What is most notable about Section 5's opening description and why?

It is most notable because of the fact that for the first time the description shows little change in time. By this point, the reader should expect that the natural description at the beginning of each section act as a metaphor for the upcoming monologues. The reader should surmise that the upcoming section will feature a similar situation to the previous section. At the same time, the reader should also suspect that there may be something shocking at this point in the novel. It is both the mid-point of the text, and Woolf has made a notable, significant change in this section's introduction. Additionally, the description features objects which are clearly outlined with the sun's full force now in effect.