Graphs for December 2008

I added a ferrite ring to the cable from the Temperature unit to the weatherstation at the beginning of the month but it didn't seem to prevent the error spikes in the readings. On the 13th the weathervane started playing up and only recording values intermittently.On the 17th it stopped sending readings altogether at midnight and it took me until 10am to get it working again. For the 60 missing readings I have manually edited the history file to show 0mph windspeed and a Westerly direction to match the last good reading.

On the 22nd the Weatherstation stopped receiving any data from the sensors. Despite fiddling and eventually replacing the cable between the Temperature unit and the Weatherstation I could not get it to work reliably. The Weatherstation and sensors have always been used as a wired setup, but it can work wirelessly between the Temperature module and the Weatherstation. In the wired setup data is received by the Weatherstation every 8 seconds and the station supplies power to the sensors. If used wirelessly the sensors have to rely on battery power so the transmission period is extended to around 2 minutes between readings to reduce the drain on the batteries.

Having never tried the units wirelessly I did not know if the Weatherstation would receive data but decided to give it a try as the cabled setup was obviously not working properly. I waited what seemed ages after resetting the Weatherstation and telling it to scan for the sensors transmission before it burst into life and showed readings. It's now been about 10 days and as far as I can tell it hasn't missed a reading. It will be interesting to see if the rogue spikes disappear as I'm sure they are generated by the cabling picking up interference. It looks promising as I always had a problem with the minimum Temperature reading being randomly stored at -19.3 but since working wirelessly I haven't had it once. Only time will tell.

A month of 2 distinct halves. The first half wet and windy characterised by sudden drops in pressure. By the 22nd things had calmed down a lot as a large high pressure settled over the UK causing light winds and a blanket of cloud. The cloud clearing on the 26th resulting in dry sunny days and cold nights.


The minimum Temperature this month was -5.2 deg C on the 30th after several clear nights. Maximum temperature of only 10.4 deg C on the 22nd. Towards the end of the month there was a steady drop in temperature but it was to dry and settled for snow. Some areas of the garden were thick with frost which didn't thaw all day as the low sun was masked by trees and mountains.

The minimum temperature in 2008 was this months -5.2 deg C, the maximum temperature was 28.3 deg C in May. In every month except July and August the temperature went below +5 deg C at some time.


A contrasting month with windy days interspersed with the odd still one.The maximum speed recorded in the history file was only 39.5 mph at 1:30pm on the 19th.The strongest gust though was 60.3 mph at 8:46pm on the same day.

With the problems I've had this month with the sensors I decided to refit my old windvane back onto the pole so I could change between them to see if either was working. Unfortunatly the old windvane was not sending any data but I did notice that the new vane with the anemometer cups was much more sensitive to light winds than the old fan type. The cup type has recorded wind speeds as low as 0.6mph whereas the fan type is not rotating at all at that speed.This could just be because the fan type is now 2 years old and has had no additional lubrication since new or it could be that the cup type is slightly more sensitive because it's effective area is larger and it doesn't have to be pointed into wind by the vane to capture any small wind currents.

The maximum recorded gust for 2008 was 65.3mph in March.


Total rainfall of 5.06 inches this month. Most of which fell in only 5 days out of the whole month. There were 16 days when we had no rain at all.

The total rainfall for 2008 was 74.79 inches or 1899mm. The wettest months were January (11.1")and October (12.57"). The driest month was May with only 2.3" of rain.





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© 2007 P.Johnson