Final answer:
The lunch improves for August because the grain ripens properly due to less heavy summer rains, resulting in bread with its usual nourishing power and strength.
Step-by-step explanation:
In the given information, it is mentioned that the lack of ripened grain resulted in bread not being nourishing enough. This could have led to malnourishment and hunger among the people, especially the poor. However, as the season progresses and reaches August, the summer rains become less heavy, allowing the grain to ripen properly. Consequently, the bread made from this ripened grain will have its usual nourishing power and strength, improving the quality of lunch in August.
To summarize, lunch improves for August because the grain ripens properly due to less heavy summer rains, resulting in bread with its usual nourishing power and strength.