Heat Safety Calculator高温与中暑评估器
NWS heat index plus a decision tree for cramps, exhaustion and heat stroke — with aggressive cooling steps. NWS 热指数公式，加热痉挛、热衰竭与热射病的鉴别决策树和强力降温步骤。
How the heat index works
Humans cool mainly by evaporation. Sweat is only useful when it turns to vapor, so humid air that is already nearly saturated makes a moderately hot day dangerous. The heat index — also called apparent temperature — combines air temperature in Fahrenheit with relative humidity to estimate how hot a healthy adult actually feels in shaded, light-wind conditions.
This calculator implements the U.S. National Weather Service Rothfusz regression, a nine-term polynomial fitted to physiological data, together with its two published corrections: in very dry air below 13% humidity and 80–112 °F the index is reduced, and in hot, muggy air above 85% humidity and 80–87 °F it is increased. When the preliminary estimate falls below 80 °F, the simpler Steadman-style average is used instead, which is why dry desert heat can read cooler than the thermometer while muggy eastern-trail heat reads far hotter. A standard check value: 90 °F at 60% relative humidity returns about 100 °F.
Sun, exertion and the missing variables
The official index assumes shade. Direct sun, heavy exertion and lack of wind can add up to roughly 15 °F to apparent heat, so the tool flags that as a planning upgrade rather than pretending to compute a precise adjustment. The NWS bands run from caution at 80–89 °F through extreme caution at 90–103 °F, danger at 103–124 °F and extreme danger at 125 °F or higher.
Cramps, exhaustion, stroke — the decision tree
The three heat illnesses form a progression, but heat stroke can appear without warning. Cramps in the legs or abdomen mean stop, shade, electrolytes and gentle stretching. Heat exhaustion shows as heavy sweat, nausea, weakness, headache and a fast weak pulse — lie down, shed layers, and cool with wet towels at the neck, armpits and groin plus fanning. Heat stroke is a neurological emergency: hot skin, confusion, odd behavior, collapse or seizures, sometimes after sweating stops. Call emergency services immediately and cool first — ice-water immersion is the gold standard. Never force fluids into someone confused or unconscious, never leave children, older adults or dogs in parked cars, and remember that full heat acclimatization takes the body 7–14 days of graded exposure.
热指数是怎么算的
人体主要靠蒸发散热。汗液只有蒸发成水汽才有用，因此接近饱和的潮湿空气会让一个并不算极热的日子变得危险。热指数（也称体感温度）把华氏气温与相对湿度结合，估算健康成年人在遮阴、微风条件下实际感受到的温度。
本计算器实现美国国家气象局（NWS）的 Rothfusz 九项回归多项式，并包含官方公布的两项修正：湿度低于 13%、气温 80–112 °F 的干热环境下调；湿度高于 85%、气温 80–87 °F 的闷热环境上调。当初步估算低于 80 °F 时改用更简单的 Steadman 平均值——这解释了为什么干燥的沙漠热可能比温度计显示的更“好受”，而潮湿闷热的环境会远比温度计更危险。标准校验值：90 °F、相对湿度 60% 时热指数约为 100 °F。
日晒、运动与公式之外的变量
官方指数假设在阴凉处。直晒、重体力活动与无风最多可使体感再升高约 15 °F，因此工具以风险提示的形式上调一档，而不是假装有精确公式。NWS 分级为：80–89 °F 谨慎、90–103 °F 高度警惕、103–124 °F 危险、125 °F 及以上极度危险。
痉挛、衰竭、射病——决策树
三种热病通常递进，但热射病也可能毫无预兆地出现。腿部或腹部痉挛意味着停止运动、到阴凉处、补电解质并轻柔拉伸。热衰竭表现为大汗、恶心、虚弱、头痛、脉搏快而弱——平躺、脱衣，在颈部、腋下、腹股沟敷湿毛巾并扇风。热射病是神经系统急症：皮肤发烫、意识混乱、行为异常、虚脱或抽搐，且可能发生在停汗之后。立即呼叫急救，先降温——冰水浸泡是金标准。绝不要给意识混乱或昏迷者强行灌水；绝不要把儿童、老人或狗留在停放的车内；身体完全适应高温需要 7–14 天的逐步暴露。