Barometric pressure is the weight of air in a particular area, which is measured in inches in mercury (inHg) or hectopascals (hPa). Though the degree of air pressure in any place continually fluctuates, some areas experience greater fluctuations than others. In the US, the places with the smallest range of barometric pressure changes are Honolulu, Hawaii and San Diego, California. Since large fluctuations in pressure, particularly decreases, are thought to cause or exacerbate a variety of health problems, many people prefer to live in areas with fewer changes.
Biggest and Smallest Ranges
Honolulu, Hawaii is the place in the US with the overall smallest range of changes in barometric pressure, ranging from 29.34 to 30.32 inHg (993.56 to 1026.75 hPa). San Diego is the city with the smallest range of changes in the continental US, with an average range of about 29.37 to 30.53 inHg (994.58 to 1033.86 hPa). Although places like Denver, Colorado may consistently have low pressure, they may also have a greater range of pressure changes. As for the places with the greatest range of pressure changes, St. Paul, Alaska ranges from 27.35 to 30.86 inHg (926.18 to 1045.04 hPa). In the contiguous US, Charleston, South Carolina has the largest range of changes, with a 27.64 to 30.85 inHg (936.00 to 1044.70 hPa) range.
Barometric Pressure Defined
Barometric pressure, also known as air pressure or atmospheric pressure, is the weight of the air, as measured by a barometer. Low pressure means that there is less weight pushing down. It also indicates that the air is rising and cooling, which helps to form clouds. High pressure means that there is more weight and indicates the presence of sinking air that is warming and less humid. Pressure at higher altitudes is adjusted to what it would be at sea level in order to provide a uniform reading.
Causes of Pressure Changes
The air pressure of an area is affected by several factors, including the gravity of the Earth in general, and the temperature and altitude of specific areas. Places at higher altitudes have less pressure than those at lower altitudes, and warmer places have less pressure than colder ones. Weather changes also affect barometric pressure, especially storms, which are preceded by decreases in pressure. Solar winds, which are powerful streams of charged particles with magnetic fields that affect the Earth's atmosphere, are also thought to raise atmospheric pressure incrementally.
Related Health Problems
Changes in barometric pressure are thought to be related to a wide range of health problems, though most of the evidence is anecdotal. Many people with arthritis experience increased joint pain when barometric pressure decreases, such as before a storm, and people also tend to be more prone to general aches and pains when barometric pressure decreases. Many people also experience congestion and sinus headaches, which may be because the changes in pressure can cause air to get trapped in the sinuses. Many people also find changes in pressure to be a trigger for migraines, but this varies from person to person.
Some people may experience inner ear problems, such as ear pain and dizziness. This is particularly common in people who have existing health problems related to the inner ear, like Meniere's disease. A 2001 study by Bianchi-Demicheli et al. also found that pressure changes were connected with pelvic pain, miscarriages, and vaginal bleeding, though the reason for the correlation is not clear.