The best time to visit Mirjan Fort is from September to February. You may encounter unpredictable showers till mid-September, but after that, the surrounding area is blooming with flowers and a lush green atmosphere. Even within the fort, there are several open-spaced grasslands with new vegetation budding across.
You can also visit the fort in summers, but the heat of the sun may tear you down, so carry umbrellas, hats, sunglasses, and sunscreen for protection. Monsoon is usually accompanied by thunderous rainfall, which makes it difficult to sightsee the open spaces of the fort.