Unexplained temp spikes

I’m having problems with spikes showing up in my temperature graph. The spikes mins and maxes are also being recorded in WD for my daily, monthly, yearly averages and extremes etc. I never used to have this problem, then it started happening occasionally, and now I am having frequent problems with this. It some times (but not always) seems to fix it when I reboot the system. So I think it’s got something to do with the computer or software, and not the station it’s self. I am using the computer for some other things too such as running a web browser, email and dreamweaver etc. I am running WD version 10.37N. Has anyone got any ideas?

This image shows the spikes in the graph and the resulting incorrect min/max temperatures.

  • bump *

Really has no one else had this problem? I’m seeing what seems to be causing the problem in the log files. When a spike appears, a “0” is put infront of the temperature as in the following spike example;

11 3 2009 10 30 09.9 100 09.9 1021.8 4 5 235 0.0 0.0 32.7 265.4 9.9
11 3 2009 10 31 010.0 100 010.0 1021.8 3 5 235 0.0 0.0 32.7 265.4 10.0 - spike
11 3 2009 10 32 10.0 100 10.0 1022.0 3 5 235 0.0 0.0 32.7 265.4 10.0

It looks like the problem is in WD!

No temperature problems here.

Yes, I’ve seen that many many times in mine but never associated it with spikes on the graph, I’ll have to go back and look. I’ve just been fixing it when I see them!

I also get them repeatedly at temp changes from 9.9

What temp value do you see when you move the mouse over the spike?

Just checked my graphs today and I have a huge grouping of Heat index of 5305.2F when the outdoor temperature was about 3F. Now thats a Heat Index!!

Looking at the log files, I don’t see any of that, everything looks normal. Any ideas on how to recreate the last 24 hours graphs? Maybe that will get rid of it?


You need to lower your temp scale on the graph…when the temp drops below the bottom graph scale you will see those “spikes”.

I thought it auto adjusted?

It defaults to auto adjust, but there are scale settings, maybe something has gotten set by accident? Control Panel, Graphs. Scales.

a 0 in front of a number in the logfile is not a problem
its the same value as if the 0 was not there
its just a formating issue when it goes from 9 to 10
its not a data spike, and will not be coinciding with the data spikes

the data spikes you see will be unique to the WH1081 station

you could try clearing out the memory buffer on the station

Thanks for all the replies! I think it was just coincidence that the spike was around the same time as the leading “0” thing. I am seeing spikes else where with real values in the logs. I think you might be right Windy, about it being the station. I’ve reset the memory now so I’ll see how that goes.

As Niko says, it defaults to auto-adjust but that can be overridden with manual settings. And I don’t know if it will adjust auto for anything besides rain and air temp and baro. I know I have had to adjust mine for dewpoint in the past…

I think you are correct, I did find the section that lets me manually change it, that cleared it out. Perhaps this is something that Brian can add into the auto scale? It wouldn’t be much of an issue except for the fact that it does export the graphs that way as well.


which version of WD (build) are you using 35mm?
as there was a problem, but should have been fixed, with spikes like that from the WH1081 station


I have problems with spikes too. Almost daily, once or more times.

See example.



i see you have a WS2010 type station
so your particular problem is different to the problem with the WH1081 station

The WS2010 is not an easy data logger to support

which version of WD?

It’s the newest one, 10.37N Build 20.


I’ve got similar spikes very sometimes with a WMR200, they usually happen after I had the computer off for a while and restart it (that’s just an observation but it might have nothing to do with it).