The west of the state witnessed the worst of the heat as northerly winds dragged blistering heat from the interior.

Maximums reported at 3pm were widely shooting past 40 degrees. Most places saw them peak between 10 and 20 degrees above average.

East Gippsland saw a relatively 'cool' day with the mercury topping out in the 30s, but still up to 12 above average.

But in Western, directly in the path of the conveyor belt of heat:

- Port Fairy hit 44 degrees, 21 above average and their hottest in at least 19 years; and

- Cape Nelson surged to 42 degrees, their hottest day in 13 years.

Melbourne's 43.1 degrees set at 3.30pm was in the top 25 of all time, but still short of last February's record of 46.4 degrees.

With the heat and dry northerlies came the real threat of worsening fire conditions.

Colac, by mid-afternoon had reached a catastrophic fire danger rating.

Many parts through the west hit severe or even extreme.

Lighter winds than Black Saturday have allowed for generally better conditions though.

A cooler change will move through on Tuesday bringing much needed respite.