Ocean Watch
By Susan Scott
The first year I lived in Hawaii, several friends and I made plans to spend a day at the beach. We donned our swimming suits, packed a picnic lunch and loaded the cars with windsurfers. Isle seasonal differences
are subtle yet noticeable"Where are you going?" a neighbor asked.
"Kailua Beach," I said. "Want to come?"
"What, are you crazy?" she said. "It's winter."
We newcomers to the islands thought this was a great joke because by mainland standards, every day in Hawaii was a sweet summer day.
But that was 20 years ago. Now, like almost everyone else who has lived here awhile, I, too, see differences between Hawaii's two seasons, winter (November to April) and summer (May to October).
On this Memorial Day weekend, the traditional launch of summer, here are a few features of Hawaii's summers I now notice:
>> The water is warmer. The average water temperature in Honolulu from January through April is 76 degrees, which is chilly by island standards. But in May the water begins to warm up. May, June and July have average temperatures of 78, 79 and 80 degrees respectively.
For the chicken-skin types, however, the months to go swimming are September and October when the water temperature reaches a high of 81 degrees. November's water is still nice and warm at 79 degrees, but in December it drops to a cool 77 degrees.
>> The air is markedly warmer. Hawaii's average daytime temperature at sea level during the summer is 85 degrees. In winter the average daytime temperature at sea level is a bone-chilling 78 degrees. (That's when we wear socks with our slippers.)
>> The days are longer. Hawaii's longest summer days are about 13 1/2 hours. Our shortest winter days are about 11 hours. This 2 1/2-hour difference seems like a lot of extra daylight to us Hawaii residents, but it's piddling to Northerners. In Maine the longest summer day is 15 1/2 hours, and its shortest winter day is 8 1/2 hours, giving them six more hours of summer daylight.
>> Summertime surf is small on the North Shore. This is because summer has settled in also over the North Pacific, meaning it's relatively calm up there. Our big North Shore surf comes from winter storms generated in the northern Pacific Ocean.
>> The surf is big on the South Shore. Hawaii's summertime is the Southern Hemisphere's wintertime. Winter storms in the South create waves that travel thousands of miles to Hawaii, giving us our summer south swells.
>> The humpback whales are missing. These migratory animals leave the islands around the end of April to spend the summer in their rich feeding grounds in Alaska. In November the whales begin returning to give birth and mate in Hawaii's warm waters.
>> Our migratory shorebirds are also gone. Four kinds commonly winter in Hawaii: Pacific golden plovers, ruddy turnstones, wandering tattlers and sanderlings. These birds head north for the summer to feed and breed. Summer is a lonely time for bird-watchers here, especially for those of us who host plovers in our yards. The shorebirds begin returning in August.
>> In general, Hawaii's summer weather is glorious. We have little rain, consistent tradewinds, low humidity and flowers popping out everywhere.
So now that summer is officially here, I'm going to get out the ocean toys, lather on the sunscreen and head for the beach.
And I will not put if off. I only have until October, after all.
Marine science writer Susan Scott's Ocean Watch column
appears weekly in the Star-Bulletin. Contact her at http://www.susanscott.net.
