Final answer:
The plague reached its climax during the summer months, as supported by historical and scientific evidence indicating heightened infection rates and immune system activity during this season.
Step-by-step explanation:
The plague, particularly during the Second Pandemic, including events known as the Black Death, demonstrated a clear seasonal pattern in its spread and intensity. Scholarly research, including the studies of medieval testaments by Cohn, indicates that the plague in Mediterranean Europe reached its climax in summer, peaking around June or July. However, in northern regions, like London, data suggests a differing seasonal pattern, aligning still with warmer seasons. Evidence from scientific studies supports the notion that the immune system's variability, particularly in phagocytes which are crucial in fighting the plague, follows seasonal patterns, with higher bactericidal activity in summer.
Seasonal variation in both hosts and pathogens played a significant role in the prevalence of plague outbreaks throughout history. It's important to note that Europe's epidemiological experience with the plague stretched way beyond the initial pandemic in the 14th century, with recurrent waves lasting into the early modern period, and even into the 19th century in some regions.