Latest MetService and ensemble model guidance points to a daytime maximum of 15–16 °C in Wellington on May 18 under mostly clear skies and light southerly flow, keeping temperatures near or slightly above the May climatological average of 14 °C. Persistent cooler southerlies have limited daytime warming in recent days, while stable high pressure has maintained dry conditions and minimal cloud cover that would otherwise suppress the peak. NIWA’s seasonal outlook assigns a 50 % chance of above-average temperatures for the region through May, consistent with the current model consensus. The final high-resolution runs and any adjustments to the southerly component before Sunday will be the key variables that could shift the outcome between the tightly clustered 14 °C and 16 °C bands favored by traders.