Live Weather: How It Works
Current conditions come from a mix of weather stations, radar, satellites and model output. Knowing which parts are measured and which are computed explains why the temperature outside your window sometimes disagrees with the one on your screen.
What the readings mean
| Reading | How it is defined |
|---|---|
| Temperature | Air temperature in shade, about 1.5 m above ground |
| Feels like | Calculated from temperature plus wind or humidity |
| Humidity | Relative — how close the air is to saturation at that temperature |
| Dew point | The temperature at which the air would saturate |
| Pressure | Adjusted to sea level so locations are comparable |
| Wind | Averaged over 10 minutes at 10 m; gusts reported separately |
| Visibility | The furthest distance a dark object is discernible |
Dew point is the better comfort measure
Relative humidity is a ratio, and the same ratio feels completely different at different temperatures — 60% humidity at 15 °C is pleasant, and at 32 °C it is oppressive. Dew point measures the actual moisture content, so it is directly comparable.
| Dew point | Feels |
|---|---|
| Below 10 °C | Dry, comfortable |
| 10–16 °C | Pleasant |
| 16–20 °C | Noticeably humid |
| 20–24 °C | Uncomfortable, sticky |
| Above 24 °C | Oppressive; sweat evaporates poorly |
This is why a 30 °C day in a dry climate is tolerable and a 30 °C day in a humid one is not. High dew point is also what makes heat genuinely dangerous, because the body cools by evaporating sweat and saturated air prevents it.
'Feels like' is two different calculations
In cold conditions it is wind chill, modelling accelerated heat loss from exposed skin. In warm conditions it is the heat index, modelling reduced evaporative cooling in humid air. Both assume an average adult in shade — direct sun can add several degrees to the effective temperature, which neither figure includes.
Why your reading differs from the report
- Station distance. The nearest official station may be at an airport many kilometres away.
- Urban heat island. City centres commonly run 2–5 °C warmer than surrounding countryside, especially at night.
- Microclimate. A sheltered courtyard, a south-facing wall or a valley floor all differ from the regional figure.
- Your own thermometer. A sensor in sunlight or against a warm wall reads high — official readings are taken in ventilated shade.
These are not errors in the report. A regional observation describes a region.
Pressure and what it signals
Reported pressure is adjusted to sea level so that a mountain town and a coastal city can be compared. Standard sea-level pressure is 1013.25 hPa. Falling pressure generally indicates approaching unsettled weather; rising pressure indicates settling conditions. The rate of change matters more than the value — a rapid fall is a stronger signal than a low but steady reading.
Update frequency
Station observations typically update every 10 to 60 minutes, and some app data is model output interpolated between stations rather than a direct measurement. In fast-changing conditions — a passing thunderstorm, a front moving through — radar imagery tells you far more than a numeric reading that may be up to an hour old.