Weekly Averages for Llanrhystud : July 1 – 7 2018

Average daytime high: 73°F
July average daytime high: 67°F
Average night time low: 64°F
July average night time low: 53°F
Total rainfall: 0.002 inches
July average rainfall (per week): 0.625 inches
Average windspeed: 0.45mph

Summary: Heatwave conditions are still with us and looking at the forecast will remain with us for the whole of next week before breaking around next Tuesday, meaning that this heatwave will have lasted no less than 23 days.

3 thoughts on “Weekly Averages for Llanrhystud : July 1 – 7 2018”

  1. Thanks for your great weekly report Harry. Gosh the term “heatwave” is really “relative” – an average weekly high of 73 in early July would be a “cool-wave” or described as “fall-like” in my area. In areas like Death Valley is always hot, and they would need an average weekly high of 120° or above to be in a “heatwave” in that special part of the world.
    How did you read 0.002″ of rainfall. In looking at your gauge, I believe the scale along the side is in hundredths, not thousandths – and normal reporting units are to the nearest hundredth. When you get into amounts less than 0.01″ if you can tell that the amount is at or over half the distance from the bottom to the 0.01″ line than that would be reported as 0.01″. If under half, it would be reported as a trace.
    Now complicating things are if your rain gauge is incremented in millimeters and you are converting to inches, that is a different story. We can go into that if that is the case.
    The precision of all our instruments is expressed in the paperwork for the instrument among the whole package. Carrying extra decimal places gives others a false sense of accuracy, over and above the accuracy of the instrument. For averages, tenths of a degree is the limit for reporting temperatures (I notice you gave temps in whole degrees, which is still fine if you stay consistent with that), hundredths of an inch for rainfall (rounding 5’s up normally), and at most tenths of a MPH or KM/HOUR for average wind speeds.
    For daily reports, remember to try to report the temperature at observation time, and the sky condition at that time also. I look forward to seeing more of your daily reports in the coming days.
    Thanks again for posting your most interesting climate statistics for your piece of the world. Cheerio, Kevin

  2. The measurement of the rain (which fell on July 2nd by the way) was estimated as being 0.05mm (based on the mm scale) which starts off at one mm and was then converted into inches (for the simple reason as the only non American here, common courtesy says “Adopt what everyone else is doing” so therefore although all measurements are in °C, mm and mph, they are converted into °F, inches and mph for the convivence of readers.

  3. Hi Harry! Are you sure you estimated 0.05 mm. It is very tough to conceptualize that you could estimate that small an amount. I could believe 0.5 mm, but 0.05 mm is a bit too small to get any sort of estimate, IMHO. In the US, if you actually can read in thousandths of a second, or hundredths of a mm, amounts of 0.004″ or 0.05 mm or less would be expressed as a trace amount. Above those values but still less than 0.01″ or 0.1 mm would be rounded up to 0.01″ or 0.1 mm. I have a query into one of our cocorahs headquarters precipitation experts about this question and will relay his findings here. cocorahs is a nationwide precipitation reporting database, piped into many researchers and our NWS to get a pulse on the daily rainfall (and snowfall and snow depth in the winter) amounts. If you can get your internet to hook up with https://www.cocorahs.org you can view/read/download the extensive data included. I have contributed my daily rainfall every day since October 2005, with some glitches in the record around the time I moved at the end of 2016 and beginning of 2017. Thanks, have a great day. Cheerio, Kevin

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