Author Topic: WXDailyHistory.asp, temperature discrepancies, graphspan  (Read 1038 times)

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Offline NanoWx

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WXDailyHistory.asp, temperature discrepancies, graphspan
« on: March 06, 2017, 10:31:16 PM »
The graphspan parameter defaults to current month, summary for each day. The temperature maximum (Tmax) from that is sometimes not in the detailed data from graphspan=day. When spot checked for my own pws, the summary Tmax did agree with what my weather base station had internally.
That suggests wunderground may have an undocumented (as far as I've found) API feature to pull Tmax from a pws (Tmax_stn).  Yet, for the minimum temperature (Tmin), wunderground appears to only use what is in the detailed data from graphspan=day. I've seen instances when Tmin_stn was lower than Tmin available using WxDailyHistory.php (either graphspan default, or graphspan=day).
The difference is often only a few tenths of a degF, but it could introduce an upward bias to temperatures, in the aggregate.