 Along with the rest of South West England , Exmoor has a temperate climate which is generally wetter and milder than the rest of England . The mean annual temperature at Simonsbath is 8 @.@ 3 ° C ( 46 @.@ 9 ° F ) with a seasonal and diurnal variation , but due to the modifying effect of the sea the range is less than in most other parts of the UK . January is the coldest month , with mean minimum temperatures between 1 and 2 ° C ( 34 and 36 ° F ) . July and August are the warmest months in the region , with mean daily maxima around 21 ° C ( 70 ° F ) . In general , December is the month with the least sunshine and June the month with the most sun . The south west of England has a favoured location with regard to the Azores high pressure when it extends its influence north @-@ eastwards towards the UK , particularly in summer . 
