 Along with the rest of South West England , Plymouth has a temperate oceanic climate ( Köppen Cfb ) which is generally wetter and milder than the rest of England . This means a wide range of exotic plants can be grown . The annual mean temperature is approximately 11 ° C ( 52 ° F ) . Due to the modifying effect of the sea the seasonal range is less than in most other parts of the UK . As a result of this summer highs are lower than its southerly latitude should warrant , but as a contrast the coldest month of February has mean minimum temperatures as mild as between 3 and 4 ° C ( 37 and 39 ° F ) . Snow is rare , not usually equating to more than a few flakes , but there have been exclusions , namely the European winter storms of 2009 @-@ 10 which , in early January , covered Plymouth in at least 1 inch ( 2 @.@ 5 cm ) of snow ; more on higher ground . Another period of notable snow occurred from 17 – 19 December 2010 when up to 8 inches ( 20 cm ) of snow fell through the period – though only 2 inches ( 5 @.@ 1 cm ) would lie at any one time due to melt . Over the 1961 – 1990 period , annual snowfall accumulation averaged less than 7 cm ( 3 in ) per year . July and August are the warmest months with mean daily maxima over 19 ° C ( 66 ° F ) . 
