What is the difference between Sawan Shivratri and Mahashivratri? Why Mahashivratri is celebrated in Sawan

Sawan Shivratri and Mahashivratri: Both Sawan Shivratri and Mahashivratri festivals are dedicated to Lord Shiva, both involve fasting and Jalabhishek. However, Sawan Shivaratri and Mahashivaratri are not the same.