Tukuk-OSTemperature on a forecast is standardized: a thermometer in a louvered box, about two metres above grass, in the shade, with air flowing — not what your asphalt car park experiences. Humidity is almost always relative humidity: the share of water the air could hold at that temperature, already full, out of its maximum. So 50% at 30 °C carries far more actual water than 80% at 10 °C — “humid” is a feeling, not a number, and the number that tracks the feeling is the dew point: above roughly 20 °C dew point, sweat stops doing its cooling job.
Pressure is forecast gold because air flows from high to low and the trend predicts the next day: a slowly falling barometer usually means a warm, moist low approaching — often 12 to 24 hours ahead of rain. Rising pressure generally means clearing and drying. A “front” is just the boundary between two air masses; cold fronts ride under warm air and force it up fast, giving short hard showers, while warm fronts slide gently over, giving long steady rain and drizzle.
Forecast “probability of rain” (PoP) is commonly misunderstood even by weather services’ own surveys: it means the chance that at least a measurable amount falls at your point, whatever the amount. A 30% PoP can still mean a flood down the road; a 90% PoP can mean 15 minutes of drizzle. For the size of the event you need the quantitative forecast, not the percentage.