We visited Nainital a few months back.
We reached at night in the month of May and it was a very chill night.
We had to walk to our hotel as there were some police restrictions for bus to go till the hotel. The Naini lake was in front of our hotel only.
The next morning, we went to Naini Lake. It was such a nice morning and a group of swans were swimming through the lake.
We took a boat to reach to the temple of Naini Devi.The boatman told us that this lake is in shape of an eye so it is called "naini lake".The water was very pure and very cold. Naini lake must be visited once in a life.