I love Jimmy Buffett.  He seems to have a song for every occasion.  Having played in a variety of cover bands over the years, I’ve covered Buffett tunes too many times to recall. And although I am pretty sure that I can cover it in my sleep,  “Margaritaville” is still great fun after all this time.  Even though my personal favorite is “Cheeseburger in Paradise”, I’d like to give a nod to “Changes in Latitude, Changes in Attitude”, both the 1977 album and title track.  Jimmy is on to something here, something I think all of us sense – that life is a little different where the north end of your range stops at the Florida Keys.

When Jimmy is off flying or sailing to “the islands” he could be almost anywhere in the Caribbean.  When my friends from Alaska head to “the islands”, it typically means that they are heading to 21°18’ 56” N Latitude, 157° 51’ 29” W Longitude:  Hawaii (the exact coordinates are for Honolulu).  Anytime between October and March (often October to March if they can).  The latitude here is important, because at 21° and change, the islands are tucked safely into the tropics, which extend from 23.5° south of the Equator to 23.5° north of it.

Let us ponder for a moment the thought of time in a tropical island setting for someone from Fairbanks, given the following:

Fairbanks in January:

Average high temperature:  1° F

Average low temperature: -17°F

Total hours of sunshine:  54

Honolulu in January:

Average high temperature: 80°F

Average low temperature: 66°F

Total hours of sunshine:  227

Change your latitude.  Change the duration and intensity of the Sun’s energy; change the nature and length of the seasons, dramatically change the length of days.  Now, latitude is not the only consideration, to be sure.  There is the small issue of the Hawaiian Islands being smack in the middle of the world’s largest body of water, with great temperature moderating capability.  Fairbanks, by comparison, is buried deep in central Alaska a good many miles from the moderating effects of any body of water (including the Arctic Ocean).  So for an Alaskan (or almost anyone else living in the northern hemisphere) a more moderate year-round climate and lots of year-round sunshine await just on the other side of the Tropic of Cancer (Cancer marks the north side of the tropics, Capricorn the south).

How about longitude?  Can your longitudinal position matter like your latitudinal position?  Let’s ponder the comparison of San Francisco, California, and Norfolk, Virginia:

San Francisco:  37° 46’ 26” N Latitude; 122° 25’ 53” W Longitude

Norfolk: 36° 51’ 02” N Latitude; 76° 17’ 09” W Longitude

There is certainly not a great difference in latitude between the two, although they are a continent apart with respect to longitude. Some climate data to consider:

Average daily temperature warmest month:  (SF) 63° F; (N) 80° F

Average daily temperature coldest month:  (SF) 49° F; (N) 44° F

Annual temperature range based on average daily data above: (SF) 14°; (N) 36° F

Ok.

Using the Weatherspark.com metrics for humidity:  if you are going to notice the feeling of humidity in the air in San Francisco, it is only likely in August, and does not always happen even then. In other words, you can live all year round in San Francisco without noticing a humid, muggy feeling in the air.  By comparison, you will notice the humidity from April to October, with “oppressive” humidity the norm from late May to mid October living in Norfolk.

So what’s going on?

Well, there is nothing particularly significant about the longitudinal settings of San Francisco and Norfolk.  It is significant that San Francisco is on the west side of the continent and Norfolk on the east.  Here is where global ocean circulation patterns come into play.  At a global scale the combination of heat transfer from the equator to the poles and the daily rotation of the earth’s axis creates circular patterns in fluid media (this would include both the atmosphere and the world’s oceans). In the Northern Hemisphere a clockwise rotation is established where warm water from the Atlantic equatorial area moves up the east coast of the United States, across the North Atlantic (where it starts to lose heat energy), and then down the western coast of Europe and North Africa before turning westward across the mid Atlantic to start the process all over again.  You know the warm water moving up the eastern US seaboard as the Gulf Stream; the colder water on the European side is known as the Canary Current (named for the Canary Islands).

The same thing happens in the Northern Pacific with the warm water Japan Current moving north in the far west Pacific, losing heat energy as it moves eastward across the Gulf of Alaska, and then returning south along the west coast of the US as the California Current.  In case you are wondering, the same phenomenon exists in the Southern Hemisphere, but with counterclockwise rotation.

There are other factors in play, including the prevailing westerly winds coming across the North Pacific before reaching San Francisco, whereas those same prevailing westerly winds reach Norfolk (during the summer especially) after a 3000 mile trip across a very warm North America.  However, the contrasting ocean currents play large in the differing temperature and weather patterns.  In short, warmer ocean waters translate to warmer temperatures and more humidity in the air.  If you like cooler temperatures, fog for precipitation, and a year-round lack of humidity, San Francisco is your place.  On the other hand, if you like swimming and playing in the water all day while at the beach, go to Norfolk.  Try that in Frisco’s Half-Moon Bay.  Don’t forget your wetsuit.

Adapted from lecture notes (2014), Changes in Latitude, what do they mean?