 mm while lower stations in South and West Gippsland recorded somewhat over 110 mm.

My record is 138% of the median fall for the month and 103% of the mean (there. have been some big falls in the month of June (eg 309 mm in 1978 and 209 mm in 2007)).  

By the end of the month the pro-rata estimate of the possible fall for 2021 is 1236mm.  We have received 161% of the median fall Year to Date.

In addition to the actual fall the rain rate is interesting.  The two heaviest falls (10th and 11th) are both  82.2 mm/hr which is in the heaviest 2% of rates my weather station has recorded since February 2019.  That surprises me a little as I don't recall those days having noticeably heavy rain.

Temperatures

The overall measure of the temperature is the difference between the average temperature for the month and the long term average.  This was +0.59C for the month as a whole.  This next chart shows how that value developed through the month with the month-to-date value through the period: a cooler start and "settling" around 0.5C for the last third of the month

The next chart compares the BoM daily extremes with the long term averages.  It is clear that warm overnight temperatures are the issue.

 

Here are my WS extremes.  Reasonably similar to those for BoM.

Minimum Temperatures

The average overnight minimum temperature was 8.25C, well above the long term average of 7.25C.  It is however well below the highest average minimum recorded (8.86C in 2008).

The lowest minimum recorded for the month was 3.9C on 29 June.  This barely makes it into the coldest 10% of June minima (ranked 75th of 780 records).

Maximum Temperatures

The average maximum temperature at my WS was 16.3C.  Again well above the average (although the average is largely based on BoM records which tend to be a little lower than my WS).  However there are several past Junes with average maxima close to that value and the highest recorded average maximum was 16.74 in 2005.  

The highest maximum recorded for the month was 20.4C on the 8th. That is the 11th warmest June day (of 806 recorded maxima).

Humidities

The Relative Humidity for the standard times of 0900 and 1500are shown in the next chart.

I was initially surprised at how few 1500 records were below 60%.  However looking at the WS records for 2019 and 2020 this is quite normal.  That being said, the average values for rH for both times is well above the average for the last two years.  In looking at the 1500 graph be aware that it suffers from Murdoch syndrome: truncation of the vertical axis emphasises the extreme value!

Wind

The wind run for June is quite low, which is not that surprising, as the (very limited) data from BoM shows June to be one of the calmer months.  (The adjustment referred was to reflect the BoM site being more exposed to wind than my weather station.)

Our 'gut feeling' was that there had been some breezy periods in the month so I looked at  the daily wind runs for June 2021 and the average of June 2019 and 2020 (all measured by my WS).

In that chart the period 17-19 June stands out as having longer runs this year than on average in the past.  However there are several periods where the average of earlier years is longer.  Overall, 

• there are 16 (of 30) days with a longer run in 2021; and
• there are 7 days in 2021 with a run >100 km and 8 such days on average.

So overall I'd rate the year as pretty normal for June.

The pattern of wind direction was, like the humidity above a little surprising at first, when only looking at 2021, but on investigating was very similar to the previous 2 years.