Why have there been so few 90 degree days in Boston this summer?

By Terry Eliasen, Meteorologist, WBZ-TV Exec. Weather product

BOSTON – If you love hot, sunny summer days, this year was clearly not your favorite year.

The summers of 2022 and 2023 couldn’t be more different.

This time last year, we were in the middle of a drought. This summer, we’re challenging all-time monsoon rainfall records in Boston and Worcester.

By this date last summer, Boston had had 19 days of 90 degrees or higher, including a 6-day and 7-day heat wave. This summer, the city reached 90 just 4 times.

If we were to finish the year with just four 90+ days, that would tie Boston for at least fourth place all-time.

Looking ahead to the next 10 days, there is a very small chance that temperatures will rise to near 90 degrees.

Take a look at the past ten years. Boston averages about 15 90+ days a year, and the city recently broke that number. This summer sticks out like a sore thumb any way you cut it.

The weird thing is, I don’t think this summer will be remembered as “awesome.” It has been very humid most of the time, even when the temperature is below average for the day, it still feels sticky.

Do we blame El Nino? It’s definitely a factor. El Niño is known for causing all kinds of global climate disruptions.

What about climate change? It is difficult to link a single storm, or even a single season, to changes taking place at the global level. One thing I would say is that extreme events (precipitation, temperatures, drought, etc.) are certainly more likely to occur with a warmer planet and even more so with a warmer ocean. Global ocean temperatures have now reached levels never seen before. We cannot compare weather patterns now to any other time in our recorded history, simply because our oceans have never been this warm.

Blame Jetstream

In simpler terms, the weather pattern has been pretty much “stuck” for most of the summer.

I’m sure you’ve heard of the “heat dome” that started over parts of the southwestern United States and is now located in the middle of the country.

While those areas were baking in 100-degree heat day after day, New England was largely on the other side of the Jetstream or directly beneath it.

Typically in the summer, we see a repeat of the “Bermuda High.” This is what pumps hot air to the northeast. This was not able to hold up this summer. Instead, high pressure was nearly stationary over the central United States.

Is summer over? Can we kiss the 90 degree days goodbye?

I’m not ready to put a fork into the season just yet. Would anyone be shocked if the real heat suddenly arrived, in September, as the kids went back to school?

I will not do that.