Weather Wize

Cool start to December but warm to hot days on the way

By Peter Nelson

It has been a relatively cool start to December after one of the warmest spells during the latter half of November over Tasmania, Victoria, South Australia and the southern half of NSW.

Melbourne has had below normal maximum temperatures for the first 10 days of December and this has previously happened only 4 times in the last 158 years.

One of these in 1909 followed a significant warm November which also occurred in November this year.

There was heavy rain at the beginning of December 1909, which also happened this year in Melbourne and at most places in our regions.

There was a return to hot weather during the third week of December 1909 and again during Christmas and early in January 1910 with temperatures reaching 40 in our regions.

Much the same conditions are expected to happen in the coming weeks in our regions. The only significant rain being patchy falls and isolated thunderstorms close to mid December and early in January.

Hobart has had it's wettest start to December since 1941 after a warm dry November and Adelaide had it's coolest start to December also in 1941.

The latter half of December 1941 and early January 1942 saw many hot days of over 40 degrees and very little rainfall until the 19th January.

Melbourne's 98 mms rainfall to 9th December made it the wettest start to December since 1954 and the third wettest since 1860.

These two cases, 1860 and 1954, saw more rain in mid December and then a dry period until heavy rain and thunderstorms arrived close to Australia Day, 26th January.

Maximum temperatures were above normal the latter half of December and early January near 40 and again during the third and fourth week of January.

Humidity was notably high after the 3rd week of January in both those two cases.

It is more likely that this summer will closely follow the summer of these two cases rather than that of 1909-1910 and 1941-1942 summers mentioned above.