Spring is a more stable season than the fall

Let’s face it — spring can seem like a tease. Just when you think summer’s right around the corner, bam! Snow, ice or a blast of chilly air. Each thaw elicits cautious optimism, but for many, especially in the north, it’s a roller coaster of battling seasons.

Eventually, summer always wins out, but winter doesn’t go down without a fight. We often hear people joke that spring hardly exists, noting an abrupt transition from winter to summer.

Spring, is that you? Mild temperatures are set to spread over the eastern U.S. next week.

We looked into it to see whether that’s the case — that spring is often little more than flipping the switch between winter and summer. We found spring actually arrives and proceeds rather gradually and is rather stable compared with fall and winter.

What we looked at

In some parts of the country, it seems as though spring is an extra-turbulent time; clashing seasons and hefty temperature swings can bring the feel of all four seasons in a week. Data from five cities — Boston; Denver; Oklahoma City; Great Falls, Mont.; and Flagstaff, Ariz. — show spring isn’t a temperature ladder, but rather a series of uphill stair steps.

The change of the seasons, despite featuring dramatic fluctuations, is still rather gradual when the noise is smoothed out.

We reviewed average temperatures from the warmest and coldest point of each season to offer insight into seasonal range. That tells us about averages, but there’s more to the story.

We also looked at daily departures from average during 2020 from each of the cities we surveyed. The average for a date was derived from a smoothed version of 30-year climate normals powered by the National Oceanic and Atmospheric Administration.

Having a “normal” temperature on any given day is somewhat abnormal; averages are made up of a smoothing of lots of little overachieving and underachieving days that roughly balance out.

A transition time

Across the board in all cities we examined, the change in daily average temperature (the midpoint between typical high and low temperatures) was more dramatic in fall than in autumn. That said, spring was still an enormous transition time.

In Boston, the end of spring is about 29 degrees warmer than the start; for comparison, the coldest part of winter is just 11 degrees colder than winter’s mildest.

For most places, it seemed that once cold air became established in the winter, that was it. In Denver, for example, temperatures drop by 37 degrees in the fall and change by only 6 degrees in the winter. Then they typically warm 27 degrees in the spring.

Simply stated, spring is a period of big change, but fall features even bigger changes.

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How chaotic is spring?

In all of the five cities we reviewed, spring did feature chaotic weather, but, despite more stable average temperatures, winter proved to have much more irregularity.

In Boston, for instance, typical daily departures from average tended toward around 7.1 degrees above or below our smoothed “average” line in the wintertime. There was a little less average departure in the springtime and autumn — 6.2 degree. Summer, meanwhile, featured less temperature variability. Average daily departures from normal were around 5.2 degrees.

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For Oklahoma City and elsewhere, the results from 2020 were surprising — fall was actually more chaotic temperature-wise than winter. Spring was more “well-behaved” than both seasons, while summer, expectedly, was the least variable.

The same was true in Denver. Fall was the most chaotic season, then winter, spring and summer. Fall cold fronts across the Rockies and High Plains are notorious for bringing major temperature turnarounds. It’s not unusual for Denver to witness temperatures in the high 80s and snow in the same week.

Even Flagstaff exhibited the same trend — fall was a temperature roller coaster. Then came winter, spring and summer.

In the mountainous terrain of the Northern Rockies, it’s sometimes typical to see a more punctuated change of the seasons each spring once cold air is scoured out and replaced by warm air amid a larger pattern shift. We hypothesized that Great Falls would exhibit this tendency. Instead, we found that both fall and winter were very chaotic in 2020, while spring was more tranquil.

Extremes

Another way to compare the seasons is to look at extremes — and the difference between the highest high and the lowest low of a season.

In Denver, fall proved way more extreme than spring. It’s not uncommon to have 100-degree differences during meteorological fall between the highest-high and lowest-low temperatures. In 2014, a high of 94 and a low of minus-14 occurred in the same season.

In Boston, however, it was the opposite — you’re likely to find a greater absolute seasonal range in spring than fall. That’s particularly interesting, because fall has the greater average temperature change, but spring evidently has wilder temperature swings. It has to do with the moderating effect of the Atlantic Ocean, which is more pronounced in fall.

What it all means

All told, spring and fall are transition seasons. While fall, across the board, features a steeper temperature transition than spring, you’re more likely to see bigger extremes in spring in some places. Spring is a time of year when the jet stream is retreating north, dragging with it swirling storm systems and frequent temperature fluctuations.

The data shows that spring doesn’t arrive abruptly. Instead, it unveils itself little by little despite how it may feel.

Jason Samenow contributed to this article.