What seasonal factor influences mosquito breeding in Illinois?

The correct answer highlights the significance of rainfall patterns during the spring and summer as a crucial factor influencing mosquito breeding in Illinois. Mosquitoes require standing water to lay their eggs, and periods of rainfall create numerous breeding sites in various containers, puddles, and low-lying areas. Spring and summer are typically when rainfall increases, providing the ideal conditions for mosquito reproduction.

The other factors mentioned, while relevant to the overall mosquito lifecycle and activity, do not play as direct a role in breeding. Temperature fluctuations can affect mosquito metabolism and survival but are not as decisive in creating breeding habitats. Wind speed might influence mosquito dispersal but does not facilitate breeding directly, and humidity levels in the fall and winter typically do not contribute to breeding since mosquitoes are less active in cooler months and may enter a dormant state. Therefore, it's the rainfall patterns during the warmer months that most significantly impact mosquito populations in Illinois.