Welcome to the new home of the Cumulus Support forum.

Latest Cumulus release v1.9.4 (build 1099) - Nov 28 2014
Latest Cumulus MX release - v3.0.0 build 3043 Jan 20 2017. See the Wiki for download

Longest Dry Run curiosity

Discussion and questions about Cumulus weather station software version 1. This section and its subforums are the main place to get help with Cumulus. Anything which is not specific to the type of weather station goes in here; for anything specific to a type of weather station, please use the appropriate subforum. Use the 'website development' section for any questions relating to creating or running a web site for Cumulus data. Discussion of the stations themselves in these sections is fine.
Post Reply
patchpeek
Posts: 3
Joined: Sat 23 Jul 2011 9:52 am
Weather Station: Maplin N96GY
Operating System: win 10 pro
Location: England

Longest Dry Run curiosity

Post by patchpeek » Thu 26 Jul 2018 4:58 pm

My Cumulus "Longest Dry Period" ended at 31 days, when we had 0.6mm on the 21st July. However whilst listening to a BBC weather man on Radio 4 talk about some areas experiencing 45+ days continuious days of no rain, he said that rain less than 1mm does not officially count! I was very suprised. Did i hear that right ? I would be on 46 days if the brief shower was excluded....

This seems to suggest,if true, that the Cumulus Software defintion of "Dry Run" or the default "RainDayThreshold" might not be quite right perhaps.

This is not a complaint and I don't have an issue; it works as I expect and want. Perhaps you are aware or not, either way, I just thought I would throw this up here out of curiosity.

Best Wishes.

pp

User avatar
steve
Cumulus Author
Posts: 26714
Joined: Mon 02 Jun 2008 6:49 pm
Weather Station: None
Operating System: None
Location: Vienne, France
Contact:

Re: Longest Dry Run curiosity

Post by steve » Thu 26 Jul 2018 6:09 pm

I'm pretty sure that the Cumulus default of 0.2mm corresponds to the official definition of a dry day as defined by the Met Office and/or the WMO, or at least it did at the time I wrote the code. See this page, for example: https://www.metoffice.gov.uk/climatecha ... daily.html

Perhaps the definition has changed. But 1mm is quite a lot of rain, I don't think I would regard that as a dry day myself.
Steve

User avatar
dazza1223
Posts: 414
Joined: Sun 25 Jan 2015 8:41 pm
Weather Station: Davis Vantage Vue
Operating System: raspberry pi 3 +
Location: worthing
Contact:

Re: Longest Dry Run curiosity

Post by dazza1223 » Thu 26 Jul 2018 7:08 pm

note just me then have the same thing min say 12 off may last time we hade rain but it saying Days Since Last Dry Day 44 Days but it ment to be over 60 days now
have fun and keep learning

dazza :D

User avatar
steve
Cumulus Author
Posts: 26714
Joined: Mon 02 Jun 2008 6:49 pm
Weather Station: None
Operating System: None
Location: Vienne, France
Contact:

Re: Longest Dry Run curiosity

Post by steve » Thu 26 Jul 2018 7:12 pm

dazza1223 wrote:note just me then have the same thing min say 12 off may last time we hade rain but it saying Days Since Last Dry Day 44 Days but it ment to be over 60 days now
This is nothing whatsoever to do with that.
Steve

RayProudfoot
Posts: 2620
Joined: Wed 06 May 2009 6:29 pm
Weather Station: Davis VP2 with Daytime FARS
Operating System: Windows XP SP3
Location: Cheadle Hulme, Cheshire, England
Contact:

Re: Longest Dry Run curiosity

Post by RayProudfoot » Thu 26 Jul 2018 7:18 pm

steve wrote:But 1mm is quite a lot of rain, I don't think I would regard that as a dry day myself.
I agree. That's 0.04" in old money. I set the trigger at 0.01" as I can get quite a few days with dew recorded.
Cheers,
Ray, Cheshire.

Image

User avatar
dazza1223
Posts: 414
Joined: Sun 25 Jan 2015 8:41 pm
Weather Station: Davis Vantage Vue
Operating System: raspberry pi 3 +
Location: worthing
Contact:

Re: Longest Dry Run curiosity

Post by dazza1223 » Thu 26 Jul 2018 7:18 pm

o sorry my bad i just re read it sorry steve
have fun and keep learning

dazza :D

Post Reply