We hope this doesn’t jinx it, but it has been a mild summer (so far).

You wouldn’t notice it if you just looked at average temperatures: on balance, readings in Central Park are 0.2 degrees Fahrenheit, above average so far this summer, according to New Jersey State Climatologist David Robinson, a professor of geography at Rutgers. But the number of scorchers is down drastically: the mercury has reached 90 degrees just four days this summer, while New York City typically experienced at least 15 such days in each of the last four years. (A historically normal summer would have 18 90-plus days from May through September, based on records going back to the 1870s.)

“We haven’t had that debilitating heat wave of multiple days over 90 that can be so dangerous to the young, the infirm, the elderly as well as those having outside jobs,” Robinson said.

New Jersey has seen an almost-normal summer, in terms of both average temperatures and days of extreme heat. But people throughout the region probably think this summer is even more mild than it is, Robinson said, because the last four summers have all been exceedingly warm.

A ripple in the jet stream that carries weather systems from west to east is to thank – or blame, for those who wish they could get more swimming time in. It shows a ridge in California, which is experiencing higher-than-average temperatures, and a trough in the Northeast. So, this doesn't mean we don't have to worry about climate change any more: the global average temperature for June, for example, was the highest on record.