If you hate cold weather, then you are in luck! New Orleans is not a city known for being cold. In fact, the warm climate makes for a very mild winter and an early spring. The downside, of course, is that the end of summer is hot and muggy. You'll have a new appreciation for air conditioning.
Most of the year, the temperature is quite cooperative - if not during the day, then certainly during the evening. A nice warm stroll through the French Quarter on a summer evening is a great way to spend a vacation.
Besides the heat, there are two main weather conditions that you'll need to keep a watch for: rain and hurricanes. Rain can be quite intense and can cause flooding in the streets. Automatic pumps help the roadways clear quickly, but rain is not a weather condition to simply ignore.
And the other condition, of course, is a hurricane. The good thing about hurricanes is that there is plenty of warning before the storms make landfall. The best course of action when major hurricanes come is to evacuate the city (see our tips for building a hurricane evacuation kit for residents). If you decide to stay in the city, you need to make sure that you are prepared for the hurricane and its aftermath.