The author's central idea about the weather conditions in 1871 Chicago is that the city experienced extreme heat and drought, which contributed to the devastating Great Chicago Fire. This central idea is supported by three pieces of evidence:
1. The author describes the "scorching temperatures" and "unrelenting heat" during that time. This evidence indicates that Chicago was experiencing unusually high temperatures, suggesting a heatwave and drought.
2. The author mentions that the dry conditions caused by the lack of rainfall created a perfect environment for fires to spread rapidly. This evidence suggests that the drought made the city more susceptible to fires, making it easier for the fire to quickly grow out of control.
3. The author notes that the strong winds that accompanied the fire only worsened the situation. This evidence implies that the combination of the heat, drought, and wind created a perfect storm for the fire to spread quickly and destroy a significant portion of the city.
Each piece of evidence supports the analysis of the author's central idea by highlighting the extreme weather conditions in Chicago during 1871. The scorching temperatures, drought, and strong winds all contribute to the understanding that these weather conditions were significant factors in the severity of the Great Chicago Fire.