Website
The IPL Weather Station website displays various
different weather-related measurements and statistics compiled over different
periods. The Latest Readings page displays the most recent data
extracted from the Weather Station. It also has a photo of the current scene
outside (taken by a webcam) and a map indicating the camera's position and the
current wind speed and direction. The Weekly Graphs page has two graphs
that can show how temperature, barometric pressure, humidity and rain rate have
changed over the past 7 days. Maxima, minima and means for these measurements
over different periods are displayed in tables in the Daily Stats, Monthly
Stats and Yearly Stats pages. In addition, there is a page to
display the highest and lowest measurements ever recorded and a page of
astronomical data such as sunlight times and the current moon phase.
Location / Data Accuracy
The IPL Weather Station is a wireless Davis Vantage Pro
model. It is fixed on the roof of our main offices, located in Grove Street in
the centre of Bath (see the map on the Latest Readings page).
Temperature readings may be affected by heat from the surrounding buildings and
vehicles, as well as the absorption and reflection of heat from the roof. Wind
readings may be subject to some shielding and disturbance from surrounding
buildings despite the anemometer being mounted on a 4-metre pole to raise it to
a height above our chimneys.
Weather Forecast
The banner at the top of the Current Data page includes
a brief short-term forecast. It is based on a method introduced in 1860 by
Admiral Robert Fitzroy. The forecast is produced from a combination of the time
of year and barometric activity in the last 6 hours. For example if it is
winter*, the temperature is low enough for possible snow**,
the barometric pressure is low*** and has been falling rapidly****,
the forecast will be "Severe storm, gales, rain or snow".
* The year is divided into a warmer and a colder half
for this forecast. The colder half begins at the Autumn Equinox (22nd
September) and ends at the Spring Equinox (21st March).
Data Update Frequencies
The frequencies at which wind readings (speed
and direction), non-wind readings (temperature, barometric pressure etc.) and
the webcam photo updates are made are all different. This reflects the
different variability of these three types of data. Here are the current
rates:
| |
|
Data Type
|
Update Frequency
|
|
Wind Readings
|
Every 2 seconds
|
|
Non-Wind Readings
|
Every 15 minutes
|
|
Webcam Photo Updates
|
Every 30 seconds
|
|
** Below 4 degrees Celsius
*** Below 982 millibars
**** A drop of at least 2 millibars in the 6-hour
period
|