We all tend to pay a lot of
attention to what the weather is doing, but all too often we
cannot get reasonably reliable data because that information is coming
from maybe 15 or 20 miles away.
Now, Daventry has a privately
run weather station, bringing you real time conditions on your
It is hoped that it will be of use
to you. It is provided free as a Community
Certain terminology may seem difficult to
understand for some of the visitors to this site, so here
are some brief explanations as to what they mean. If there is
something you do not understand, please contact Daventry Weather
and I will endeavour to answer your query.
Basically, it indicates how
good (or bad) a drying day it is. This data is very useful in
agriculture and horticulture. If you compare the total ET for
the month with the total rain for the month, you can get the
deficit in moisture to know when it is necessary to irrigate.
The figure to watch is the final ET reading from the previous
day. All record data resets at midnight.
WM2 or w/m2
Simplistically, if the sky is clear (and it's day time) then the
data reports as 100% sunny from sunrise to sunset. However, when
the Sun rises in the morning and sets at night it is passing
through more of the atmosphere than at midday. W/m2 is a
measurement of the intensity of sunlight hitting the ground, so
the value will be higher at midday when the Sun's intensity is
higher because there is less atmosphere in the way. The W/m2
intensity can also be affected by thin high cloud or haze. You
might still say it was sunny in these conditions, but less of
the Sun's radiation will be reaching you.
being measured are the Watts per square metre where the square
metre is horizontal, ie, flat on the ground. A square metre
ray of energy coming from the Sun will cover approximately one
square metre on the Earth's surface when the sun is directly
overhead. However, early in the morning and in the evening it
hits the ground at an angle and therefore each square metre of
earth will be receiving less energy and the reading will be
Dials & Gauges
If you click once anywhere in the Dials & Gauges area, and then
hover over certain parts of the displayed data text you will see an
explanation which describes how this data is arrived at. Also,
if you click on the words like 'Solar', 'Rainfall', Temperature'
etc, you can access lots of information in graph form.
Please remember that the
information shown on the home page is only updated every five
minutes. Therefore, it may say it is dry when it has been
raining for a few minutes. Dials & Gauges will give a more up to
date view of current weather conditions because it is usually
only 5 - 8 seconds behind real time.
Also, please remember that
it may be dry where the weather station is situated, even though
you may be having a downpour! Finally, the
Rain Days This Month shown on
Rainfall Data will not include any
amounts less than 0.5mm because they are insignificant.
Snow and after
When there has been a fall of snow it sometimes takes a while to
melt away. When this is happening it can cause inaccurate
information to appear on the website as the melting snow 'drips'
into the rain catcher. It gives the equipment the sense that it
is or has been (a) raining or (b) snowing/sleeting (according to the outside
temperature). Please make allowances for these anomalies which
are quite beyond mine or the equipment's control. Also, when
there has been a sharp frost and water falls into the rain
catcher as the temperature rises, it can cause inaccurate
information such as "Snowing/Sleet Fall' to appear when there is
a clear blue sky. This is caused by the 'dripping' water and the
current low temperature, and the workings of the weather station
regards these two conditions as being compatible with either
snow or sleet.
Each first of the month the data
updates at 09:15, and before then the hours for the month relate
to the previous month.
* Recorded sunshine is just that, recorded by a
solar sensor some 12' off the ground. It is not possible to
record every single minute of sunshine because the Sun's rays
have to strike the sensor, and with natural obstacles like
Borough Hill blocking the Sun, and the need for the Sun to be
high enough to strike the sensor, it may be up to 30 minutes
after sunrise that the sunshine actually starts to be recorded.
Furthermore, reports could say 'cloudy' when the sky is clear.
For a report to say 'sunny', the software needs a reading of
around 70%, but as the Sun starts to set in a clear blue sky,
the reading drops below that amount, resulting in a