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Usage Notes

General

All times are recorded in Coordinated Universal Time (UTC) and converted to your device’s local time for display.

All wind directions are relative to True North.

Charts for wind, temperature, pressure, and humidity are rendered using the Highcharts Library. Features include:

• Hover to inspect values at specific timestamps.
• Click legend entries to toggle chart lines.

Highcharts is a commercial library offered free to not-for-profit organizations such as NSC.

Wind Data Accuracy and Reliability

The weather station is installed on the lighthouse at the harbour entrance. Winds from northwest to northeast (a 90° sector) reach the station unobstructed, yielding reliable data. Winds from the northeast through west (a 270° clockwise sector) are partially blocked by land, trees, and buildings. This results in under-reporting and greater variability in both direction and strength compared to open-lake conditions.

Note: If the station is offline, the connection fails, or the WeatherLink Cloud is unavailable, the last received values are reused, leading to flat (unchanging) chart lines.

Weather Station Data for 6-Hour Charts

Every 5 minutes, the NSC weather station uploads its sensor data to Davis WeatherLink Cloud Storage (WLL) via a small device connected to the internet through the office router.

The NSC server fetches the latest 5-minute data set and appends wind, temperature, pressure, and humidity values to a continuously updated 6-hour data file. This cycle starts on the hour and updates every 5 minutes. It takes about 15 seconds for the latest data to be processed and reflected in the plots.

When this page is loaded or reloaded, your browser downloads the 6-hour file and renders the charts locally. To refresh the charts, reload the page.

WLL data is also available on external platforms including: Sailflow, WeatherLink, Weather Underground, and CWOP.

The NSC Weather WLL graphic displayed below comes directly from the Davis WLL site and auto-refreshes every minute. Note: seasonal rainfall totals reset on May 1 each year.

Prevailing Wind Direction - Polar Plot

This Radar Plot displays the most recent wind direction at the outer edge—similar to NSC’s original “Windicator.” When wind speed reaches 0, the direction is “frozen” to the last non-zero value until wind resumes.

Prevailing Wind Frequency - Polar Plot

This Wind Rose groups wind data by speed and direction into 7 speed ranges and 16 compass directions, shown as colored sectors representing frequency.

6-Hour Chart: Prevailing Wind & Peak Gust

This chart shows:

• Wind Speed and Wind Direction: 5-minute averages, updated every 5 minutes.
• Peak Gust: The highest wind speed during each 5-minute interval.

When wind drops below 1 knot, the arrow is replaced by a dot. If wind speed is 0, the wind direction is retained (“frozen”) from the last non-zero reading—unless the wind is still 0 at midnight, in which case it resets to 0° (North).

Note: These 5-minute averages differ from the 10-minute averages used in the 24-hour and 7-day plots, so wind speeds, directions, and gusts may vary between charts.

Temperature, Pressure & Humidity

These follow the same 5-minute update cycle and display recent trends over the past 6 hours.

Water Level

This chart uses hydrometric data from Environment Canada for station 02KF005 (Britannia).

Data is updated:

• Hourly (at minute 1) from April 1 to October 31
• Every 4 hours (00:01, 04:01, etc.) from November 1 to March 31

Gaps may appear when data isn’t available—resulting in flat lines—or when there’s a delay in data transmission. If the data file contains invalid entries (e.g., "99999"), the graph will display a “no data” message. When updates resume, the chart will show the past 12 hours of available data.

Disclaimer

All data is provided “AS IS” without warranty. NSC does not guarantee accuracy, completeness, or timeliness.

Suggestions or Errors?

Please contact the Weather Station Team.

Usage Notes updated on 2025-06-29.

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