Detect and ignore data spikes

[loser]

I've got a column of water temperatures, every minute for a month. 44640 points of data for a 31 day month.

Times six systems, times several years.

I need to know the maximum temperature achieved during the month for each system.

I'll do this on a month by month basis.

But wait, it isn't that simple.

Occasionally a valve will open and a different cooling pump kicks on, causing a one to three minute temperature spike.

Since these are not normal/typical conditions, I would like to ignore these anomalies.

The initial average temperature might be 60F, then after the brief spike the average temperature might be 40F.

These temperatures vary, and the degree of the spike varies. Might be 120F or only 80F.

So I can't simply tell it to ignore data that is a percentage higher than average.

What method can I use to get Excel to detect and ignore the spike, so it doesn't get counted as the maximum temperature?

[teylyn]

Hello,

could you upload a small data sample in a workbook, so we can see how your data is laid out? Make sure to include some spike data and maybe define a threshold for spikes.

cheers,