Weather report March 2020

The month overall was quite dry (again!!!) and with quite moderate temperatures.  Humidity was normal  and while the month was windy that is expected around the equinox.

Rain

Overall my Weather Station recorded 35.2 mm which is 47% of average.  It is also much below last year's value for March.

Not surprisingly the pro-rata estimate for the year has taken a large dive over the month.

I have also looked at 12 and 36 month rainfall totals.  Both series bottomed out in December 2019 but has approached that level again after a miserable March total.  So I think it is possibly premature to celebrate the end of the drought.

Temperature

As a starting point here are the daily extreme temperatures over the month.

I see very little of note in those lines.  The daily range seems quite low, but it is difficult to compare with the BoM data, for which I have a long time series, as the afternoon sea breeze often restricts to maximum (and thus the range).  Somewhat to my surprise the average range this year 8.2^oC is actually wider than 2019 which comes in at 7.7^oC.

Another overall measure of temperature is the temperature anomaly defined as the difference between the current value for a measure and the long term average therefore.  Using BoM data for both values this resolves to 0.10 ^oC.  A chart of the progress of the anomaly through the month shows a warm start which soon "settles down" a little below 0^oC.

Most minimum temperatures were above average and most maximum temperature below average.  (Which logically implies that the range will be less than average.)  There was only one day in which the minimum was below average and the maximum above average.

Maximum temperature

The average maximum temperature for the month was 23.2⁰C.  Coming from my WS it is not surprising this was above the long term average.  It was almost idential to March 2019.

 Looking at the time series there is a slight (ie not significant upwards trend over the last 36 years.

 Minimum Temperatures

We were well below last year and a little above the long term average.

 Again the time series shows a non-significant upwards trend.

Humidity

Humidity was reasonably stable through the month with few high readings (as would be expected with little rain - to put the cart before the horse).  The most interesting observations were the few days in which the afternoon value was higher than the morning value.  They were following by high morning values so presumably reflect frontal activity

  The 0900 values were almost the same as last year and very little different to average.

 Afternoon values were well below last year (rainy) and average.

Wind

The chart accords with my memory of the end of the month being very windy.  My Great Big Anemometer (aka rotary clothes hoist) had already suggested that due to needing Frances to hold it still while I put out washing.  The run of 304 km on the 29th was the 11th longest run since I started the WS in February 2019 (the highest is 520 km last September followed by 470 km last March).

My WS is relatively sheltered compared to the BoM due to both the coastal location of the BoM station and it being at 10m above the ground while mine is about 2m.  So I have adjusted  the BoM readings to compare the two sites.   This shows March 2020 to be less windy than 2019 but slightly above average (allowing for the rubberiness of my adjustment to the BoM value they are the same).

The wind most frequently came from three directions this month.  (Note that where the slices are small the values overlap but the biggies are still legible.)

I will do an ad-hoc analysis of wind records in the near future.  To poke the data a little I have calculated the average speed for each direction.

It is possible that the absence of readings from ENE and E reflect the station being particularly sheltered from those directions.