|May McLaren Vale (Pirramimma) Weather Station.|
The May recorded rainfall for McLaren Vale was close to median rainfall. The May rainfall records of the last 10 years show May to be a reliable month. Only May 2005 'missed out' and since 2006 the recorded rainfall has been close to the mean.
The May 2012 rainfall total in Adelaide (Kent Town) was slightly above average, with 62.8 mm received on 13 rain days. This is compared to the long-term average of 60.0 mm on 14 rain days, with a median rainfall of 59.8 mm. By comparison, during May 2011, 61.8 mm was recorded.
The wettest periods for the Adelaide and Hills region occurred during the first and last week of May. Much of the rainfall observed for the month came from cold frontal systems, followed by moist south to southwesterly airstreams being directed across South Australia. Despite the first week of May being wet, rainfall remained well below average across the Adelaide region up until the 23rd when a low pressure system with an associated cold front crossed the southern coastal regions of the State. This event produced significant totals in the Adelaide Hills in the persistent moist southerly airstream that followed.
Both maximum and minimum temperatures were mostly below average across the Adelaide Plains during May 2012, though tending to slightly above average at some locations in the Adelaide Hills. With respect to minimum (over night) temperatures, the coldest periods occurred between the 15th and 20th as a high pressure system maintained mostly fine and clear conditions across the State. The coldest period, with respect to daytime maximum temperatures, occurred in the latter period of the month when maximum temperatures were up to 6 °C below average in the wake of the passage of a cold frontal system.