Live heat risk · Kuwait City
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This tool computes the apparent temperature — the heat index — from live temperature and humidity, using the same equation that runs inside the Saya wearable. It then shows the risk hour by hour, with Kuwait's legal midday work-ban window marked, so you can see whether the danger actually falls inside the protected hours.
Each bar is the heat index for that hour. Bars outlined in black fall inside the 11:00–16:00 work ban (1 June – 31 August). Bars outside that outline are hours when outdoor work is legally permitted — whatever the heat index says.
The hottest hour is often not the most dangerous one. Heat index combines temperature and humidity, because what harms the body is not air temperature — it is the body's inability to shed heat. Sweat cools you only when it evaporates, and evaporation slows as the air gets more humid.
In Kuwait that produces a counter-intuitive pattern. Mid-afternoon is the hottest and driest part of the day, so sweat evaporates efficiently and the heat index can sit below the air temperature. Later in the day the temperature falls but humidity climbs, evaporation becomes less effective, and the heat index can rise even as the thermometer drops. This is precisely why a clock-based rule is a poor proxy for physiological danger — and it is the question the Saya field study is designed to answer.
One limitation worth stating plainly. These figures are shade values from a weather station. A worker in direct sun on a reflective surface experiences a substantially higher effective heat load — solar radiation and radiant heat from concrete and steel are not captured here. The occupational standard for this is WBGT (wet-bulb globe temperature), which adds a radiant-heat measurement. So treat this page as a conservative floor on outdoor risk, not a ceiling.
Thresholds follow the US National Weather Service heat-index categories, converted to Celsius. Saya uses the 32 °C and 41 °C boundaries as its warning and danger conditions.
The heat index is the Rothfusz (1990) regression used by the US National Weather Service. It is defined in Fahrenheit, so temperature is converted, the equation applied, and the result converted back to Celsius:
Two NWS adjustments are applied at the edges of the range. In dry heat (R below 13%, T between 80 °F and 112 °F) the index is reduced, which matters in Kuwait where summer humidity is often very low. In humid, milder conditions (R above 85%, T between 80 °F and 87 °F) it is increased. Below roughly 80 °F a simplified formula is used instead, as the regression is not valid there.
Why this matters for the research: heat index combines temperature and humidity into a single measure of physiological strain, because sweat cannot evaporate efficiently in humid air. A 42 °C day at 15% humidity and a 38 °C day at 50% humidity are not equally dangerous, and air temperature alone cannot tell them apart.