Step 1: Identify the rainy season.
The rainy season in India generally occurs from June to September. Therefore, we consider the rainfall data from June to September for calculating the total rainfall.
Step 2: Total rainfall calculation.
Rainfall during the rainy season is the sum of rainfall from June to September:
\[
\text{Total Rainfall} = 43.9 + 51.4 + 39.8 + 20.9 = 155.9 \, \text{cm}.
\]
Thus, the total rainfall during the rainy season is 155.9 cm.