THE WEATHER.

Star (Christchurch), Issue 20041, 2 September 1920, Page 4

THE WEATHER.

wwwi-.fr >. GAHtpRBURY CONDITIONS. (ByF. L- WOCIiES.) AUGUST WEATHER. August, considered by 75] any the first niouUi of spring, but in reality a winter month, 0;, it is included in the coldest quarter of the year, was unusually cold and wet, only three or four warm days being experienced, when northerly weather prevailed. It proved to he the coldest month of the winter, the average temperature not ranging so low for August since 19GS. The late winter this year has been remarkable for the continuity and sustained severity of the frosts, which have been experienced On the plains almost every night since the middle of July. On one or two occa.sions the frosts have been unusually severe for August, 17.5 degrees being registered in the city on the twentyj second- Throughout the month fre- ■ quont cold rains have fallen, the aggregate fall generally being considerably above the average. The rainfall in certain localities was excessive, especially on Banks Peninsula, where eleven inches were recorded at Akaroa, about thres r tiir.oß the monthly average'. In addition much snow has fallen on the higher portion of the back country, tbs ranges at the end of the month hearing an unusually heavy coating for so late in the season. Oh the lower levels of the hack districts there have beon frequent light to moderate falls of snow, while on one or two occasions the plains hove received a. coating. There were thrho well-marked stormy periods during the month, 1 nfunely, between the sixth and ninth, when a heavy cold south-east rain was recorded; the twelfth and fourteenth, when a similar but much colder storm occurred: and between the twenty-fifth and twenty, seventh, when north-easterly to southerly gales prevailed, during which interval the barometer fell lower than at any time since March 10, 191S, when the reading 'in Christchurch was 28.64. On the present occasion the barometer ! dropped to 28.70 in the city. Curiously enough, a similar type of weather conditions prevailed during both these periods of marked barometric minima, a heavy north-easterly gale being succeeded by a gale from the south-west quarter. On December 5, 1911, a barometric minimum of 28.65 preceded a violent north-west gale in the city. On June 19 last year the barometer fell to ,28.80. and preceded a heavy snowstorm which occurred on June 22. Even though bad weather is to bo expected with a very low barometer, the worst storms that the province has known have occurred when the barometric minimum has been 29.50 and over. During the heavy snowstorm of Juno 30July 2, 1018, when the upcountry districts were snowbound, the barometer went no lower than 29.60, while on July 22 and 23 of the same year, when the city experienced a record snowfall, the lowest barometric registration ’was about 29.50 immediately before the storm. All these readings, of course, a PPIy to a standardised mercurial bardmeter corrected to sea-level, allowance being made for altitude. To those who wonder why a. barometer so often belies its indications the writer desires to point out that the readings of one locality are not a. generally sufficient guide for weather changes, but when readings are obtained from over a wide area the differences recorded at a, par- 1 titular hour in .widely-separated localities give a better idea of probable changes, especially, when the correlation of such barometer readings is taken in conjunction with a knowledge of the movement and appearance of clouds and due allowance is ma.de for the physiographical features of a district. OUTLOOK FOB SEPTEMBER, . Expect very changeable weather during September. Occasional warm northwesters and one or two very cold southerly storms should be experienced. High winds likely to he of rather frequent occurrence. The rainfall should be somewhat above the average over a good part of the province.