Kylie spends a winter day recording the temperature once every three hours for science class. At 9 am, the temperature was -5.9°F. Between 9am and noon, the temperature increased by 14.3°F. Between noon and 3pm, the temperature went down 10.8°F. Between 3pm and 6pm, the temperature decreased by 8.4°F. What was the temperature at 6pm?