Page:Hunt - The climate and weather of Australia - 1913.djvu/22

 Brisbane experiences the highest annual mean maximum temperature with 78°; Adelaide and Perth follow with 73°; Sydney, 70°; Melbourne, 67°; and Hobart, 62°. But the extremes take a different order. Adelaide comes first, with a maximum of 116°; Melbourne, 111°; Brisbane, 109°; Sydney and Perth, 108°; and Hobart, 105°.

The lowest shade temperatures recorded are as follows:—Melbourne, 27°; Hobart, 27°; Adelaide, 32°; Perth, 35°; Sydney and Brisbane, 36°.

 III.—GENERAL VARIATION IN PRESSURE.

At only a few important stations in each State are complete barometric data available for any length of time. These have unfortunately been taken out for differing times of the day.

The twelve monthly charts herewith are therefore only approximations, the data being as follows:—

The general features of the average monthly isobars as shown on the charts will be briefly discussed; but in these charts the curves are necessarily much smoothed, and many interesting constant local characters can be better investigated from a much more detailed series prepared for one year. (This is done for 1910 in later paragraphs.) Some of the charts for the year are given in figures 29-31. The annual fluctuations of mean barometric pressure for the State capital cities is given in the annexed graph (Fig. 28).

In January (midsummer) a depression of a monsoonal nature occupies North-west Australia. The Antarctic belt of lows reaches to the South Coast of Tasmania. The warm high land in the south-east appears to give rise to a col of low pressure separating anticyclonic foci over the Bight and over the North Tasman Sea. In February, the conditions remain much the same. In March, the northern low has moved off the continent to the north-west and the anticyclones have strengthened considerably over the two foci. In April a closed high is forming over the south-east of the continent, and elsewhere the isobars run across Australia from west to east.

