Technoline WS 9910 Manual Del Usuario página 26

it does not mean that the product is faulty because it is not raining. It
simply means that the air pressure has dropped and the weather is
expected to get worse but not necessarily rainy.
Note :
After setting up, readings for weather forecasts should be disregarded
for the next 12-24 hours. This will allow sufficient time for the weather
station to collect air pressure data at a constant altitude and therefore
result in a more accurate forecast.
Common to weather forecasting, absolute accuracy cannot be
guaranteed. The weather forecasting feature is estimated to have an
accuracy level of about 75% due to the varying areas the weather
station has been designed for use in. In areas that experience sudden
changes in weather (for example from sunny to rain), the weather
station will be more accurate compared to use in areas where the
weather is stagnant most of the time (for example mostly sunny).
If the weather station is moved to another location significantly higher or
lower than its initial standing point (for example from the ground floor to
the upper floors of a house), remove the batteries and re-insert them
after about 30 seconds. By doing this, the weather station will not
mistake the new location as being a possible change in air-pressure
when really it is due to the slight change of altitude. Again, disregard
weather forecasts for the next 12 to 24 hours as this will allow time for
operation at a constant altitude.
Weather tendency icon
Working together with the weather icons are the weather tendency
indicators (located on the left and right hand side of the weather icons).
When the indicator points upwards, it means that the air-pressure is
increasing and the weather is expected to improve, but when indicator
points downwards, the air-pressure is dropping and the weather is
expected to become worse.
Taking this into account, you will see how the weather has changed and
how it is expected to change. For example, if the indicator is pointing
downwards together with cloud and sun icons, then the last noticeable
change in the weather were when it was sunny (sun icon only).
Therefore, the next change in the weather will be the cloud with rain
icons since the indicator is pointing downwards.
EN9