Cumulus Support

I seem to have an issue on my rainfall gauge, with "natural" rain the highest rainfall rate I seem to achieve is 3.6mm/hr. Taking a spray bottle and simulating a heavy rainfall gives higher readings.

Any suggestions?

Presumably you haven't had heavy enough rain to trigger higher rain rates. The rain rate calculation is fairly primitive (Cumulus has to do it because Fine Offset stations don't), it uses the amount of rain in the last 5 minutes. 3.6mm/hr is one tip in 5 minutes. To get a rate >3.6mm/hr you need at least two rain tips (of 0.3mm each) in 5 minutes.

Hi Semmy

My heaviest was 39.6mm/hr so it does count greater figures!

http://www.grantownweather.co.uk/records.php

I can't do the maths (as it is late) on how many tips that is in a minute, but I do know it was raining really heavily

I too have had higher figures when we've had heavy rain.