Archived weather data

The full data set back to November 2005, with readings every 10 minutes, is archived on-line at Weather Underground. When using these data please note the following caveats:

The weather station is in a mature garden with large trees nearby and the wind instruments are only at a height of three meters rather than the standard 10 meters. As a result windspeeds will be lower than reported by official weather stations, and the precise wind directions may be impeded slightly by the trees.
Occasionally there have been weather instrument failures, which mean that the online data during those periods may not be accurate. For wind data it means that no wind was recorded and the online data will show 0 windspeed and the same direction during the failure period. For rain it means either that some rain may not have been recorded or, more commonly, that several hours of rain might suddenly appear within a single 10 minute period.
The months affected are:
- Wind
  - Feb-Mar 2007
  - Mar 2008
  - May 2009
  - 12-26 Feb 2014 -wind vane broken so wind direction not recorded & station lower than usual, so the speed was lower.
  - 30 March – 1 April 2017 – the anemometer had stopped working, so wind speed was not being reported.
- Rain
  - Oct 2006
  - Oct 2007
  - Jan 2008
  - Jan 2009
  - Dec 2009
  - Jun 2011
  - Jan 2012
  - July 2012
  - May 2024 – Station stopped recording rainfall after 30 April, but suddenly at midnight 10 May it recorded 89.4mm of rain at one time. Comparing to the nearest Weather Underground station at Llangefni, it appears to have missed rain on 1, 4, 7, 13 and 14 May (about 18mm total). On 14 May I cleaned out rain gauge and ran about 0.6mm of water through it (after a morning of rain) and it then started registering. The next rain on 16 May started to be recorded properly.
  - 3 Sept 2024 – 27 Jan 2025 – The old Davis Vantage Vue weather station was replaced by a Weatherflow Tempest one. This uses a haptic sensor to detect rain, rather than a tipping bucket as used in the old stations. This detects rain by vibrations of raindrops landing on the top of the sensor. This has advantages, but a big disadvantage is that it seems to over-record rain when it is windy. Comparisons with the old Davis station (which was run alongside the new one for six weeks) and with a manual funnel rain gauge, show the Tempest quite often recorded 1.5 to 2 times as much rain, even more during very windy weather, although other times it was less. A new Davis Vantage Vue was installed on 27 Jan 2025 at noon. Any rainfall data recorded on the Weather Underground site during this period should be suspect. Note that the monthly rainfall tables that I maintain on the current site have been modified for Oct 2024 – Jan 2025 to reflect the rainfall from a nearby weather station at Moelfre to avoid having wildly inaccurate figures in it.
    Comparisons were also made between the Davis and Tempest stations for temperature and barometric pressure, and they were both very similar. Wind wasn’t compared because the two stations, although sited near each other, were at different levels, so would naturally have different wind speeds.
- Air Pressure
  - November 2020 – Station was recording pressure much lower (15-19 mb) than actual pressure from 1-5 November.
- All Data
  - 1 Oct (ca 10:15) – 3 Oct (ca 15:00) 2025 – Data communication locked up on the computer running the weather station software, so no data was recorded or uploaded.
Up until 1 August 2012 (07:00am BST) the weather station in use was a Oregon Scientific WMR 928. Then a Davis Vantage Vue was being used until 3 September 2024. The two stations were run together for a while to compare their results, and there were slight differences (with the Davis station probably being more accurate). When compared to the old OS station, the Davis station had:
- average daily temperature about 0.5ºC lower and high temperature about 0.5° higher (the old temperature sensor was in a more sheltered place, thus less accurate)
- average daily wind speed about 0.12 mph lower and high wind speed about 2.4 mph higher (the old anemometer doesn’t seem to spin as easily and smoothly as the new one).
- same dominant wind direction to the nearest 8-point compass direction
- daily rainfall about 10% lower. Note that the readings from the Davis station are closer to those from a manual rain gauge than were the OS station readings.

Note: To get the historical data go to our page on the Weather Underground, scroll down to the “Weather History” section, and use the tabs and date specification boxes to get the required data in the table at the bottom.