Heatwaves in coastal cities: the night that does not cool down

Two in the morning, a second‑floor apartment in Bat Yam. The window is open, the fan turns and incoming air is as warm as midday. The evening forecast promised "slight relief in temperatures." The app says it is relatively pleasant outside. Why is the bedroom unbearable?

Israel's coastal cities enjoy an advantage envied inland: the sea breeze. It arrives in the afternoon, cools the street and reminds everyone why they wanted to live near the sea. Until a heatwave makes it disappear. Apartments in older buildings, with a west‑facing wall and a single window, then remain hot after forecasts already announce relief. Sleep breaks down first among older people and babies. This is not a comfort question. It is an environmental and health issue.

Your room is not at the weather station

One detail explains the gap: the measuring station supplying the forecast usually stands in an open area, park or field. It does not measure the crowded street, certainly not a second‑floor bedroom without shutters, with a wall absorbing sunshine all afternoon.

The city itself produces heat. Asphalt and concrete absorb it by day and release it at night. Air conditioners expel warm air into the street. Few trees and little shade leave nothing to cool it. Researchers call this an "urban heat island." You call it a sleepless night. The difference explains why the forecast said "it wasn't that bad" while bed felt very bad indeed.

The window mistake almost everyone makes

Most people open windows when it is hot. Sounds logical? But when outside air is warmer than indoor air, opening a window only brings in more heat. The rule is simple: ventilate when there is a breeze and it is cooler outside, usually before dawn. Close windows, shutters and curtains during sunny hours.

The difference between an exterior shutter and an indoor curtain is larger than it seems. A shutter blocks sunlight before it reaches the glass. A curtain blocks it after the heat is already inside.

What can be done this week

Not everyone can reinsulate an apartment. Full insulation means thousands of shekels, builders and disruption. But small actions make a large difference. Sealing gaps around an old air conditioner, for example, is an afternoon's work that prevents cool air escaping.

What about the air conditioner itself? A fan alongside an air conditioner at a reasonable temperature distributes coolness better, avoiding an excessively low setting and saving electricity. In an apartment building, a light‑colored roof reflecting sunlight rather than absorbing it can lower temperatures on upper floors. But that requires a committee decision, not one resident's.

Who is at risk, and what to do

A heatwave does not affect everyone equally. A resident without working air conditioning. Someone on the top floor directly beneath the roof. Older people who do not always feel thirsty. People taking medication that interferes with temperature regulation. All face higher risk.

Have an older neighbor living alone? Knocking during a heatwave is more than politeness. It could save them. Calling the health fund or municipal hotline during a heatwave is not excessive drama. They are points of contact. Yes, drinking water matters greatly to the body. But it does not cool the apartment.

What the municipality can do by next season

Major solutions take time. A tree planted today will cast substantial shade only in several years. But a municipality can change some things within one season: shade along the walk to the bus stop, longer opening hours for an air‑conditioned library or community center where people can sit during the hottest hours, and a plain‑Hebrew alert explaining what to do rather than merely announcing heat.

A shelter at a bus stop sounds like a small detail, but it works by the coming summer. On the next hot night, when the breeze disappears again, the difference between a prepared city and an unprepared one will be felt in every bedroom.