Rainfall averages used to calculate the ‘Dep. from norm’ (departure from normal) are the 1981-2010 averages for Sidmouth, the nearest official station to this site. Although the average here appears to be slightly higher so far, this is in part due to several wet years recently.
Temperature averages used to calculate anomalies are estimated 1981-2010 values for this site, obtained using nearby official station averages, and also by comparing recent monthly averages from these stations to this site to calculate the difference.
These estimates take account of how the weather station records an average of all readings rather than the max+min/2 method and 0900-0900 GMT observing period for Met Office sites, and also local climate factors such as cool nights due to being in the Otter Valley, which can act as a frost hollow compared to surrounding higher ground and coasts.
Some ‘days of rain over .2mm’ may be be due to dew or frost melt, and as such a very small percentage of total rainfall is from this source.