The route from Delhi to Naintal is very straightforward. One can take the NH9 to reach SH41 and then take NH109 to reach Nainital. The distance is 303 KM and takes about 7 hours to reach Nainital.
October to February: The winters see the temperature drop to as low as 0 degree Celsius and with snowfall, the hill station gets covered in Snow at the various peaks around Nainital. March to June: The summers are the best time to visit Nainital as the weather remains very moderate and is ideal for visiting the attraction around the town and exploring the region. July-September: Nainital doesn’t receive much rainfall even in monsoon but the rains can affect the roads and other means of transport to reach the town. All in all, the slight rains further beautify the city and make it lush green which is a sight to behold.
There are other routes that can be taken in case NH9 is closed. One can maneuver around NH9 by taking the NH9 via Meerut. This adds a further 50 km and 1 hr. to the journey time.
The road connection between Delhi and Nainital is through national and state highways and are thus very well maintained. Once you enter the Kumaon hills, roads get steep and narrow with very sharp turns but any experienced cab driver can easily drive around and take you to your destination.