Changes

* '''Wet''' As the water evaporates, it cools your body making the effective temperature much colder. Wet clothes also have far less insulation value , though wool and good synthetic fabrics are better than cotton. When running in cool conditions, it is important not to overdress and sweat through your clothing. Instead, try to carry excess clothing, or wear clothing that can be adjusted by opening zippers. * '''Wind''' The movement of air will suck the heat from your body, and if you are wet, it will increase the evaporative cooling. Remember that running in still conditions will create air movement over your body. * '''Rain''' Rain will obviously make you wet, but heavy rain will directly chill you. Torrential and torrential rain can rapidly trigger hypothermia .I've had mild moderate hypothermia when hiking on a 95f day when a summer storm occurred, soaking me cold rain.

* '''Slowing up''' Running generates a lot of heat, and generally makes the perceived temperature 20f warmer than the actual temperature. This means that slowing up or stopping can cause you to become chilled, especially if you've been running at a fasterpace. I have felt been comfortable while running in cool rain, and become mildly hypothermic within a couple of minutes of stopping, then moderately hypothermic within 10 minutes. * '''Sun down''' The risk of hypothermia increases when the sun goes down, partly because the heat from the sun is lost, but also this is the time that the temperature drops the fastest. In a long race, this is often a psychological and physiological low point, creating a perfect storm.