Author Topic: Weather Data Update Time Delays  (Read 145 times)

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Offline havtrail

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    • Haverford Weather Station
Weather Data Update Time Delays
« on: September 01, 2018, 03:32:07 PM »
I spent some time today carefully documenting how current my station's info is on Weather Underground, as well as its home HOBOlink page, even under the best conditions. Here's a spreadsheet summary, followed by comments:

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Each 3-row group in the spreadsheet consists of (first) the time that the HOBO weather monitoring station completed its cellular upload to the HOBOlink server, as documented on the station’s HOBOlink home page under the “Log” tab. After that row follow the times (as shown on my internet-synched Windows screen) when the HOBOlink dashboard or station home page automatically updated itself, and when the Weather Underground PWS page for the station automatically updated itself. (I also monitored the WU Flash-based widget updating, with the surprising result that sometimes it updated before the WU PWS page did.)

Each upload consists of data from two timepoints at 5 minute intervals. For some reason, the HOBO system waited about ten minutes between data logging and uploading. That made the data being uploaded already 16 and 11 minutes old, respectively, at the time of upload, instead of being uploaded while it is still fresher.

WU uses and saves only the first (and therefore the older) set instead of the second, more recent set. This adds a 5 minute delay to the data that WU displays. HOBOlink uses the second, more recent set.

Weather Underground
1. WU does not time-stamp its data display. Instead it shows “Station reported x minutes ago.” As my spreadsheet shows, less than “1 minute ago” actually means in my case data that is already 16 minutes old, so the WU display is misleading. Note that the spreadsheet shows one missed WU update, which happens to me quite regularly. (My method to time-stamp the WU data was to move my cursor back over the temperature line graph on HOBOlink until I found the most-recent reading that matched WU’s rounded value. Interestingly, it appears that HOBOlink rounds 0.5 downward instead of upward.)

2. While WU does count how many minutes have lapsed since the last update, the spreadsheet shows that the age of the displayed data actually ranges from 16 to 29 minutes out-of-date (as opposed to the lower update time displayed). The missed update caused that data display to go up to 37 minutes out-of-date (shown as “reported 20 minutes ago”).

HOBOlink
1. Despite using the more-recent set of data, the HOBOlink data display is not that much more up-to-date than the WU one. The spreadsheet shows that it displayed data from 12 to 14 minutes ago, instead of displaying the just-uploaded data from 2 to 4 minutes ago. That adds a 10 minute delay to the data being displayed on HOBOlink.

2. The displayed HOBOlink data stays displayed until the next auto-update, about every 10 minutes. The spreadsheet shows that the data being displayed ranged from 12 to 24 minutes out-of-date, and averaged from 17.5 to 19 minutes out-of-date. The average amount out-of-date was between 22.5 and 24 minutes, with the missed update period averaging 26.5 minutes out-of-date.

3. I let the pages auto-update, because that is how they will normally be viewed. I did discover that on HOBOlink I could manually click on the browser refresh button and the newer info would be displayed sooner than if I left it to auto-update. I find that strange.

Rich K.
« Last Edit: September 01, 2018, 03:40:09 PM by havtrail »
Onset HOBO RX3003 Cellular
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Offline WSWeather

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Re: Weather Data Update Time Delays
« Reply #1 on: September 01, 2018, 05:13:12 PM »
I use Cumulus to upload to WU every 5 minutes, same as I have it updating my website, and the worst it gets behind realtime is 5-6 minutes as you'd expect.  I have the Flash weather sticker on the webpage along with the direct-loaded data and they are almost never different.

For once, your issue may not be WUs fault.

 

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