Water Temperature Live

THE TIME AND PLACE BEHIND THE NUMBER

Clear sources.
Useful context.

Water Temperature Live brings official station observations and tide predictions into a simple planning view. Each reading keeps its identity, source and observation time.

Water temperatures are station observations

The initial catalogue uses reviewed NOAA CO-OPS monitoring locations. The reading applies to the named sensor at its coordinates. A harbor, pier, shallow beach and offshore buoy can have different temperatures. We do not imply that one station measures an entire city or coastline.

We retain source quality flags, reject missing or non-finite values, and withhold failed quality checks from the primary reading. An observation older than three hours is labeled old. Download time does not change observation time. The local worker checks selected temperature feeds about every ten minutes.

Tides are astronomical predictions

NOAA CO-OPS supplies high/low events and supported detailed prediction curves. Heights are shown above Mean Lower Low Water (MLLW). Times use the destination's IANA timezone and daylight-saving rules. Subordinate stations that support only high/low events do not receive a fabricated continuous curve.

A tide table does not include storm surge or predict tidal currents. Great Lakes pages show local water-level context instead of ordinary ocean tide predictions. Tide events are cached in advance and checked daily.

Daylight planning

Sunrise and sunset are calculated using Astral at the station coordinates. The planner filters official low-tide events against that day's daylight and your chosen local hours. Its “lowest” result is the lowest matching prediction in the selected date range. Access conditions and exposed terrain depend on the particular shoreline.

History and seasonal averages

The target baseline uses the five most recent complete calendar years (currently 2021–2025) of hourly observations from the same NOAA station. A calendar month needs at least three qualifying years. Each station-month-year needs at least 70% of its expected hourly values. The displayed percentile range uses the qualifying hourly readings, with the years and calculation method shown. Collection happens gradually in the background; incomplete months remain unpublished.

Weather alerts and local beach advisories

Weather forecasts and alerts come from the National Weather Service. Alert queries use the station point. A failed feed keeps the last received warning and its original expiry; an expired warning is not relabeled active. “No active alert reported” describes this feed's coverage.

Current local water-quality closures are not yet integrated. Check the responsible authority before a visit:

Buoy and lake context

Where provided, NDBC buoy temperature and wave measurements identify a separate instrument and observation time. Significant wave height is distinct from breaking surf height. Great Lakes station temperatures are local observations, rather than whole-lake averages. Lake level retains its IGLD reference and preliminary/quality labels.

Water temperature map

The colored water is NASA / JPL's daily MUR sea-surface temperature analysis, delivered by NASA GIBS. Its date appears beside the legend. The legend uses the exact published image palette; changing °F/°C converts its numeric labels. Land and water without analysis remain unshaded. Colors are an analysis of surface conditions, not a live thermometer at every beach.

Numbered white labels show the separate NOAA station measurements, with their own observation times. Gray dashed labels marked OLD retain historical readings. Select a station for its timestamp and tide information. No values are spread or interpolated from these stations to color surrounding water. The MUR product documentation describes the analysis and its limitations.

The maintenance service checks NASA availability and the corresponding palette every six hours and keeps the last successful result after a source failure. An analysis older than seven days is labeled as older data. The browser fetches only visible imagery tiles, and the layer turns off with an unavailable message if tiles fail. Turning water colors off leaves station measurements and the base map visible.

Clicking water for a temperature

Click or tap the water to read the native-resolution NASA MUR image pixel at that coordinate. Its exact color identifies an interval in the published temperature palette. The displayed approximate temperature is the interval midpoint; the interval and analysis date appear with it. Values beyond the color scale show a bound instead. These are daily surface-analysis estimates, separate from station measurements.

Transparent pixels on land or outside the analysis report no data. An unavailable image or an unrecognized color reports unavailable rather than guessing a value. The browser holds up to eight sampled tiles in memory and converts the same reading when you switch units. A click does not create a new server data record or log message.

Search accepts US ZIP codes, ZIP+4, city/state names and monitored station names. ZIP/city positions come from the locally cached GeoNames US postal catalogue, used under its CC BY 4.0 license. The US location directory combines postal city names with incorporated places and census-designated places from the 2025 US Census Gazetteer. Census places use their published reference position; postal-only city positions summarize that city’s postal locations. These are approximate navigation points, not street addresses or water instruments. Where shown, land/water area refers to the Census place or ZIP Code Tabulation Area (ZCTA), which can differ from a postal boundary. Mapped water area includes water of different kinds and does not establish shore access or sensor coverage. Overseas military postal routes are excluded.

Each city and ZIP has a permanent page, even without a local reading. A location search opens that page and centers a roughly 100-mile-wide map and lists monitored stations within 50 miles. Water shading remains available where the NASA analysis covers the view, even when there is no nearby pilot station. No station measurement is moved to a ZIP/city location. The maintenance service checks the catalogue monthly and keeps the last successful version after a download failure. Searches read the local cache, so they require no visitor request to an external geocoder.

Approximate location and nearby discovery

The map uses FreeIPAPI to estimate a city-level area from the visitor's public IP. The browser makes this request directly, so a visitor receives their own network's estimate. The initial map is about 100 miles across, and the nearby station list uses a 50-mile radius. That browsing radius is independent of the location estimate's accuracy, which varies with the network and VPN routing.

Only rounded coordinates and the area label are cached in your browser for 24 hours; the IP address and full provider response are not saved by this feature. No GPS permission is requested. Choose All places, search for a destination, or move the map and choose Use map center to override the estimate. A chosen region or destination search takes priority over automatic location.

Maps use the locally hosted Leaflet library and attributed OpenStreetMap tiles. The browser requests tiles for the visible map and honors their cache headers. The initial pilot has 20 stations, so some 50-mile areas have no covered station; the map keeps your chosen range and offers the full catalogue.

Sources and reuse

Water Temperature Live is an independent local website and is not endorsed by NOAA or NWS. Source credits identify where information originated. Every chart has a table equivalent. Unit changes convert the same underlying values.

Corrections and operation

When reporting a discrepancy to the site operator, include the station ID, time, page URL and official source. The local maintenance dashboard shows recent collection attempts and source errors. Routine collection runs without an active coding session.