We would advice you to NOT buy your winter jackets in India. The temperature here varies from as high as 35°C in summer to -10°C in winter. The jackets that most people brought from India did not get do them any good once the temperature went close to even -3°C. They also end up taking a lot of luggage space in your bags. Here, a good durable good winter jacket would cost you $40-60, so bring some extra cash. You have lot of time to buy it once you get here. The temperature doesn’t start dropping till about the first week of October.
Other winter wear like sweaters, sweatshirts, woollen socks, gloves, ear muffs (if you think you need them), thermal underwear can be brought from India. If you like wearing leather jackets (not essential) you may want to get it from India as there are really expensive here, but the winter jackets that you get here are quite good and CHEAP.
It would be a good idea to get an umbrella and/or a raincoat. Whether winter or summer you’ll mostly be roaming around in Sneakers. So get a good pair from India. We suggest that you get comfortable footwear like Slippers: Hawais and Leather/Sports Sandals from India itself as they are expensive in the U.S. unless there is a sale. Again emphasizing get enough and comfortable pairs as you have to walk long distances. There is no need to buy a new pair of sport shoes from India as you get them dirt cheap out her, atleast the unbranded ones which last real good. Also the branded ones like Nike, Adidas, Reebok can range anywhere from $25 to $75 and you get regular sales here on them.
Summers are warm with temperature at times going upto 35°C. So you need to bring shorts and cotton T shirts. Get atleast 3 to 4 pairs of jeans. Account for the fact that your waist size may not remain the same (for the better or for the worse !). You will need to bring about half a dozen good shirts. Do bring some traditional Indian garments like saris, salwar-kameezes, kurta-pyjamas, you do get to show them off at Indian festivals and international gatherings. Try and bring some formal attire too. A blazer or a suit, ties, a formal wear shirt, a skirt-suit etc (though you get better ones here but there are expensive). These are useful during professional meetings and interviews. Last but not the least, unless you are fond of doing your laundry often, get enough undergarments to last you for at least 2-3 weeks! The numbers here are all relative. Bring more or less accordingly.
Other useful items are a blanket(not essential as you end up buying a comforter here), bedsheets(double sized as single sized ones would be small for the beds here), pillow covers, towels, napkins. Also, make sure the bed sheets that you bring are the larger size ones, like the ones from Bombay dyeing or Fabindia and make sure the clothes that you bring do no bleed color as you will be putting then in the washer/dryer.