Where do we get our temperature
information?
An unheated swimming pool’s water temperature will
usually match the average air temperature for the
preceding week. If the pool is warmer than the air after a
cold front passes through, the pool will give up heat
energy through evaporation until the air and water
temperatures are the same.
Think of it this way: You run your air conditioner during
the summer to cool your home. If you were to open all
the doors and windows on a hot summer day, the indoor
air temperature would rise to match the outdoor air
temperature within a fairly short time. At some point, the
indoor and outdoor air temperatures would be the same.
Your pool goes through the same balancing act, only in
reverse.
So the unheated pool temperatures you see on the this
page are the same as the 10-year average air
temperatures for each three-month season at the
latitude and longitude of the reference city.
Our data comes from 10 years of NASA weather data.
Unlike measurements taken at an airport, the NASA data
represent an average for an area measuring one
degree of latitude by one degree of longitude. Naturally,
actual temperatures within this area will vary: a bit
warmer in urban surroundings and a bit cooler in rural
surroundings