The purpose of this website is simple: to provide AT and PCT hikers with a reliable and easy way to obtain weather for their location. Simply pick your trail, state and location from the lists below and the National Weather Service (NOAA) forecast for that location will appear.
One of the risks associated with hiking is exposing oneself to cold weather threats. Two of the major threats relate to hypothermia and frostbite.
Hypothermia is defined as a body core temperature of less than 95 degrees F (35 degrees C). Defined in this way, it does not necessarily take cold air temperature to result in hypothermia; cold weather is however the most common cause of hypothermia. The onset of hypothermia is indicated by shivering and mental confusion, with progressing mental confusion and an increased risk of the heart stopping as the condition progresses. Treating mild cases of hypothermia generally involve warm drinks to increase core body temperature, as well as warm (and preferably dry) clothing and, if possible, physical activity.
Frostbite occurs when skin damage results from freezing. It is most likely to occur in fingers and toes (body parts that are far from the heart) and any skin that is directly exposed to cold air. As frostbite progresses and deepens, a loss of feeling to the affected area is indicated. In the most extreme cases, gangrine may set in and result in surgery for the removal of dead tissue and extremeties.
One of the considerations to take into account in planning a cold weather hike is wind chill. This is the apparent temperature felt by the human body due to direct exposure to wind in cold temperatures. Generally speaking, moving air will feel colder than still air.
The impact goes beyond just feeling though. Frostbite and hypothermia become much greater risks in low wind chill conditions. One way to protect yourself is to know what the conditions are expected to be ahead of time. The forecasts shown on AT Weather will explicitly indicate a wind chill when conditions warrant it, but you can utilize this wind chill chart to calculate wind chill for any conditions up to 50 degrees Fahrenheit:
One of the best ways to prepare for cold weather hiking is to avoid cotton, which loses its insulating capability when wet (due to sweat, for instance), and to utilize a layering system for clothing:
Base Layer: this layer sits next to your skin, and wicks away sweat to prevent getting chilled. Clothes made from wool (light- to mid-weight) and various polyester-based synthetics make good base layers.
Insulating Layer: the insulating layer traps your body heat. It can also be wool (usually mid- to heavy-weight) but can also be fleece or down.
Shell: the shell has the dual purpose of wind protection and layering against precipitation. Shell materials vary in thickness and waterproof capability. In the summer, a thinner material is usually sufficient, but extreme weather conditions call for something thicker and waterproof, such as Gortex.
As you head outside in challenging weather conditions, nothing stands in the place of good judgement and common sense. The information presented here is for informational purposes only and is not intended as a complete guide to preparedness for inclement weather conditions.