Incorrect Rain fall readings and their (Strange) causes!

[Gazzadp]

Firstly I hope the sites creator and the admin won't mind me starting this thread, but as a beginner to monitoring the weather using a more than just looking at a barometer. I thought this thread might well end up with a light hearted and humorous look at some of stranger reasons for the incorrect rain fall readings that some of us will have from time to time.

Anyway on Saturday evening I noticed that according to my F01080 (and Cumlus) we had 4.9mm of rain!

The only thing was it was relatively clear and cold.

Then it twigged, the cause for this was in fact my little terrier and the next door neighbours dog having a heated discussion at the fence. You see the sensors for my weather station are mounted on an approx 10 metal pole, firmly fixed to the close panel fence post, which is set in concrete. So I can only assume that when the dogs were going at it hammer and tong, the vibrations caused the rain meter to think it was raining!

Anyway I still love my little dog, even if he is a pain in the....

Best Wishes

Garry

PS: Many Thanks for a really great bit of software!

[gappell]

I have had similar problems with daily rainfall amounts of 0.3 mm when we have clear sky. I have not been able to find the cause.

I would like an addition to the calibration menu to include an offset or spike removal for erroneous rainfall. This would correct any small negligible amounts. Perhaps Steve could add that to any future updates.

Jerry

[mcrossley]

I don't see how Cumulus could possibly differentiate between an erroneous tip and a real one? It already has spike filters for excessively large rain amounts.

[steve]

Perhaps he means a setting to ignore the first tip of the day (or some other configurable amount) to allow for dew etc, as in a recent enhancement request?

[mcrossley]

Does that mean literally ignore the first tip, or ignore the first tip unless there is a subsequent one (within an hour say)?

[steve]

As far as the enhancement request is concerned, that seems to be to ignore the configured amount unconditionally.

https://cumulus.hosiene.co.uk/tracker.php?p=1&t=204

[gappell]

Yes, I guess I am asking to add an offset such that these small readings caused by a single tip or several tips could be ignored.

Thanks for your consideration.

Jerry

[Gordon-Loomberah]

I don't often venture into the Fine Offset section, due to owning a Davis but this morning the rain was flogging down and I was looking at the rate staying fairly steady at under 5mm/hr. I knew that certainly wasn't right, so ventured out into the rain to check the problem.
It seems some spider web had caught a few Scotch Thistle seeds and the lot had washed down into the funnel, seriously restricting the flow. Once I poked it with some grass, the half-full collector rapidly emptied and I could hear the buckets tipping merrily away, to produce a rate of 1718mm/hr! I probably lost some of the rain, as I doubt the tipping bucket mechanism was designed to operate at that sort of speed, so there would probably have been some splashing out from the buckets. I've edited out all mention of the new "record rainfall rate", although the spike is still there in the graphs.

[captzero]

Once I poked it with some grass, the half-full collector rapidly emptied and I could hear the buckets tipping merrily away, to produce a rate of 1718mm/hr!

Would have sounded like a machine gun

[FrostyJW]

I had a similar problem over a 2 month period, where there was no rain readings at all (always zero) despite some heavy rain. I found a spider had got inside the rain gauge mechanism that was stopping the "see saw" mechanism from working - the web had entangled in the interior. Cleaning it out cured the problem.

John W B'ham UK

[steelblue48310]

I noticed that my mast was shaking in the wind, causing erroneous 'tipping'. I moved the rain bucket to a much lower position on the mast, and it is much more accurate.