Heatwaves: why it feels worse every year

The short version

Every summer, the same line returns: “we’ve never seen this.” Sometimes that is true in a local weather sense. Sometimes it is mostly a feeling shaped by urban heat, alerts, social feeds, and comparisons to cooler childhood summers. Both can be true at once.

Climate science is fairly clear on the core — warming raises the frequency and intensity of many heat extremes — and fairly careful on the details: every wave is not “the worst in history,” and one summer is not a trend. This piece separates signal, noise, and summer psychology.

What climate science does (and does not) say

IPCC reports have established for years that human-caused warming alters extreme-event regimes. For heat, the central message is robust: in many regions, hot spells have become more frequent, longer, and/or more intense than in the pre-industrial era, with risk rising further if warming continues.

What that does not imply:

• that your city breaks a record every year;
• that 2026 is necessarily “worse” than 2025 everywhere;
• that one stifling afternoon can be pinned on a single factor without analysis.

Event attribution (work in the spirit of World Weather Attribution and related studies) tends toward formulations like: this event became X times more likely / Y degrees hotter in today’s climate than in a climate without human forcing (that is, without human influence on climate via emissions). That is not sensationalism; it is extremes statistics, with uncertainties stated.

Why “worse every year” feels so convincing

1. The baseline moved

Even a “normal” year today plays out on a warmer planet. Records fall more often because the temperature distribution shifted. That is not an illusion: it is the simplest mechanism, documented in global assessments (NOAA, Copernicus, and others).

2. Cities amplify the sensation

The urban heat island (concrete, asphalt, fewer trees, waste heat) can keep evening temperatures high in city centers while nearby countryside cools. Most people live in dense urban areas. You are not comparing summer to an ideal weather station; you are comparing it to a top-floor flat.

3. Humidity, nights, and human bodies

A “worse” heatwave is not only the 3 p.m. peak. It is often:

• tropical nights (nights when the minimum stays ≥ 20°C) that block recovery;
• humidity that impairs sweating;
• duration (4 days vs 10 days);
• vulnerable groups (older adults, isolated people, outdoor workers).

Two summers with the same official maximum can therefore feel very different.

4. Media and social memory

Weather alerts, red maps, “42°C in my car” clips, looping news: all of it concentrates attention. We remember recent extremes better than average summers. We also under-weight variability: a slightly less extreme summer after two brutal ones can feel “normal,” while still being hot relative to the 20th century.

5. We compare to childhood, not climatology

“We never had this before” mixes a real climate signal with selective nostalgia. Heatwaves existed. In many regions they were on average less frequent / less intense — but childhood is not a homogeneous archive.

El Niño / La Niña: useful context, not an excuse

ENSO (El Niño–Southern Oscillation) is the big climate yo-yo in the tropical Pacific: warm phases (El Niño), cooler phases (La Niña), and neutral phases in between. It can nudge a given year’s global temperature up or down a bit — and sometimes influence weather farther away — without canceling long-term warming. (Dedicated decode: what is El Niño?.)

For Western Europe, the “Pacific phase → heatwave here” link is often less direct than for other regions. In other words:

• yes, ocean context matters for the global year and some weather patterns;
• no, “it’s El Niño” alone does not explain a Paris or Lyon heatwave;
• no, “it’s just natural variability” does not erase the shifted baseline.

The right use here: context, not verdict.

“Worse” by which metric?

Depending on what you track, rankings change. Here are the most-cited measures — and their traps:

A year can smash afternoon records without being the deadliest — and the reverse, if nights stay hot and services are strained.

What we can / cannot say

How to read the next summer headlines

1. Look for duration and nights, not only the afternoon record.
2. Separate local record from regional/global trend.
3. Distrust maps with no scale or reference period.
4. When a piece mentions attribution (“X times more likely”), check whether it cites a study — and the uncertainty.
5. For the big picture, prefer IPCC syntheses and climate services (NOAA, Copernicus) over viral posts alone.

Practically, during a heatwave

Without turning this into medical advice:

• hydrate, use the coolest rooms, cut effort in peak hours;
• check on isolated older people;
• do not confuse “I can cope” with “my neighbor can cope.”

Climate decoding does not replace health common sense; it explains why alerts return more often.

Two honest ways the feeling can be “right” and “wrong” at once

Right: your body is reacting to hotter nights, denser cities, longer spells, and a warmer baseline. The discomfort is not imaginary, and population-level risk has shifted in many places.

Wrong (or incomplete): “this Tuesday proves the whole climate story by itself,” or “because last year felt worse in my street, the global trend must have jumped again.” Local weather remains noisy. Trends show up more cleanly in multi-year, multi-region statistics than in any single heat dome you remember from a news cycle.

Holding both ideas at once is the adult version of summer literacy: take the risk seriously, refuse the cartoon explanation.

Adaptation is part of the story — not a denial of warming

Air conditioning, heat-health warning systems, cooler building design, shaded streets, and workplace rules for outdoor labor can reduce deaths and hospital strain even while extremes become more common. That is not an argument that warming is fake. It is an argument that impacts are mediated by society, not only by the thermometer.

When headlines say a heatwave is “historic,” ask two follow-ups: historic for which metric, and how prepared was the place that lived through it?

Going further

• IPCC AR6 — reference synthesis on climate and extremes.
• IPCC WG1 — The Physical Science Basis — physical basis, extremes chapters.
• Climate.gov (NOAA) — accessible climate explainers and monitoring.
• NOAA NCEI monthly reports — observed temperature updates.
• Copernicus C3S — European/global climate monitoring.
• World Weather Attribution — extreme-event attribution analyses.