U.S. Warming by State: What the New Study Shows

Short answer: what the new study found (and why it matters)

Most states are warming, but not always in the average. A new PLOS Climate analysis finds 41 U.S. states show warming in at least one part of their temperature range since the mid-1900s, even though only 27 states show a clear rise in mean temperature.
Where the warming shows up differs by region. In much of the West, the hottest days are rising faster (higher annual maximums). In parts of the North/Central U.S., the cold end is rising faster (warmer nights, milder winters).
“Warming dominance” leaders include Rhode Island, Arizona, Connecticut, Massachusetts, and California.
A “warming hole” still appears in parts of the South/Central U.S. Several states show no statistically significant warming signal across tested temperature levels in this method (commonly listed: Alabama, Arkansas, Illinois, Kansas, Mississippi, Missouri, Oklahoma, Texas; some coverage also includes Georgia).
Big takeaway for planning: If your state’s averages look “flat,” you may still be getting riskier extremes (hotter highs or warmer lows). That can change heat planning, crop timing, pests, and infrastructure stress.

State quick-scan: what kind of warming is showing up?

Use this as a fast lookup, then jump to the sections below for what to do with it. The categories describe where warming is most detectable across the temperature range.

Pattern (plain language)	What’s changing	States often highlighted in coverage	What you’ll feel locally
Hot-end warming (highs rising faster)	Annual maximum temperatures climb faster than the lows	Many West Coast/West states such as CA, OR, WA, NV (also ID, WY noted)	More intense hot spells; higher heatwave risk; greater temperature dispersion
Cold-end warming (lows rising faster)	Minimum temperatures rise faster than maximums	Northern/Central examples include the Dakotas and Minnesota (plus IA, NE, MT noted)	“Softening” winters; fewer deep-freeze nights; warmer nights with less cooling
Broad shift (range rises together)	Both highs and lows increase at a similar pace	Portions of the Upper Midwest, Northeast, and Northwest	Warming is noticeable across seasons, not just at one extreme
Warming hole (no clear signal in this test)	No statistically significant trend detected across tested temperature levels	AL, AR, IL, KS, MS, MO, OK, TX (some lists also include GA)	Climate change can still be present, but it’s harder to detect in statewide aggregated statistics

Takeaway: “US warming by state” is no longer only “who warmed most on average?” It’s also which slice of the temperature range is shifting where you live.

What does “warming dominance” mean?

The study introduces warming dominance as a way to rank where warming is most consistently stronger across the temperature distribution. Put simply: when multiple points in the temperature range are tested (not just the average), some states show a stronger, more repeatable warming signal.

States described as warming “leaders” with strong dominance include Rhode Island, Arizona, Connecticut, Massachusetts, and California. Takeaway: Dominance describes how robust and prominent warming is across the distribution, not just a single mean trend.

Why averages can miss warming (the “chicken” problem)

The researchers use a simple riddle: two hungry people share one chicken; one eats it all, the other gets none. On average, each ate “half a chicken,” but that average hides the real outcome.

Climate can work similarly. A state’s average annual temperature can look stable even while the hottest days are getting hotter or the coldest nights are getting much warmer. That’s why the study emphasizes quantiles (points along the distribution) rather than only the mean.

Takeaway: If your state is “not warming on average,” it may still be warming in the tails (extremes) rather than in the middle.

Three warming patterns you can actually feel on the ground

1) Lows rising faster: warmer nights, milder winters

Where minimum temperatures rise faster than maximums, winter nights soften and the cold end of the year shifts upward. That can mean less reliable snow and ice conditions and changes in pest survival and timing.

Soil-based insight: As freeze-thaw patterns change, soils can cycle differently between frozen and wet states. That can affect spring field access, compaction risk, and nutrient movement with meltwater and early rains.

Takeaway: Cold-end warming changes timing, pests, and the soil-water calendar.

2) Highs rising faster: hotter extremes and higher heatwave risk

In much of the West, warming shows up strongly on the hot end: highest annual temperatures rise faster than lows. That can increase temperature dispersion and raise the odds of dangerous heat days, especially when soils are dry and plants shut down.

Farmer perspective: When highs spike, the practical question is how often crops stop photosynthesizing and whether nights cool enough for recovery. Heat stress is an event problem, not a mean problem.

Takeaway: Hot-end warming concentrates risk into short windows that can make or break yields, livestock health, and worker safety.

3) Broad shift: everything warmer, season after season

Some regions show more uniform warming across the range, meaning both cool and warm parts of the year rise together. This can make warming easier to perceive because it shows up across seasons, not only as extreme outliers.

Takeaway: Broad shifts simplify the message (“it’s warmer overall”) but still require specific responses for heat, flooding, and ecosystems.

Which states are warming fastest? Reconciling “dominance” vs. average-warming rankings

Different sources answer different questions, so rankings can look inconsistent. One list may emphasize distribution-wide dominance, while another emphasizes average temperature change since a baseline year.

This study’s “leaders” (warming dominance): Rhode Island, Arizona, Connecticut, Massachusetts, California are highlighted for especially strong, dominant warming patterns across the temperature distribution.
Climate Central’s “fastest-warming states” (average annual temperature change since ~1970): lists often include Alaska near the top (often reported around +4.3°F since 1970), plus states such as Delaware, Massachusetts, New Jersey, New Mexico, Vermont depending on method and year.

Both can be true because they measure different things: average change since a baseline year vs. where in the temperature distribution warming is most detectable. Takeaway: When comparing rankings, confirm whether they describe means or distribution-wide changes.

The “warming hole”: which states, and why it’s complicated

Some analyses highlight an anomalous region where statewide aggregated data shows little to no statistically significant warming signal in this particular test. Commonly cited warming-hole states include Texas, Oklahoma, Mississippi, Alabama, Kansas, Arkansas (sometimes Georgia), while other coverage lists Alabama, Arkansas, Illinois, Kansas, Mississippi, Missouri, Oklahoma, Texas.

Researchers and NOAA explanations have suggested contributors such as aerosols, land use change, and water-cycle shifts that can mask or offset warming at regional scales. This does not imply impacts are absent.

“Not statistically significant” is not the same as “no change.” It can mean the signal is harder to detect given the method, timeframe, and variability.
Statewide averages can hide local changes. Subregions or specific extremes may still be shifting in ways that affect people and farms.

Takeaway: Treat the warming hole as a planning challenge, not as a reason to ignore risk.

What these patterns mean for health, agriculture, and infrastructure

Public health and heat risk

Warmer nights can increase health stress because bodies and buildings do not cool as well. Overnight heat risk can rise even if daytime highs do not set records.
Hot-end warming increases the likelihood of extreme heat days and heatwaves. This can strain outdoor workers, increase emergency visits, and compound wildfire-smoke exposure in the West.

Takeaway: Heat planning should track nighttime minimums and upper-end extremes, not just average summer temperature.

Agriculture and food systems

Cold-end warming can shift chill hours, pest overwintering, and planting windows. It can also change spring soil trafficability (freeze-thaw, mud, compaction risk).
Hot-end warming can push crops and livestock over stress thresholds even if annual means change slowly. Irrigation demand and timing become sharper.
Uniform warming can lengthen growing seasons in some places while increasing evapotranspiration, drought stress, and disease pressure.

Takeaway: Distribution shifts translate into management shifts: planting dates, varieties, shade and water for livestock, and soil-cover strategies.

Infrastructure and budgets

Winter softening can change road maintenance needs through freeze-thaw damage and shifting de-icing patterns, even if it feels less cold.
Hotter highs stress power grids, asphalt, rail, and water systems. Peak cooling demand often matters more than annual averages.

Takeaway: Budgeting should follow the extremes you pay for (peak heat, freeze-thaw), not just the mean temperature.

What to do next: a practical checklist (residents, planners, and farms)

If you’re a resident or homeowner

Check your state’s extremes, not just the mean. Look for trends in summer maximums and nighttime minimums.
Prepare for the specific risk: If highs are rising, prioritize cooling, shade, and heat plans. If lows are rising, watch pests, allergens, and winter infrastructure issues.

If you’re a farmer or land steward

Track soil moisture and soil cover through heat spells. Bare soil heats and dries quickly and can amplify field-level heat stress.
Adjust for new shoulder seasons. Warmer early spring can tempt earlier fieldwork; protect soil structure by avoiding compaction when soils are saturated.
Tangible decision you can try this week: Choose one meal built around beans or lentils (plus seasonal vegetables) instead of beef to reduce food-related emissions.

If you work in local government, schools, or public health

Update heat protocols to include overnight lows (cooling centers, extended hours, worker protections).
Plan around extremes: peak-load energy planning, tree canopy investments, and heat-resilient surfaces where appropriate.
Communicate locally: Use the “which slice is warming?” framing to explain why residents may experience change differently across places.

Takeaway: Actions should match whether your area is shifting at the hot end, cold end, or across the whole range.

How to verify temperature trends for your state (in 10 minutes)

To move from headlines to local decisions, pair distribution-based insights with public climate tools. Comparing annual means with seasonal and extremes indicators can reveal what is changing most in your area.

Use NOAA Climate at a Glance for temperature trend charts (state or climate division).
Compare annual average trends with seasonal trends (winter vs. summer).
If available, check indicators that reflect extremes (heatwave days, very warm nights, very cold nights) in state climate summaries or extension resources.

Quick workflow:
1) Search: NOAA Climate at a Glance [Your State] temperature
2) Note the trend line and baseline years
3) Repeat for winter vs summer (seasonal)
4) Add an extremes indicator (warm nights / hot days) if your state summary provides it
5) Align your actions to the extreme that is moving

Takeaway: Use local trend tools to translate “US warming by state” into decisions that fit your place.

Sources (and what each one contributes)

PLOS Climate (2026): distribution-based analysis of regional heterogeneity and “warming dominance” across U.S. states (Alaska and Hawaii not included in the study).
Climate Central: average-warming rankings since 1970 and city-level comparisons for mean-change questions.
NOAA / EPA state summaries: place-based context for impacts (heat, flooding, drought, agriculture) and practical trend verification.