Temperatures in the hills of the Western Ghats remain below 25°C due to altitude.
This statement appears to be correct. The Western Ghats, which run parallel to India's western coast, experience lower temperatures due to their elevation (altitude). Higher altitudes typically have cooler temperatures, and this mountain range can maintain temperatures below 25°C even during the hot season when surrounding lowland areas experience much higher temperatures.
The mean daily minimum temperature in the coastal regions rarely goes below 26°C.
This statement is also likely correct. Coastal regions in India benefit from the moderating effect of the sea, which helps maintain relatively stable temperatures. During the hot weather season, the proximity to large water bodies prevents coastal areas from experiencing the extreme temperature drops that inland areas might face at night.
North India experiences a milder hot weather season compared to South India.
This statement appears to be incorrect. North India, particularly the Indo-Gangetic plains, typically experiences more extreme hot weather compared to South India. During summer months (April-June), cities like Delhi, Lucknow, and other northern plains can record temperatures exceeding 45°C. South India generally has a more moderate climate due to its proximity to the sea on three sides.