Cumulus Support

Can somebody tell me if there is an average rain rate function?

Observing my gauges, the rain rate changes with each recorded bucket tip, but then drops to zero (normally during slow rain rates) whilst waiting for another tip of bucket - even though it is clearly still raining. So I was wondering if there is a short average rain rate feature (a bit like the 10 min. average wind speed). If this was available, I could then (attempt to!) add a needle to my rain rate gauge, giving remote observers a better indication as to the current conditions.

I hope this makes sense and thank you in advance for your assistance in this matter....

The (very simple) rain rate calculation that Cumulus does for Fine Offset stations is already an average, it's the average over the previous 5 minutes. There's no option to change this interval. I hope to (re)introduce a more advanced rain rate calculation at some point which is based on the calculation that Davis stations do; see other recent posts about this. The Davis calculation returns to zero when there hasn't been a tip for 15 minutes.

It's quite difficult to produce sensible rain rate figures from tipping-bucket rain gauges, particularly if the rain is light.

Thanks for the input steve -I appreciate this is a tricky parameter.

Your reply however raises another point - is Cumulus calculating my rain rate correctly? Surely if it is correct, it would not drop immediately down to zero after registering my latest rain rate, being a 5 min average after all. I will have to study this in a little more depth.

It should drop to zero about 5 minutes after your last rain tip. From your graphs it looks like your tips are slightly more than 5 minutes apart, which is why it keeps dropping to zero. But it's hard to say just from the graphs. But between 10:00 and 12:00 you had about 5 mm of rain which is about 16 tips, so that's an average of about 7.5 minutes between tips, so that fits with your rain rate graph.