The default station chart contains Temperature, Dew Point Temperature, and Relative Humidity. If a station has not reported any of those elements during the requested period, no chart will be available.

The chart has a limitation where 1000 data points per element can be displayed. For longer duration datasets, with multiple reports per hour, this will exceed the charting capability. Therefore, data will be trimmed when it exceeds 1000 datapoints, and will then display every 2nd, 3rd, etc point. If you require high resolution charts, the "Historical Data" option will be helpful.

• Example 1: A NWS ASOS reports 12 - 13 times an hour. After 76 hours, data will be trimmed in the chart.
• Example 2: A station that reports 4 times an hour will begin trimming data after 250 hours.

To view charts for additional elements, using a mouse, move the cursor over the element headings. If a "magnifying glass" cursor appears, it means that if you click on that heading, data for that element will load into the chart. See image below.

The following weather elements are available for viewing in a chart. Note: Data availability varies by station.

Clicking the "Settings" icon will open an area where you can select different viewing parameters.

• Units of measurement: toggle between "standard (with speeds in mph)", "standard (with speeds in knots)" and "metric" measurements.
• Number of hours: Up to 720 hours (30 days) of data can be displayed on this page.
• Page Headers: Select how much of the "top" of the page you'd like to see.
• See Chart: Toggle "on" or "off" the data chart
• Gather Historical Data: When "On" is checked, you will be able to select the starting and ending dates you are interested in getting data for (limit of 30 days)
• Observation Type: The page will display coded Meteorological Aerodrome Reports (METAR), and Special Reports (SPECI). See how to decode METARs here
• Hourly Data: By default, the page will display all data for a given time period. If "Yes" is checked, the page will only display data where the observation time stamp has between "51" and "59" in the minutes field for NWS/FAA observation platforms (to include any "SPECI" observations/data - with the date&time stamp highlighted in yellow), and between "56" and "04" for all other platforms.
  • If the station is a federally owned ASOS/AWOS, METAR and SPECI data will be included.
  • SPECI data will have a bold timestamp and be highlighted in yellow. See image below.
• Precip View: This will select how the calculated precipitation values fill in 1, 3, 6, and 24 hour fields in a row of data.
  • "Full" will populate out each row with 1, 3, 6, and 24 hour data. Note: This takes longer to load.
  • "Standard" will populate lines rows are aligned with times corresponding to 1, 3, 6, and 24 hour data
  • "Measured" will NOT populate 1, 3, 6, and 24 hour data. This will simply display the value reported by the sensor.
• Apply Settings: When you click this button, the page will refresh with the options you selected. The URL in the web browser address bar has those options "built in", so the format can be saved/bookmarked.

How Clouds are Measured

Cloud height sensors can measure clouds up to 12,000 feet above the ground, when the cloud is directly above the sensor.

This limitation can result in "Clear" conditions being reported, when clouds are above 12,000 feet.

At major airports, this information can be augmented by a trained observer, who can also determine heights greater than 12,000 feet.

Decoding Cloud Information:

• Up to 3 layers (the lowest 3 layers) of clouds can be reported.
• The first 3 letters of a cloud group describe the amount of sky coverage. The last 3 numbers indicate the base of that layer, above the ground x 100 feet.
• SKC: Sky Clear.
• CLR: No clouds below 12,000 feet above ground level, as detected by automatic equipment.
• FEW: Few Clouds - Between 1/8 and 2/8 of the sky is covered by clouds.
• SCT: Scattered Clouds - Between 3/8 and 4/8 of the sky is covered by clouds.
• BKN: Broken Clouds - Between 5/8 and 7/8 of the sky is covered by clouds.
• OVC: Overcast - 8/8 of the sky is covered by clouds.
• VV: Vertical Visibility - An indefinite cloud ceiling caused by fog, rain, snow, etc.

Precipitation (precip) can be measured 2 different ways: Using a weighing mechanism, or by using a tipper.

• When a weighing mechanism is used, precipitation (rain, or snow) will be stored in a bucket, and an electronic scale is used to convert the weight to a value. Accumulated Precipitation is reported.
• When a tipper is used, liquid precipitation (rain or melted snow) gathers in a small measuring cup that looks like a see-saw. Each time it fills up, the see-saw tips, and that action is recorded as 0.01 inches of precipitation. The number of tips over the recording period results in the value displayed.

Precipitation is reported in 5, 10, 15, 30, or 1 hour increments. Values for 3, 6, or 24 hour precipitation are extrapolated from those reports, and are displayed hourly, or every 3, 6, or 12 hours (for 24 hour precip).

If a station reports precipitation, the "top line" of data will always include precip over the last 1, 3, 6, and 24 hours, relative to that time.

Snow depth is generally measured by probes mounted above a surface. They measure the distance between the probe and a surface. As snow accumulates or melts/blows away, that measurement will change.

"Snowfall" calculations are made by taking the snow depth measurement at a given time, and subtracting the snow depth from 3, 6, or 24 hours previous to time the current snow depth value was recorded. Negative values are not recorded.

If a station reports snow depth, the "top line" of data will always include snowfall over the last 1, 3, 6, and 24 hours, relative to that time.

Data can be downloaded by clicking the 3 lines in hte upper right corner of the chart, and clicking "Download CSV or Download XLS"

Please provide feedback, or report issues with this page by sending email to wr.web.support@noaa.gov

If you're reporting an issue, it's helpful if you:

• Include the URL you're noticing the issue with
• Include the link from the page that "got you to" the URL above
• Include a screen shot for display/graphical issues, if you can

Current Known Issues:

• Hourly charts sometimes display "non-hourly" data

Things We Are Exploring:

• Issuing a cookie to preserve settings
• Selecting certain charts to load by default
• Selecting certain chart elements NOT be displayed on page refresh
• Freezing the table header at the top of the page when scrolling