Climate change to blame for warmer, wetter spring weather

Experts say there is nothing strange about the high maximum temperatures in midspring resembling temperatures in mid-summer.

Natizel Nursery owner Gerhard Johnson said the rain was the only thing he looked forward to each year.

He said they had a good winter and hoped for a good summer. “I hope and pray we get enough rain this season because we need more feed for the horses, it’s a problem.

“It has to happen; it chases the bugs away and the fields are dry. We need the rain because the more flowers we grow, the better our sales are,” he said.

Associated professor in meteorology at the University of Pretoria Liesl Dyson said September was generally hot and dry over the interior of SA with one or two cold snaps.

“Such what happened in September 1981 when it even snowed in Pretoria. But the longterm average temperature in September in Pretoria is 26ºC, with the average rainfall just over 20mm,” she said.

“In short, what we are experiencing now is very much normal.” Dyson said SA was currently in a weak La Nina pattern, which meant SA expected a slightly above-average rainfall and maximum temperatures close to normal.

Vox Weather meteorologist Annette Botha said September was a month of ups and downs. “South Africans have experienced both hot and cold, rainy and sunny, humid and dry weather this past week.

According to National Oceanic and Atmospheric Administration, in 1970, about 30 spring days a year were warmer than normal. Now, that number is over 40 days,” she said.

Botha said spring was becoming warmer and wetter due to climate change. She said the daily highs and lows were caused by shifts in the intertropical convergence zone (ITCZ), cold fronts, Atlantic highs, Benguela current, Agulhas current and other weather patterns.

“Spring heat is becoming more common and above-average temperatures are becoming the new normal,” she said.

Botha said the long-term forecast suggests less-than-average rainfall for the southwest parts of SA during spring and above-average rainfall for the rest of the country.

She added above-normal rainfall was expected in late spring with significant rainfall forecast across north-eastern parts of the country with above-average maximum and minimum temperatures expected for most of the country.

Botha said the ITCZ started moving south at the beginning of October and brought summer rain.

“The ITCZ brings moist, unstable air more south and with the warmer weather expected during spring will cause thunderstorms to form over eastern South Africa. Rainfall in southern Africa is strongly influenced by the ITCZ,” she said.

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