The Sun's weather page erroneously shows Chesapeake Bay water temperatures nearly 20 degrees colder than the ocean.

The Sun's weather page erroneously shows Chesapeake Bay water temperatures nearly 20 degrees colder than the ocean. (Scott Dance, The Baltimore Sun)

We have a mystery on our hands — and an error to report — here on the Maryland Weather blog. I’ve received questions from astute reader Bob West in Ellicott City about dramatic fluctuation in Chesapeake Bay water temperatures, at least according to the Sun's daily weather page, found on the back of the sports section.

Until now, I didn't have an answer, other than to guess that the page must be wrong.

While Wednesday’s page read 36 degrees, as measured in the Inner Harbor, the true reading was more like 57, I'm told by the National Weather Service and AccuWeather, which provides the data used on the weather page. Ocean temperatures are in the mid-50s, and down the bay, reports are the same, with nary a cold spell this winter to bring coves and creeks anywhere close to freezing temperatures.

AccuWeather pulls its data for Chesapeake Bay water temperature from a National Oceanic and Atmospheric Administration sensor in the Inner Harbor, but Paul Walker, a senior meteorologist for the weather company, was unsure Wednesday why the wrong data was being reported on our weather page.

So it turns out my hunch was right. Marine weather experts like Bruce Michael of the Maryland Department of Natural Resources and Wendy McPherson of the U.S. Geological Survey's Baltimore office explained that air temperatures and winds can make surface temperatures abnormally warm or cold, potentially skewing temperature readings. But in general, water holds its temperature much more consistently than does the air, so a 20-degree difference between Inner Harbor water temperatures and temperatures in the ocean or further south in the bay doesn't quite add up.

Walker assured me AccuWeather is working on determining why the wrong numbers have been showing up periodically on the Sun's weather page. So until you see the water temperature reports for the bay a little closer to the mid-50s, assume they're still working on it. I'll keep you posted.