The year 2020 has brought a series of historically severe weather-related disasters all over the United States. In November, the 2020 Atlantic hurricane season set a new record for the number of tropical and subtropical storms in a single year. The 2020 wildfire season in the western United States burned millions of acres, and in California, five of the six largest wildfires in the state’s history occurred just this year. In the Midwest, an August derecho broughttorrential rain, hail, tornadoes, and sustained wind speeds over 100 miles per hour in Iowa and Illinois.
The severe weather events of 2020 are part of a larger trend—the frequency of extreme weather conditions in the U.S. is on the rise as climate change accelerates. According to the CDC, effects of climate change are likely to include more variable weather, heat waves, heavy precipitation events, flooding, droughts, more intense storms such as hurricanes, sea level rise, and air pollution.
Since the 1970's, the frequency of extreme weather conditions in the U.S. has risen
The frequency of extreme weather conditions in the United States has risen steadily since the 1970s, as demonstrated by the U.S. Climate Extremes Index (CEI). The CEI was developed to quantify observed changes in climate within the contiguous United States. The index includes temperature, precipitation, drought severity, and hurricane/tropical storm intensity. Based on these measures, extreme weather conditions have trended upward for nearly half a century, and four of the five highest years for this measure occurred within the last decade.
RELATED: Unhealthy weather conditions don’t have to follow you indoors. Use MERV 13 air filters for the best air quality inside your home.
Extreme weather is not just more common—it’s also bringing even greater financial impacts to the areas affected through property damage, business interruptions, and other economic losses. Through the first nine months of 2020, 16 weather and climate disasters produced losses exceeding $1 billion, according to NOAA's National Centers for Environmental Information (NCEI). This year is the sixth consecutive year with 10 or more billion-dollar disasters, an unprecedented milestone.
As both the intensity and number of severe weather events increase, so do the total costs of these disasters for the U.S. The same data from NCEI shows a dramatic increase in 5-year average costs associated with severe weather events over the past decade, from around $30 billion in 2010 to over $100 billion in 2020.
Not all states experience severe weather in quite the same way, and some are much more susceptible to highly variable weather conditions. To identify which states have the most extreme weather, researchers at Filterbuy created a composite score for each state. Using data from the National Centers for Environmental Information, researchers created an extreme weather score based on each state’s all-time maximum and minimum temperatures, maximum 24-hour precipitation, maximum 24-hour snowfall, and number of annual tornadoes per 10,000 square miles.
Here are the states with the most extreme weather.
Top 15 states with the most extreme weather
15. Maryland
State · Mid-Atlantic
Extreme weather score
55.5
Max temperature
109°F
Min temperature
−40°F
Greatest 24hr precipitation
14.8 in
Max 24hr snowfall
31.0 in
Tornadoes per 10k sq mi
9.9
Weather note
Maryland experiences a wide climate swing — from humid summers with tropical storm remnants to sharp winter cold snaps — making year-round air filtration important for maintaining indoor air quality. A MERV 11 filter changed every 60–90 days is a smart baseline for most Maryland homes. Shop MERV 11 →
14. Iowa
State · Midwest
Extreme weather score
56.3
Max temperature
118°F
Min temperature
−47°F
Greatest 24hr precipitation
13.2 in
Max 24hr snowfall
24.0 in
Tornadoes per 10k sq mi
9.1
Weather note
Iowa sits squarely in Tornado Alley with some of the most dramatic temperature swings in the country — blistering summers, brutal polar-vortex winters, and frequent storm systems that kick up agricultural dust and pollen year-round. A MERV 11 filter changed every 60–90 days is a strong baseline for most Iowa homes. Shop MERV 11 →
13. Texas
State · South
Extreme weather score
56.7
Max temperature
120°F
Min temperature
−23°F
Greatest 24hr precipitation
42.0 in
Max 24hr snowfall
26.0 in
Tornadoes per 10k sq mi
5.9
Weather note
Texas spans wildly different climates — from humid Gulf Coast storms and oppressive summer heat to arid West Texas and rare winter ice events. The state's massive size means air quality challenges vary by region, from tropical moisture to desert dust and occasional wildfire smoke. A MERV 11 filter changed every 60–90 days works well for most Texas homes. Shop MERV 11 →
12. Nebraska
State · Great Plains
Extreme weather score
56.7
Max temperature
118°F
Min temperature
−47°F
Greatest 24hr precipitation
13.2 in
Max 24hr snowfall
27.0 in
Tornadoes per 10k sq mi
7.4
Weather note
Nebraska sits in Tornado Alley with extreme temperature swings — scorching summers and polar-vortex winters that can dip past −40°F. Agricultural dust, spring pollen, and hail are common air quality challenges across the Great Plains. A MERV 11 filter changed every 60–90 days is a solid baseline for most Nebraska homes. Shop MERV 11 →
11. Montana
State · Northern Rockies
Extreme weather score
58.0
Max temperature
117°F
Min temperature
−70°F
Greatest 24hr precipitation
11.5 in
Max 24hr snowfall
48.0 in
Tornadoes per 10k sq mi
0.7
Weather note
Montana experiences extreme continental winters with record cold and heavy snow, plus dry summers with wildfire smoke drifting across the state. Despite fewer tornadoes, winter air stagnation and seasonal dust mean air quality shifts dramatically throughout the year. A MERV 11 filter changed every 60–90 days is a smart baseline for most Montana homes. Shop MERV 11 →
10. Missouri
State · Midwest
Extreme weather score
58.8
Max temperature
118°F
Min temperature
−40°F
Greatest 24hr precipitation
18.2 in
Max 24hr snowfall
24.0 in
Tornadoes per 10k sq mi
6.5
Weather note
Missouri sits at the crossroads of weather systems — humid subtropical summers, brutal polar-vortex winters, and frequent spring thunderstorms and tornadoes that can kick up significant moisture and dust. River valley locations experience stagnant air in winter, while spring and fall bring rapid pollen surges. A MERV 11 filter changed every 60–90 days is a strong baseline for most Missouri homes. Shop MERV 11 →
9. New Mexico
State · Southwest
Extreme weather score
58.8
Max temperature
122°F
Min temperature
−50°F
Greatest 24hr precipitation
11.3 in
Max 24hr snowfall
41.0 in
Tornadoes per 10k sq mi
0.9
Weather note
New Mexico's high desert climate brings scorching summers, extreme mountain winters with significant snow, and occasional dust storms that can reduce visibility and air quality dramatically. Wildfire smoke from regional fires also drifts into the state seasonally, making year-round air filtration important. A MERV 11 filter changed every 60–90 days is a solid baseline for most New Mexico homes. Shop MERV 11 →
8. Oklahoma
State · South-Central
Extreme weather score
59.2
Max temperature
120°F
Min temperature
−31°F
Greatest 24hr precipitation
15.7 in
Max 24hr snowfall
27.0 in
Tornadoes per 10k sq mi
9.0
Weather note
Oklahoma sits in the heart of Tornado Alley with high annual tornado frequency, extreme temperature swings, and intense spring and summer storm systems that bring heavy rain and hail. Wildfire smoke, agricultural dust, and moisture-laden Gulf air create variable air quality throughout the year. A MERV 11 filter changed every 60–90 days is a strong baseline for most Oklahoma homes. Shop MERV 11 →
7. Washington
State · Pacific Northwest
Extreme weather score
59.2
Max temperature
118°F
Min temperature
−48°F
Greatest 24hr precipitation
14.3 in
Max 24hr snowfall
65.0 in
Tornadoes per 10k sq mi
0.4
Weather note
Washington combines Pacific coastal moisture with mountain extremes — wet, mild winters on the coast and punishing snow in the Cascades and eastern regions. Wildfire smoke from regional fires also impacts air quality seasonally, especially in summer and fall. A MERV 11 filter changed every 60–90 days is a solid baseline for most Washington homes. Shop MERV 11 →
6. Kansas
State · Great Plains
Extreme weather score
63.7
Max temperature
121°F
Min temperature
−40°F
Greatest 24hr precipitation
12.6 in
Max 24hr snowfall
30.0 in
Tornadoes per 10k sq mi
11.7
Weather note
Kansas is in the heart of Tornado Alley with some of the highest annual tornado frequency in the nation, plus extreme temperature swings, severe spring thunderstorms, and significant agricultural dust. Hail, wind, and rapid pressure changes make air quality highly variable. A MERV 11 filter changed every 60–90 days is a strong baseline for most Kansas homes. Shop MERV 11 →
5. South Dakota
State · Northern Plains
Extreme weather score
64.5
Max temperature
120°F
Min temperature
−58°F
Greatest 24hr precipitation
8.7 in
Max 24hr snowfall
52.0 in
Tornadoes per 10k sq mi
4.7
Weather note
South Dakota experiences brutal continental winters with record-low temperatures and heavy snow, plus hot, dry summers and spring thunderstorms. Winter air stagnation traps contaminants, while spring and fall bring pollen and dust. A MERV 11 filter changed every 60–90 days is a strong baseline for most South Dakota homes. Shop MERV 11 →
4. Colorado
State · Rocky Mountains
Extreme weather score
67.0
Max temperature
115°F
Min temperature
−61°F
Greatest 24hr precipitation
11.9 in
Max 24hr snowfall
75.8 in
Tornadoes per 10k sq mi
5.1
Weather note
Colorado's high-altitude extremes bring record snowfall in mountain zones, thin air at elevation, and frequent wildfire smoke that drifts across the state seasonally. Elevation changes mean air quality varies dramatically by location — denver's lower elevation experiences different conditions than mountain communities. A MERV 11 filter changed every 60–90 days is a solid baseline for most Colorado homes. Shop MERV 11 →
3. Illinois
State · Midwest
Extreme weather score
67.8
Max temperature
117°F
Min temperature
−38°F
Greatest 24hr precipitation
16.9 in
Max 24hr snowfall
36.0 in
Tornadoes per 10k sq mi
9.7
Weather note
Illinois sits in the path of severe weather systems with high tornado frequency, extreme temperature swings, heavy spring thunderstorms, and significant winter snow. Lake Michigan influences coastal air quality, while interior regions experience agricultural dust and pollen surges. A MERV 11 filter changed every 60–90 days is a strong baseline for most Illinois homes. Shop MERV 11 →
2. Minnesota
State · Upper Midwest
Extreme weather score
68.6
Max temperature
115°F
Min temperature
−60°F
Greatest 24hr precipitation
15.1 in
Max 24hr snowfall
36.0 in
Tornadoes per 10k sq mi
5.7
Weather note
Minnesota experiences some of the coldest winter extremes in the nation, heavy snow, and Lake Superior's influence on coastal air quality. Summer humidity and spring pollen bring seasonal challenges, while winter air stagnation traps contaminants during cold snaps. A MERV 11 filter changed every 60–90 days is a strong baseline for most Minnesota homes. Shop MERV 11 →
1. California
State · West Coast
Extreme weather score
73.1
Max temperature
134°F
Min temperature
−45°F
Greatest 24hr precipitation
25.8 in
Max 24hr snowfall
67.0 in
Tornadoes per 10k sq mi
0.7
Weather note
California spans wildly divergent climates — Death Valley's record-breaking heat, Sierra Nevada snowfall, coastal marine layer, and some of the worst wildfire smoke in the nation that impacts air quality across entire regions seasonally. Regional variations are extreme, from desert dust to coastal fog. A MERV 11 filter changed every 60–90 days is a solid baseline for most California homes. Shop MERV 11 →
Methodology & detailed findings
To identify the states with the most extreme weather, researchers at Filterbuy created a composite score based on the following factors weighted equally:
