NOAA Tides and Currents

Get the moon phase for a date (or each day of a date range if end_date is given): phase name (New Moon, Waxing Crescent, ...), illuminated fraction, age in days within the 29.53-day cycle, distance (km), apparent diameter (degrees), and waxing/waning. Tide context: spring tides (largest range) occur just after new and full moons; neap tides after quarter moons. Computed locally — no NOAA data involved.

Find the date(s) of the next occurrence(s) of a principal moon phase (New Moon, First Quarter, Full Moon, Last Quarter) from a starting date. Use for: "when is the next full moon?", planning around spring tides (which follow new/full moons by 1–2 days).

Find the next occurrence(s) of a sun event (sunrise, sunset, dawn, dusk, solarNoon, night, nightEnd, goldenHourStart, goldenHourEnd, nauticalDawn, nauticalDusk, astronomicalDawn, astronomicalDusk) at a location from a starting date. Use for: "when is sunset today?", planning golden-hour photography or dawn fishing around tide windows.

Get the sun's position for a date, time, and location: azimuth (degrees clockwise from north as rendered here), altitude above the horizon (degrees), plus approximate declination and right ascension. Use for: shadow/lighting analysis, solar exposure. Computed locally with suncalc; declination/RA are approximate.

Get sunrise, sunset, solar noon, dawn/dusk (civil), nautical dawn/dusk, astronomical dawn/dusk, golden hour, and day length for a location and date (or each day of a range if end_date is given). Times are ISO UTC unless an IANA timezone is provided. At high latitudes some events may be null (e.g. no astronomical night in summer). Computed locally.

Find the NOAA stations closest to a latitude/longitude point, sorted by distance. Use this to answer "what's the tide station near <place>?" — geocode the place to coordinates first, then call this. Filter by type to match the data you need (e.g. type "tidepredictions" before calling noaa_get_tide_predictions, "currents" before noaa_get_currents — current stations have different IDs than water-level stations). Distance is computed great-circle (Haversine) and reported in both km and miles. (NOAA's API has no native coordinate search; this tool maintains a cached station directory.)

Get predicted tidal currents for a NOAA current prediction station. interval="max_slack" (recommended for navigation) returns the tidal-current events — maximum flood, maximum ebb, and slack water times — up to 1 year per request. Other intervals (h, 1, 6, 10, 30, 60 minutes) return a velocity time series — up to 31 days. UNITS WARNING: english = knots; metric = cm/s. vel_type="speed_dir" returns Speed/Direction pairs; "default" returns velocities projected on the flood/ebb axis (Velocity_Major: positive = flood direction, negative = ebb) with meanFloodDir/meanEbbDir. Subordinate (type "S") prediction stations derive from a reference station — see noaa_get_prediction_offsets.

Get observed current speed and direction from a NOAA current meter station. Current stations use alphanumeric IDs (e.g. "cb0102" Chesapeake, "bh0101" Boston Harbor) — NOT the 7-digit water-level station IDs. Find them with noaa_search_stations (type "currents") or noaa_find_nearest_stations. UNITS WARNING: english = knots, but metric = cm/s (centimeters/second, not m/s). Returns per record: t (time), s (speed), d (direction, degrees true), b (bin number). Max 7 days per request. Set expand_detailed=true to include per-beam echo intensity and correlation diagnostics.

Get NOAA's extreme water level exceedance statistics for a station: the annual exceedance probability levels (e.g. the 1%-annual-chance "100-year" level) and historical extreme events, computed from the station's verified record. Use for flood risk questions ("what water level has a 1% chance per year at X?"). Levels are relative to the station's datums for the 1983–2001 epoch. Only long-record stations have this product.

Get the harmonic constituents NOAA uses to compute tide or current predictions at a station — the amplitude, phase, and angular speed of each tidal constituent (M2, S2, N2, K1, O1, ...). For water-level stations: amplitude (feet/meters), phase_GMT and phase_local (degrees), speed (degrees/hour). For current stations (alphanumeric IDs) constituents are current ellipses (major/minor amplitudes and phases per depth bin — pass bin to filter). Use for: building custom tide computations, checking a station's dominant constituents (M2 amplitude indicates semidiurnal range), verifying whether a station is harmonically predicted at all. Only reference (R) stations have constituents — subordinate stations use offsets (noaa_get_prediction_offsets).

Get NOAA high tide flooding (HTF, "nuisance"/"sunny day" flooding) statistics for a station. Reports: - daily: flood occurrence per day (REQUIRES start_date and end_date, YYYYMMDD) - monthly / seasonal / annual: counts of minor/moderate/major flood days per period (filter with year/month/season_months, or range = last N periods) - met_year_annual: counts by meteorological year (May–April) - annual_outlook: NOAA's projected flood-day outlook for the coming met year - projections: decadal flood-day projections through 2100 (filter by decade, flood_threshold) - record_days: record flood-day counts - likely_scenarios: likely decadal flooding scenarios - daily_likelihoods: day-by-day flood likelihood forecasts Use for: "how often does X flood?", trends in nuisance flooding, future flooding projections. Not all stations have HTF products — check the HTFhistorical flag via noaa_get_station_info.

Get observed meteorological/oceanographic sensor data from a NOAA station. Products: air_temperature, water_temperature, wind (speed/gust/direction), air_pressure, air_gap (bridge clearance to water surface), conductivity, visibility, humidity, salinity. Units by system: temps °F/°C; wind knots (english) or m/s (metric); air_gap feet/meters; visibility nautical miles/kilometers; air_pressure always millibars; salinity always PSU. Max span ~31 days per request; interval "6" (6-minute, default) or "h" (hourly). Not every station has every sensor — check with noaa_get_station_info (expand ["sensors"]). Water-level data is served by noaa_get_water_levels, not this tool.

Get the offsets a subordinate (type "S") prediction station applies to its reference station's predictions. kind "tide": returns refStationId, time offsets for high/low tide (minutes), height offsets for high/low tide, and whether the height adjustment is a ratio (multiplied) or fixed value — this is how NOAA derives subordinate-station tide times from the reference harmonic station. kind "current": returns refStationId/bin, mean flood/ebb directions, and time adjustments (minutes) for max flood, slack-before-ebb, max ebb, slack-before-flood plus amplitude ratios. Note: current prediction offsets are indexed per bin — pass the station_bin_suffix ID form (e.g. "ACT0091_1") if the plain ID returns nothing. Reference (R) stations return empty/null offsets — they don't need any.

Get curated reference documentation for NOAA CO-OPS concepts and parameters. Topics: - products: Every NOAA CO-OPS data product and which tool serves it - datums: Vertical datums (MLLW, MSL, IGLD...) and station applicability - units: What english vs metric means per measurement (incl. cm/s currents) - time_zones: gmt / lst / lst_ldt semantics and restrictions - intervals: Valid interval values per product family - station_types: Station type filters and station ID formats - data_limits: Maximum date-range span per product - quality_flags: Data quality fields (v/s/f/q), flag letters, HH/H/L/LL - date_formats: Accepted date formats and parameter combinations Consult this before constructing unusual requests — especially "datums" (which vertical reference to use and station applicability), "units" (english/metric asymmetries like cm/s current speeds), and "data_limits" (maximum date spans per product).

Get NOAA's Interagency Sea Level Rise Scenario projections for a station (from the 2022 technical report): projected relative sea level (meters or feet, see units field) per decade through 2150 under the chosen scenario. Scenarios: low, intermediate-low, intermediate, intermediate-high, high, extreme, or all. Use for coastal planning questions ("how much sea level rise is projected at X by 2050?"). Pair with noaa_get_sea_level_trends (observed) and noaa_get_high_tide_flooding (flooding impact).

Get the long-term relative sea level trend at a NOAA station: trend and error (reported by NOAA in mm/yr or inches/decade — the payload's trendUnits field says which), the observation period (startDate/endDate), and seasonal amplitude. Relative sea level combines ocean rise AND local land movement (subsidence/uplift), so trends vary widely by station (e.g. strongly positive on the Gulf Coast, negative in Alaska). Requires a station with a long water-level record; omit station to list all (affil "US" or "Global" filters the network).

Get the accepted tidal datum values for a station: the elevations of MHHW, MHW, MTL, MSL, DTL, MLW, MLLW, STND, NAVD88 (where computed), plus GT (great diurnal range), MN (mean range), LAT/HAT (lowest/highest astronomical tide), and the station's historical extreme min/max water levels with dates. epoch "current" returns the present National Tidal Datum Epoch (1983–2001) values; "superseded" returns the prior epoch's values (useful for historical comparisons — not all stations have one). All values share one reference zero (the station datum), so datum-to-datum conversion is subtraction: height_above_MLLW = height_above_MSL + (MSL − MLLW). Use this tool to (1) check which datums a station supports before requesting data, and (2) convert heights between datums.

Get a NOAA station's full metadata record: location, state, time zone, tide type, Great Lakes flag, capability flags, and links to available sub-resources. Optionally expand sub-resources inline via the "expand" list: - details (established/removed dates), sensors (installed instruments + elevations), floodlevels (NOS/NWS minor/moderate/major flood thresholds), benchmarks, products (available data page links), notices, disclaimers — for water-level stations - bins (ADCP depth bins), deployments — for current stations (alphanumeric IDs) Use this before requesting data to confirm what the station actually collects. For datum values use noaa_get_station_datums; for harmonic constituents use noaa_get_harmonic_constituents.

Get NOAA harmonic tide predictions (future or past) for a station. interval="hilo" (recommended for "when is high/low tide") returns the daily tide events with type H/L — up to 10 years per request. Other intervals (h, 1, 5, 6, 10, 15, 30, 60 minutes) return a height time series — up to 1 year per request. Heights are relative to the requested datum (MLLW default). Notes: - Great Lakes stations have NO tide predictions (lake levels are not tidal). - Subordinate stations (type "S") only support interval=hilo; use the station's reference (R) station for interval series. - Predictions are astronomical only — they exclude weather effects (storm surge, wind setup). Compare with noaa_get_water_levels for actual conditions.

Get a station's highest recorded water levels: analysis "toptenwaterlevels" returns the ten highest events on record (with date, height, causal event name like "Great New England Hurricane", and category); "peakwaterlevels" returns peak event records (optionally filtered by year). Heights are relative to the requested datum (MHHW is typical for flood comparisons). Use for "what's the worst flooding ever recorded at X?".

Get verified summary water-level products from a NOAA station: - high_low: each day's observed highs/lows with ty = HH (higher high), H, L, LL (lower low). Max 1 year per request. - daily_mean: daily mean levels — GREAT LAKES STATIONS ONLY; NOAA requires local standard time, which this tool applies automatically. Max 10 years. - daily_max_min: daily maxima/minima from hourly and 6-minute data with completeness percentages. Max 10 years. - monthly_mean: monthly tidal datum means (columns MHHW, MHW, MSL, MTL, MLW, MLLW, DTL, GT, MN, DHQ, DLQ, HWI, LWI, highest, lowest). Max 200 years — ideal for long-term climatology. Use for: historical extremes, mixed-tide analysis (HH vs H), long-term averages. For raw time series use noaa_get_water_levels; for future tides use noaa_get_tide_predictions.

Get observed water levels from a NOAA tide station as a time series. Choose the interval: "6" = standard 6-minute observations (preliminary or verified, max 31 days per request), "1" = 1-minute preliminary data (max 4 days), "hourly" = verified hourly heights (max 1 year). Heights are relative to the requested datum (MLLW by default — the US nautical chart zero). Returns per record: t (timestamp in requested time zone), v (height), s (sigma), f (quality flags, decoded in output), q (p=preliminary, v=verified). Recent data is preliminary; verification takes days to weeks. Use for: "what is the water level right now" (date=latest), storm surge analysis, comparing observed vs predicted tide. Do NOT use for future tides — use noaa_get_tide_predictions.

Search the NOAA CO-OPS station directory by capability type, name, and/or state. Filter with: - type: what the station does (waterlevels, tidepredictions, currents, currentpredictions, met, ...) — pick the type matching the data you plan to request. - name: case-insensitive substring ("San Francisco", "Boston"). - state: two-letter code ("CA", "MA"). Returns id, name, location, tide type, Great Lakes flag, and for prediction stations whether they are reference (R, harmonic) or subordinate (S, offset-based — hilo predictions only). Results are paginated (limit/offset). For proximity search by coordinates use noaa_find_nearest_stations instead.