Weather¶

Weather is the meteorological feed for a session. One record is one sample — air temperature, track temperature, wind, humidity, pressure, and a binary rainfall flag — taken roughly every 60 seconds.

Track temperature is its own measurement, separate from air temperature, because the tarmac heats up in the sun and cools at night. It's typically 10–15 °C hotter than the air in dry conditions, which has a much bigger effect on tire behaviour than air temperature alone.

Fields¶

Field	Type	Unit / Range	Meaning
`date`	string	ISO 8601 UTC	Timestamp of this sample.
`session_key`	int	—	The session this record belongs to.
`meeting_key`	int	—	The race weekend.
`air_temperature`	float	°C	Ambient air temperature.
`track_temperature`	float	°C	Track surface temperature.
`humidity`	float	0–100 %	Relative humidity.
`pressure`	float	mbar	Atmospheric pressure.
`wind_speed`	float	m/s	Wind speed.
`wind_direction`	int	0–360 °	Wind bearing. `0` / `360` = North, `90` = East, `180` = South, `270` = West.
`rainfall`	int	0 or 1	Rain indicator — `0` = dry, `1` = wet. Not an amount of rain.

Sample record¶

{
  "air_temperature": 30.5,
  "date": "2023-09-17T13:05:00.000000+00:00",
  "humidity": 78,
  "meeting_key": 1219,
  "pressure": 1008.5,
  "rainfall": 0,
  "session_key": 9165,
  "track_temperature": 36.2,
  "wind_direction": 140,
  "wind_speed": 2.5
}

Rainfall is binary¶

rainfall is 0 or 1 — it tells you whether it is raining, not how hard. There is no public millimetres-per-hour figure. To detect when the rain started or stopped, look for the timestamp where the rainfall flag changes within a session.