Scoresby set a new record for the highest May minimum, as Melbourne enjoyed a night that would be considered warm in summer. All of the Melbourne area had another unseasonably warm night with most suburbs staying above 15 degrees, between six and 11 degrees above the May average. Many suburbs, including the CBD, had a warmer morning than the May daytime average. Since Wednesday night Melbourne has stayed more than five degrees above average each night, with residents kicking off the doona in the summer-like temperatures. Scoresby was the most extreme, setting a new May record in its 46 year old history, only getting as cool as 17.6 degrees. This is staggering considering we are into the second half of the month. Coldstream and Sheoaks both came within 0.4 degrees of breaking their respective records, of which data goes back at least two decades. Last night was warmer than the February average in all suburbs. The reason for the unseasonably warm weather, which is not limited to overnight conditions, is a blocking high in the Tasman Sea. This high pressure system has remained off the New South Wales coast for a number of days, drawing warmth from the north of the country into the south. The warm air mass then combined with the cloud cover from a nearby trough to produce the very warm night. The next two nights are looking almost as warm as last night. The warm northwesterly winds experienced last night will continue. The only thing that might allow the temperature to fall somewhat is that there should be less cloud. On Tuesday, a cold front will arrive, bringing an end to the unseasonably warm weather for a few days. However. that stubborn high to the east will see the warmth flood back in again from Thursday to Saturday before a stronger front brings some more seasonable weather.