All about Braidwood’s climate – a practical handbook and descriptive guide
Roger Hosking WDA
RRP $11.70. First published 2003. Revised edition 2017.
Reviewed by Jenny Goldie
Who better to write a book about Braidwood’s climate than the man who recorded the weather in Wallace Street for 30 years? This small book, with the addition of a CD, packs in all the information you ever needed to know about weather and climate in Braidwood.
Why is it important? Because farmers and horticulturalists need to know about weather, about rainfall, temperature, wind and evaporation.
It’s not just farmers. You need to know about the climate if you’re designing buildings and those planning outside activities. Better to plan an outside event for autumn, for instance, than in the spring when it’s more likely to be rained out.
Rainfall decreases the further you go from the coast, but increases with elevation. Despite being 35kms inland, Mt Budawang gets 150mm more rain than the coast annually because of its elevation.
Farmers will welcome this book for information on the effect of air temperature on plant growth. A bioclimate diagram for Braidwood shows the monthly average proportion of days which are either stressful or favourable to plant growth.
There is a section on bushfire risk that discusses the various weather factors that are conducive to the outbreak of fire. Relative humidity, air temperature, wind speed and instability of the atmosphere all interact with fuel quantity and fuel dryness.
South East Australia drying trend, temperatures going up
After 30 years of observing the weather, Hosking is convinced climate change is happening. While rainfall is not declining in Braidwood, he explains it thus: Braidwood is close enough to the ocean to benefit from the increase in rainfall caused by an increase in sea surface temperatures, but this is offset by the general drying that southeastern Australia is experiencing.
As for temperature, Hoskins himself measured a change between 1986 and 2015. There was a significant trend upwards of 0.08oC per year for maximum temperatures and 0.09oC for minimum temperatures.
There has been a slight change in wind direction, with winds from the north and west increasing in frequency, while those from the northeast declining. This is a matter of concern as a lot of Braidwood’s rain is associated with northeasterlies.
Changes in temperature are likely to be beneficial to farmers with a lengthening of the potential growing season providing, of course, there is no future decline in rainfall.
The book is available from the Braidwood newsagent and post office and several other businesses on the main street.