How climate change is making spring warmer, rainier and earlier

Spring is the season of change. It serves as a transition period between winter’s frigid cold and the sweltering heat of summer.

But spring itself is also going through a transformation of sorts. Like everything affected by climate change, spring is different than it used to be. So as we kick off another season of warming temperatures, budding flowers and cooling rains, here’s a look at how spring has changed.

It’s starting earlier

The official start of spring on the calendar hasn’t moved, of course, but the greenery that we associate with the season is arriving sooner than it used to.

Climate change has disrupted the natural rhythms of the seasons. Though the impacts vary from year to year, in general, winter is becoming warmer and shorter. That means the cold that prevents plants from thriving is less intense and is fading away earlier.

Scientists at the Environmental Protection Agency have found a way to quantify this change. Using records of life cycles of honeysuckle and lilac plants from across the country going back to the middle of the 20th century, they have marked when these plants start to show signs of bouncing back from winter (what they call the first leaf) and when they sprout flowers (called the first bloom).

In most of the country, first leaf and first bloom are happening earlier today than they used to. How much earlier spring is arriving varies quite a bit. In some parts of the West Coast and the central Plains, first bloom is coming several weeks — or even a full month — earlier. On the other hand, flowers are sprouting later in certain areas of the Upper Midwest.

More favorable conditions for plants also means more challenges for allergy sufferers. On average, plants start to release pollen about two weeks after they emerge from their winter dormancy. The earlier start means that spring allergy season is becoming “longer and more intense,” according to the EPA.

It’s getting hotter

Along with autumn, spring is often known as a “shoulder season” because of its moderate temperatures relative to winter and summer. While that’s still true — especially as the extremes of those other seasons become more intense — spring just isn’t as temperate as it used to be for most of the country.

The average national temperature for each of the spring months has gone up by several degrees since the middle of the last century. Weather varies from year to year, but the overall trend is clear. The changes are especially pronounced in the early stages of the season.

How much hotter things have become varies by location. Comparing average spring temperatures from 1950 to 2024 offers a snapshot of how dramatically things have changed. The most significant shift is found in states like Michigan and Minnesota, where temperatures are more than 13 degrees higher. Only two states, California and Arizona, saw their average temperatures go down, and only by a slight amount.

It’s getting wetter

Warm spring rains are one of the signature joys of the season. At a national level, climate change has meant more spring showers than in the past.

But those nationwide totals hardly tell the full story. A deeper dive into the data shows that spring rains have really become more concentrated in places that already saw the most precipitation. Spring rains have decreased significantly in the Southwest and the Gulf states, making droughts in the most arid parts of the country more severe. Those reductions are offset, and then some, by increased rain in the Midwest and Pacific Northwest.

This year’s spring weather is expected to fit within these patterns. The National Oceanic and Atmospheric Administration issued new forecasts for the next three months on Thursday that predict higher-than-normal temperatures for most of the country along with less rain in the Southwest and more for parts of the Midwest.