We have been tracking first leaf and first bloom dates from this spring across the United States. For the final post in this series we explore how and why these ecological milestones have been shifting in recent years.
The map above compares the average leaf-out date for the most recent 30-year climate normals (1991-2020) to the 20th-century average (1901-2000) for more than 500 stations across the contiguous United States. Orange shows locations where the first leaves emerged earlier in recent decades than they did in the 20th century. Purple shows locations where leaves emerged later. The bigger the circle, the bigger the difference from average.
The graph shows the first-leaf trends across the Southeast compared to the rest of the contiguous U.S.
Read more about what is causing these early or late shifts by clicking the "Event Tracker Stories" link in our bio.
On November 19, 2023, a massive heat wave resulted in Brazil’s highest recorded temperature in history, 112.6 degrees Fahrenheit (44.8°C). Climate change and El Niño were factors in producing the heat wave. The first image in this post is an homage to Salvador Dalí’s The Persistence of Memory.
Extreme heat is worsening around the world and the stakes for heat safety are higher now than ever.
Heat-related incidents at outdoor events, both in the United States and internationally, are forcing the private and public sectors to confront the growing challenge of heat governance.
According to the annual report from @noaadata , 2024 was the warmest year since global records began in 1850. July 2024 was the warmest July for the globe in @noaa 's 175-year record, and July 22 was Earth’s hottest day on record.
As summer arrives, hotter than average temperatures are predicted across the U.S., according to NOAA NWS Climate Prediction Center. The second and third images show the number of people under extreme heat alerts on June 23, 2025 as an extreme heat wave engulfed a large portion of the eastern U.S.
Learn more about how event organizers are partnering with meteorologists and researchers to keep people safe by clicking the "News & Features" link in our bio and clicking on the "Keeping fans safe in a warming world: a growing challenge for outdoor events" story.
June 21 is Show Your Stripes Day, a day intended to spark conversation about how our world is warming unusually rapidly due to human emissions of heat-trapping gases (like carbon dioxide).
This visualization shows how temperature data for the United States transforms into the stripes visualizations you may see today and tomorrow. The graph shows the average annual temperature anomalies for the contiguous United States from 1895 to 2024, compared to the 20th-century average. Blue bars indicate the years where temperatures were below normal, red bars indicate the years where temperatures are above normal. The colors of each bar have been scaled to show how much cooler or warmer the average temperature anomalies are, the darker the blue or red the greater the temperature difference from average.
The coldest year was 1917, where the average annual temperature was 50.05°F, which is 1.96°F below the 20th-century average. This is the darkest blue line. Last year (2024) was the warmest year on record with an average annual temperature of 55.5°F, 3.49°F above the 20th-century average. This is the darkest red line.
Climate scientist @climatehawkins , at the University of Reading, first created these iconic warming stripes. This is our representation of the warming stripes utilizing @noaadata for the contiguous United States.
When will it rain? Where will it rain? How much will it rain? Will the precipitation fall as rain, snow, or sleet? The answers to these questions are needed by every person and business in the United States and at almost every timescale, spanning from the next hour to daily to decadal.
The need for accurate precipitation forecasts has been increasing, yet the skill of seasonal precipitation forecasts have remained stagnant since the late 1990s.
NOAA's Climate Program Office is working with partners nationally and internationally to improve this precipitation forecast accuracy in order to better prepare for extreme rain, floods, and droughts.
Read more by clicking the "News & Features" link in our bio.
ENSO-neutral conditions are expected to continue through summer.
While the odds of La Niña increase through the fall, the odds of neutral conditions continuing slightly outweigh those of La Niña. By the November to January period, there’s a 48% chance of neutral and a 41% chance of La Niña, with El Niño a distant third.
Read more about what ENSO-neutral conditions mean for seasonal prediction by clicking the "Latest ENSO Blog" link in our bio.
The first blooms of spring were earlier than average across most of the Northeast: https://www.climate.gov/news-features/event-tracker/first-blooms-2025-spring-season-were-earlier-average-across-most-united
Now that the spring growing season has passed, we invite you to compare this year's leaf-out dates to the first bloom dates for common garden plants—lilacs and honeysuckles.
The leaf-out map resembles a layer cake, with alternating bands of color: purple where leaf-out came later than average, and orange where leaf-out came earlier. The timing was linked to regional weather events that chilled some areas and warmed others.
Compared to leaf emergence, the arrival of the first blooms of 2025 were more consistent across the country, with most areas seeing earlier-than-average emergence of these plants’ first flowers of the season. This early flowering is consistent with the warmer-than-average March and April experienced across most of the contiguous United States.
Comparing this year's map of first leaf to first bloom, you see many places where these two indicators of spring were in sync, meaning first leaves and blooms were both early, or were both late.
Less common were areas where first leaves were late, but first blooms were early.
What was extremely rare this spring—so rare that we couldn’t find a good example just by visually comparing the two maps—was the combination of early leaves, but late blooms.
If you find an example let us know in the comments!
Read more about how weather conditions this year impacted leaf-outs and first blooms by clicking the "Event Tracker" link in our bio.
As we head into summer and typical hot weather, what’s ahead for June?
Will we see a hot start to the summer, or will the relatively benign temperatures of May persist? Will beneficial rains continue to improve the state of drought across the nation, or will hot and dry weather result in drought expansion?
Here’s what NOAA’s Climate Prediction Center (CPC) expects to occur during June.
https://www.climate.gov/news-features/understanding-climate/us-climate-outlook-june-2025
Like all tornado outbreaks, the “where and when” of the outbreak in mid-March 2025 depended on the overlap of multiple tornado-friendly conditions, shown in this map pair. Our latest ENSO blog explains how La Niña can make these conditions more likely.
Read the blog by clicking the "ENSO Blog" link in our bio.
The U.S. wildfire season isn’t just about fiery flames. It also brings thick toxic haze and smoke that can travel hundreds of miles and lead to dangerous air quality across the country. But have you ever stopped to think what’s actually in that smoke?
Amber Liggett takes a deep dive into the makeup of wildfire smoke and what scientists are uncovering about how it affects our health.
Read more by clicking on the “News & Features” link in our bio.
Sea surface temperatures in the key ENSO-monitoring region of the tropical Pacific were just a little cooler than average (blue areas) in April, but not enough to qualify as La Niña. The rest of the global ocean is mostly warmer than average (orange, red). Read more about what “ENSO-neutral” means in our latest blog by clicking the "ENSO Blog link" in our bio.
