2003 Boston Light Swim
Race Day Conditions
August 16, 2003
NOAA Boston Buoy #44013

Time (EDT) Water Temp Air Temp Dew Point Wave Height Wind Spd Wind Dir Pressure
8:00am 66.4°F 69.3°F 65.7°F 0.5 - 1.0 feet 11 mph 210° (SSW) 29.82
9:00am 66.4°F 70.9°F 66.0°F 0.5 - 1.0 feet 11 mph 240° (WSW) 29.82
10:00am 66.4°F 71.4°F 66.7°F 0.5 - 1.0 feet 9 mph 220° (SW) 29.80
11:00am 67.1°F 72.1°F 65.8°F 0.5 - 1.0 feet 9 mph 270° (W) 29.80
12:00pm 67.1°F 73.0°F 66.7°F 0.5 - 1.0 feet 11 mph 240° (WSW) 29.79
1:00pm 67.3°F 74.1°F 67.6°F 0.5 - 1.0 feet 9 mph 250° (WSW) 29.77
2:00pm 67.8°F 75.2°F 67.8°F 0.5 - 1.0 feet 7 mph 230° (SW) 29.75
3:00pm 68.5°F 75.6°F 67.8°F 0.5 - 1.0 feet 7 mph 230° (SW) 29.72

The above table lists weather observations at the NOAA Boston Buoy #44013, located 16nm east of Boston. Observations are made in degrees C for temperature, meters for wave height, meters per second for wind speed, and hectopascals for atmospheric pressure. The above data represents conversions from those units.

At the start, our boat recorded a water temperature of 60.4 degrees (using a Radio Shack digital thermometer). Another boat recorded approximately 64 degrees using a 'real' thermometer. Our Radio Shack thermometer was lost just before the start when it tangled with a lobster trap, so we were not able to get temperature observations for the rest of the race. Most swimmers commented that during the swim this year, the water temperature was warmer than expected, and was not as much of a factor as many had feared.

Sea conditions were relatively calm at the start. Though the tide was going in, the wind was blowing against the course, so swimmers faced wind chop coming at them. After rounding George's Island, this wind chop became stronger, and boat traffic started to increase (since it was past 10:00am). As a result, waves from boats also played a significant factor. In the crossing between the start and George's Island, all but the lead two or three swimmers had to deal with the Provincetown II boat crossing in front of them at high speed.

Along the back side of Rainford Island, boat traffic abated somewhat. Once swimmers turned under the Long Island bridge, boat traffic increased significantly, and there was significant boat wake from the Long Island bridge all the way to the finish. In this stretch, it was also very important for escort boats to remain close, as most pleasure boats out on the water clearly did not expect to see a swimmer in the water, and were passing very closely.

At the start, sky conditions were mostly sunny. As the race continued, the sky turned hazy and progressed to partly cloudy and very very hazy by the finish.