Sentence:  The day was <WSD>cool</WSD> and snappy for August, and the Rise all green with a lavish nature. Now we plunged into a deep shade with the boughs lacing each other overhead, and crossed dainty, rustic bridges over the cold trout-streams, the boards giving back the clatter of our horses' feet:.... 
Meaning of the word marked with <WSD> tags:  (temperature) Having a slightly low temperature; mildly or pleasantly cold.