Choose the right style: During monsoon, prefer sunglasses with a fixed or pre-formed bridge (plastic or acetate) over those with nose pads, as the rain water will not enter your eyes. Also, there is no issue about the silicone nose pads getting dirty and falling off eventually.
For easy maintenance: Lenses with hydrophobic and super-hydrophobic coatings roll the droplets off the lenses, making it a hassle free, low-maintenance option.
Style wise: Sunglass styles like wayfarer, with lighter or gradient tints
and less curvature, are a better option than their darker counterparts, which may give relatively poor visibility in cloudy weather.
For UV protection: Photochromic lenses are a good option when choosing prescription spectacles as it protects eyes from harmful UV rays and pollution.
Avoid: Sunglasses with metal frames should be avoided. Instead, opt for plastic or acetate or shell frames to avoid skin infection due to rusting of the metal and conduction of heat.