2014–16 El Nino event - this cycle was also observed between 1971–76, during post-El Nino intervals. Because of the high temperatures that persist in the months of April through October, most indoor workers in Houston spend the hottest part of the day in an air-conditioned environment. After World War II, air conditioning stimulated the growth of Houston, and was called the most air-conditioned city in the world in 1950. Autumn Autumn in Houston is warm, with temperatures averaging in the upper 60s to lower 80s °F (20-28 °C) during the day and in the 40s to lower 60s °F (10-17 °C) at night. Cool fronts that move through the region during the fall can bring rain. Hurricanes can move into the area from the Gulf of Mexico, bringing heavy rains and high winds. However, most years see little or no significant hurricane activity. Flooding most frequently occurs in October and November, which is the end of the Southeast Texas wet season. Most of these flood events result from remnants of Eastern Pacific cyclones interacting with upper-level boundaries; October 2015 was the latest example of such an occurrence, wherein the remnants of Hurricane Patricia brought over 9 inches of rain to the city. The latest hurricane to reach Texas was Hurricane Harvey in August 2017. Winter Winters in Houston are relatively mild, dry, and temperate compared to most areas of the United States. Houston winters are, on average, colder than South Florida and Southern California, on par with southern Louisiana and Central Florida, but slightly warmer than Dallas, Atlanta, San Antonio, Austin, and other inland southern cities. The average high in January, the coldest month, is and the low . George Bush Intercontinental Airport sees an average of 9.6 days per year of freezing temperatures. Cold fronts during the winter can bring nighttime lows that drop into the 30s but usually remain above freezing. The coldest weather of the season often includes temperatures in the low 30s to mid-40s at night. Hard freezes are not uncommon in North Houston; George Bush Intercontinental Airport has recorded at least one freeze every winter since it opened in 1969. However, areas in the central or southern parts of the Houston metro area are consistently several degrees warmer on the coldest winter nights. Areas south of Interstate 10 can have entire winters without a freeze. The coldest temperature ever recorded at George Bush Intercontinental Airport