This week's hot weather comes less than a week before the start of summer, but how unusual is it for June?

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Tuesday was the third day this season that some areas of New Jersey hit 90 degrees, but state climatologist David Robinson of Rutgers University said that's actually a little late to be seeing widespread readings in the 90s for the first time.

The highest temperature in the state thus far this year is 92 degrees, recorded in Hillsborough on June 3, but that number is likely to be surpassed this week.

Robinson said the average summer high around here, even in the middle of July, is only in the upper 80s.

"The last time we had a string of a week or more of days with temperatures of 90 or above was the third week of July last year," Robinson said.

So what does he consider a real heat wave in New Jersey?

"It's when you start stringing it together, five or 10 days over 90 in June, that's unusual," said Robinson, who added that it is also out of the ordinary for the urban corridor of New Jersey to go the full month of June without a day over 90 degrees.

Robinson calls this week's weather a "mini heat wave" to kick off the season. Summer officially begins this Saturday.