The damp weather seems to have receded – dust off those lenses, remove the fingerprints & buy a polarising filter. It will not only make your blue skies bluer – yes bluer & cut unwanted reflections in glass & water. It will  also protect your lens. If you’re interested in introducing creative blur into your images then it’ll also cut the amount of light entering your camera – letting you make longer exposures. Easy. If I had one filter in my bag in the summer it would be a polariser.