State ranking · Updated

The Hottest States in the US, Ranked by Heat & Hydration Risk

What are the hottest states in the US, and which face the most heat and dehydration risk? We ranked 49 states on summer heat, heat deaths and older populations using NOAA, CDC and Census data.

By Hydrate · Sources: NOAA, Census Bureau, CDCState index (CSV)Cite thisPress contact

Arizona

Ranks #1 of 49 states, scoring 93 out of 100.

Hydrate Heat & Hydration Risk Index

93.8°F

Average summer high in Arizona and Texas, the hottest states.

NOAA, 1991–2020 normals

4.5

Heat deaths per 100,000 people a year in Arizona, the highest rate.

CDC, 2018–2022

#11

Texas: as hot as Arizona in summer, but fewer heat deaths and a younger population put it lower.

Hydrate index

What we found

  1. The hottest states in the US by average summer high are Arizona (93.8°F), Texas (93.8°F), Oklahoma (91.8°F), Louisiana (91.3°F), Florida (91.1°F).
  2. Arizona ranks #1 for heat and hydration risk, with a score of 93 out of 100.
  3. The rest of the top five: New Mexico (80), Arkansas (77), Mississippi (76), Louisiana (74).
  4. Minnesota has the lowest risk of the 49 states scored.
  5. Arizona had the highest heat death rate: 4.5 per 100,000 residents a year in 2018–2022, about 23 times the typical state's.
  6. Washington's summer of 2025 ran 2.9°F above its 1991–2020 normal, the largest jump of any state.

What are the hottest states in the US?

By average summer high, the hottest states are Arizona, Texas and Oklahoma. Heat alone doesn't set the risk ranking below: it also counts heat deaths and how many older residents a state has.

Top 10 hottest states in the US

Average summer (June–August) high temperature, 1991–2020 normal, °F. Source: NOAA NCEI Climate at a Glance. Hawaii is not covered by NOAA's statewide series.

  • 1. Arizona93.8°F
  • 2. Texas93.8°F
  • 3. Oklahoma91.8°F
  • 4. Louisiana91.3°F
  • 5. Florida91.1°F
  • 6. Mississippi90.5°F
  • 7. Alabama89.8°F
  • 8. Georgia89.8°F
  • 9. Arkansas89.7°F
  • 10. South Carolina89.7°F

Heat risk by state: the map

Heat & Hydration Risk Index, by state

Score 0–100; higher means more risk. Hawaii and DC are not covered by NOAA's statewide temperature series and are not scored. Data as of 2026-10-14.

Arizona: 93 (rank 1)AZ93New Mexico: 80 (rank 2)NM80Arkansas: 77 (rank 3)AR77Mississippi: 76 (rank 4)MS76Louisiana: 74 (rank 5)LA74Nevada: 72 (rank 6)NV72Oregon: 71 (rank 7)OR71Alabama: 69 (rank 8)AL69South Carolina: 68 (rank 9)SC68Oklahoma: 66 (rank 10)OK66Texas: 63 (rank 11)TX63Wyoming: 62 (rank 12)WY62Missouri: 61 (rank 13)MO61Vermont: 61 (rank 14)VT61California: 60 (rank 15)CA60Tennessee: 59 (rank 16)TN59Kansas: 58 (rank 17)KS58Florida: 57 (rank 18)FL57Maryland: 57 (rank 19)MD57Delaware: 53 (rank 20)DE53West Virginia: 52 (rank 21)WV52Pennsylvania: 51 (rank 22)PA51South Dakota: 51 (rank 23)SD51Montana: 50 (rank 24)MT50Washington: 50 (rank 25)WA50Kentucky: 49 (rank 26)KY49Iowa: 48 (rank 27)IA48Indiana: 45 (rank 28)IN45Utah: 45 (rank 29)UT45Idaho: 43 (rank 30)ID43Rhode Island: 43 (rank 31)RI43Nebraska: 41 (rank 32)NE41Georgia: 40 (rank 33)GA40Ohio: 39 (rank 34)OH39Illinois: 38 (rank 35)IL38North Carolina: 38 (rank 36)NC38Maine: 37 (rank 37)ME37Wisconsin: 37 (rank 38)WI37New Hampshire: 36 (rank 39)NH36North Dakota: 35 (rank 40)ND35Virginia: 35 (rank 41)VA35Colorado: 34 (rank 42)CO34Connecticut: 31 (rank 43)CT31Michigan: 29 (rank 44)MI29Massachusetts: 28 (rank 45)MA28New Jersey: 28 (rank 46)NJ28Alaska: 27 (rank 47)AK27New York: 25 (rank 48)NY25Minnesota: 18 (rank 49)MN18District of Columbia: not scoredDC–Hawaii: not scoredHI–
  • 80–100
  • 60–79
  • 40–59
  • 20–39
  • 0–19

The 10 highest-risk states

Heat & Hydration Risk Index score, out of 100.

  • 1. Arizona93
  • 2. New Mexico80
  • 3. Arkansas77
  • 4. Mississippi76
  • 5. Louisiana74
  • 6. Nevada72
  • 7. Oregon71
  • 8. Alabama69
  • 9. South Carolina68
  • 10. Oklahoma66

Find your state

Full ranking

RankStateScoreSummer high, normalSummer 2025 vs normalAged 65+Heat deaths per 100k a year
1Arizona9393.8°F+1.9°F19.7%4.50
2New Mexico8087.6°F+0.7°F20.1%0.56
3Arkansas7789.7°F+0.8°F18.2%0.58
4Mississippi7690.5°F+1.0°F18.1%0.41
5Louisiana7491.3°F+0.6°F17.8%0.49
6Nevada7286.4°F+1.6°F17.6%3.77
7Oregon7178.5°F+2.7°F19.9%0.78
8Alabama6989.8°F-0.3°F18.5%0.35
9South Carolina6889.7°F-0.5°F19.8%0.30
10Oklahoma6691.8°F-1.1°F16.9%0.41
11Texas6393.8°F-0.4°F14%0.35
12Wyoming6278.5°F+2.0°F20%≤0.31
13Missouri6186.4°F+0.5°F18.7%0.29
14Vermont6175.9°F+2.4°F22.9%0.31
15California6088.6°F+1.1°F16.5%0.30
16Tennessee5986.8°F+0.7°F17.6%0.30
17Kansas5889.2°F-0.8°F18%0.29
18Florida5791.1°F+0.9°F21.8%0.12
19Maryland5784.8°F+0.1°F17.6%0.37
20Delaware5385.1°F-0.4°F21.7%≤0.17
21West Virginia5281.8°F+1.9°F21.9%0.15
22Pennsylvania5180.4°F+1.0°F20.4%0.19
23South Dakota5182.7°F+0.2°F19%0.24
24Montana5078.1°F+0.7°F21.2%0.25
25Washington5075.8°F+2.9°F17.3%0.55
26Kentucky4985.8°F+1.1°F18%0.17
27Iowa4882.1°F+0.6°F18.9%0.20
28Indiana4583.4°F+1.2°F17.6%0.19
29Utah4585.0°F+2.4°F12.4%0.18
30Idaho4378.3°F+2.3°F17.8%0.23
31Rhode Island4379.6°F+0.9°F19.8%≤0.16
32Nebraska4184.7°F+0.3°F17.4%0.18
33Georgia4089.8°F+0.1°F15.8%0.14
34Ohio3982.5°F+1.2°F19.1%0.12
35Illinois3884.4°F+0.8°F17.9%0.14
36North Carolina3886.5°F-0.2°F17.9%0.13
37Maine3775.1°F+1.7°F23.5%≤0.13
38Wisconsin3778.3°F+0.2°F19.6%0.17
39New Hampshire3677.0°F+1.6°F21.5%≤0.13
40North Dakota3579.3°F-0.5°F17.6%≤0.23
41Virginia3584.5°F+0.3°F17.6%0.14
42Colorado3480.9°F+1.4°F16.5%0.16
43Connecticut3180.5°F+1.2°F19.4%0.05
44Michigan2978.3°F+1.0°F19.6%0.11
45Massachusetts2879.6°F+1.2°F18.7%0.06
46New Jersey2883.5°F+0.2°F18%0.09
47Alaska2760.0°F+0.3°F14.8%≤0.24
48New York2577.7°F+1.6°F18.9%0.09
49Minnesota1878.0°F-0.1°F18.2%0.09
–District of Columbia–––12.9%≤0.26
–Hawaii–––21.5%≤0.12

Download the full dataset: State index (CSV).

Why heat matters

4 figures

The national picture behind the state ranking.

  1. 2,325

    2,325 people died of heat-related causes in the US in 2023, the most in any year since at least 1999 and more than double the 1999 count.

    Heat listed as an underlying or contributing cause on death certificates (CDC WONDER, 1999–2023); 2023 figures were provisional at publication. CDC later reported 2,391 heat-related deaths for 2024, under a definition it doesn’t state, so the two years aren’t directly comparable.

    JAMA, 2024Link

  2. #1

    Heat is the deadliest weather hazard in the US, killing an average of 180 people a year over the past 30 years, according to the National Weather Service.

    30-year average, 1996–2025. NWS counts weather-event fatalities, which run well below death-certificate totals.

    National Weather Service (NOAA), 2025Link

  3. 3×

    Large US cities now average six heat waves a year, up from two a year in the 1960s.

    Average across 50 large US metro areas, 2010s and 2020s.

    U.S. Environmental Protection Agency, 2024Link

  4. 436

    436 US workers died from environmental heat exposure on the job between 2011 and 2021, according to the Bureau of Labor Statistics.

    BLS has since recorded 43 such deaths in 2022, 55 in 2023 and 48 in 2024.

    U.S. Bureau of Labor Statistics, 2023Link

Questions people ask

What are the 10 hottest states in the US?

By average summer high (June–August, NOAA 1991–2020 normals): 1. Arizona (93.8°F), 2. Texas (93.8°F), 3. Oklahoma (91.8°F), 4. Louisiana (91.3°F), 5. Florida (91.1°F), 6. Mississippi (90.5°F), 7. Alabama (89.8°F), 8. Georgia (89.8°F), 9. Arkansas (89.7°F), 10. South Carolina (89.7°F).

Which state has the highest heat-related death rate?

Arizona, with 4.5 heat-related deaths per 100,000 residents a year in 2018–2022 (CDC), followed by Nevada (3.8) and Oregon (0.8).

How many heat-related deaths are there in the US?

2,325 people died of heat-related causes in the US in 2023, the most in any year since at least 1999 and more than double the 1999 count. Heat is the deadliest weather hazard in the US, killing an average of 180 people a year over the past 30 years, according to the National Weather Service.

Which state is most at risk from heat?

Arizona ranks #1 of 49 states in Hydrate's Heat & Hydration Risk Index, with a score of 93 out of 100, followed by New Mexico, Arkansas and Mississippi.

Methodology

The Heat & Hydration Risk Index scores each state from 0 to 100 on three pillars. Each is a percentile rank among the states scored (0 for the lowest, 1 for the highest), the approach CDC's Heat & Health Index uses, so one extreme state doesn't flatten the rest:

  • Heat exposure (40%): the state's average summer (June–August) maximum temperature for 1991–2020 (75% of the pillar), plus how far the 2025 summer ran above or below that normal (25%). Source: NOAA NCEI Climate at a Glance.
  • Health burden (40%): heat-related deaths per 100,000 residents a year, 2018–2022, from death certificates. CDC doesn't publish counts under 10; for those states (marked ≤) we use 9, the most the count can be, so their burden is never understated. Source: CDC Environmental Public Health Tracking Network.
  • Vulnerability (20%): share of residents aged 65 and older, who are most at risk from heat and feel thirst less. Source: US Census Bureau ACS 2024 1-year estimates, table B01001.

We'd have preferred heat-related emergency room visits, but only about 30 states report them to CDC, too few to rank every state on equal terms.

Hawaii and the District of Columbia are not covered by NOAA's statewide temperature series, so they are listed but not scored. The index compares states with each other; it is not a forecast of heat illness for any individual. The script that builds the dataset is published with the site's source code, and the raw downloads are kept so every figure can be reproduced.

Cite this report

You're welcome to use any figure or chart on this page. Please credit Hydrate and link back to this page so readers can check the sources.

APA

Hydrate. (2026, October 14). The Hottest States in the US, Ranked by Heat & Hydration Risk. https://hydrateai.app/data/heat-risk-by-state

MLA

"The Hottest States in the US, Ranked by Heat & Hydration Risk." Hydrate, 14 Oct 2026, hydrateai.app/data/heat-risk-by-state.

Link (HTML)

<a href="https://hydrateai.app/data/heat-risk-by-state">The Hottest States in the US, Ranked by Heat & Hydration Risk</a> (Hydrate)

Sources

  1. NOAA National Centers for Environmental Information (2026). Climate at a Glance: Statewide Time Series.
  2. U.S. Census Bureau (2024). American Community Survey 1-Year Estimates, Table B01001 (Sex by Age).
  3. CDC Environmental Public Health Tracking Network (2026). Heat-Related Deaths, 5-year totals by state (measure 1034).
  4. JAMA (2024). Trends of Heat-Related Deaths in the US, 1999–2023 (Howard et al.).
  5. National Weather Service (NOAA) (2025). Weather Related Fatality and Injury Statistics.
  6. U.S. Environmental Protection Agency (2024). Climate Change Indicators: Heat Waves (archived; EPA has since removed the page).
  7. U.S. Bureau of Labor Statistics (2023). 36 work-related deaths due to environmental heat exposure in 2021 (The Economics Daily).

This page summarizes public data for general information. It is not medical advice; talk to a clinician about your own fluid needs, especially if you are pregnant, have kidney or heart conditions, or take medications that affect fluid balance.

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