Seasons in northern latitudes have a serious impact on religion, culture, society, and the way people interpret the world. When people traveled they would have notice the lack of seasons.
How did they explain this? What did they think was happening? Did this affect behavior (such as traders planning routes with seasonal goods)?
I'm region agnostic on this question.
Can you specify a time period you're interested in? The 15th-16th centuries with Europeans? The 9th-14th with Persian and Arab explorers?