meteohub.de

I have setup an Individual HTTP Upload (in push services), to happen every hour.
So I would expect that the Meteoridge would send a request every hour, every day, with a constant time offset.

But it's not the case, see how the timing of the upload event slowly drifts :
25/11/2013 20:13 2.5 9.1
...
26/11/2013 02:13 -0.4 8.8
26/11/2013 03:14 -0.3 8.8
...
26/11/2013 16:14 4.5 8.8
...
27/11/2013 00:15 -0.8 8.3
And so on. The hours and minutes rerported are from the system time of the meteobridge, and the drift is identical
if I read the time on the receiving server.

This makes it impossible to draw proper graphs of the data sent.

Your expectation that "every hour" does match the exact a start of an hour or exactly 3600 seconds is simply false. Data uploads are triggered when new data comes in and that might not exactly match the 3600 seconds spend til last upload.

I would recommend to upload every few minutes and let your CGI script just store the first occurence after the hour has changed.