NOAA Web Site Link Tides and Currents Home Page Transparent placeholder image

Notice: We are experiencing a wide spread communication outage affecting the availability of water level and meteorological data for some of our stations, as well as several critical bridge clearance measurements. We are diligently working to resolve this data outage. Please direct all questions to or call (301) 713-2815.

Datums for 8459681, Block Island RI

NOTICE: All data values are relative to the MLLW.

Elevations on Mean Lower Low Water

Station: 8459681, Block Island, RI
Status: Accepted (May 1 2003)
Units: Feet
Control Station: 8452660 Newport, RI
T.M.: 75
Epoch: 1983-2001
Datum: MLLW
MHHW2.95Mean Higher-High Water
MHW2.71Mean High Water
MTL1.41Mean Tide Level
MSL1.37Mean Sea Level
DTL1.47Mean Diurnal Tide Level
MLW0.11Mean Low Water
MLLW0.00Mean Lower-Low Water
STND-8.20Station Datum
GT2.95Great Diurnal Range
MN2.60Mean Range of Tide
DHQ0.24Mean Diurnal High Water Inequality
DLQ0.11Mean Diurnal Low Water Inequality
HWI0.35Greenwich High Water Interval (in hours)
LWI6.61Greenwich Low Water Interval (in hours)
Max TideHighest Observed Tide
Max Tide Date & Time Highest Observed Tide Date & Time
Min TideLowest Observed Tide
Min Tide Date & Time Lowest Observed Tide Date & Time
HAT3.97Highest Astronomical Tide
HAT Date & Time10/16/1993 12:48HAT Date and Time
LAT-0.84Lowest Astronomical Tide
LAT Date & Time03/09/1993 07:06LAT Date and Time
Tidal Datum Analysis Periods
05/01/1998 - 10/31/1998

Products available at 8459681 Block Island, RI

Revised: 08/08/2018
NOAA / National Ocean Service
Web site owner: Center for Operational Oceanographic Products and Services