Extreme Weather Toolkit: Heavy Rain and Flooding

Climate change is bringing heavier rainfall extremes and increased, inequitable flood risk to many parts of the U.S. 

For every 1°F of warming, the air can hold an extra 4% of moisture, increasing the possibility of heavier downpours that can result in flooding. 

As the climate has warmed from 1958 to 2021, the heaviest 1% of downpours have intensified in every major region in the continental U.S., led by the Northeast (+60%) and Midwest (+45%). Extreme daily rainfall has also  become more frequent across the country since the 1980s, and  hourly rainfall rates have increased by 15% on average across 126 U.S. cities analyzed by Climate Central.

This hazardous intensification of rainfall is expected to continue with future warming. With 2°C (3.6°F) of warming, U.S. counties are likely to see an average of 17% more precipitation falling during the heaviest rainfall events. The latest IPCC reports indicate that precipitation extremes are likely to increase globally, even in some regions with decreasing average precipitation.

While increases in heavy rainfall don’t always translate to increases in flooding, since flood risk depends on a number of factors, with high future levels of heat-trapping emissions, U.S. flash floods could also intensify — especially in the Southwest.  In the U.S., people of color and those living in mobile homes are disproportionately exposed to flood risk, especially in the South and in rural areas. A recent study suggests that the burdens of increased U.S. flood risk by 2050 could disproportionately impact Black communities along the Atlantic and Gulf coasts.

Changes in rainfall from 1988 to 2017 accounted for one-third of U.S. flood damages (about $73 billion) over that same period. And the most intense downpours caused the largest damages. 

Updated: May 2025

Resources

These resources explore the science, trends, and local impacts of heavy rain and flooding in the U.S.

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Climate Matters

Heavier Rainfall Rates in U.S. Cities

Hourly rainfall intensity — a key factor in flash floods — has increased since 1970 in cities across the U.S.

Climate Matters

More Downpours: Increase in Heaviest Precip Events

The number of days each year with extreme rainfall is, on average, increasing in every region of the U.S.

Climate Matters

Climate Change and Inland Flooding

Flooding is costly, damaging, and deadly. It affects much of the U.S. and is likely to intensify with warming and shifting rainfall patterns.

Report

Climate Change and Children's Health: Flooding

Storms and flooding events fueled by climate change bring increased health and safety risks for children.

Climate Matters

Atmospheric Rivers

Atmospheric rivers bring both vital water resources and deadly hazards—especially in the western U.S.

Climate Matters

Changing Seasonal Normals

To kick off meteorological winter, Climate Central looks at changing seasonal normals, finding that every season—especially winter—was warmer during 1991-2020 than during the previous 30-year period.

Climate Matters

After the Storm: Damp, Moldy Homes

Extreme weather events fueled by climate change bring health risks—including from damp, moldy homes after storms and floods.

Climate Matters

Wettest Seasons in U.S. Regions

Water supplies, agriculture, and ecosystems all rely on precipitation. Explore seasonal precipitation patterns in U.S. states and regions and see how they’re changing.

Report

Report: Wetter Rainfall Hours in a Warming Climate

Climate change is supercharging the water cycle, leading to heavier rainfall extremes in many parts of the U.S.

Climate Matters

Wetter Rainfall Hours in a Warming Climate

New analysis shows that hourly rainfall intensity—a key risk factor in flash floods—has increased since 1970 at 90% of 150 U.S. stations analyzed by Climate Central.