PDA

View Full Version : Would you describe a 1/2 inch of rain?


Rhythmdvl
06-14-2008, 12:25 PM
I just saw a neat guarantee on Priceline. In essence, if it rains a half-inch or more during half your vacation days, they’ll refund the entire trip (if it rains a half-inch on at least four days of an eight day vacation, you qualify). I’ve never really paid attention to rainfall amounts—what does it take? I know it’s a bit hard to describe such nebulous terms as downpour or light rain, but generalities are ok. Is a three-hour downpour a half-inch? Would an eight-hour light rain typically rise to a half inch?

I assume they did some actuarial work to come up with the figure and doubt they’re going to be refunding money left and right—I just want to get some sense of what it would take.

Bonus points for answering in haiku.

Schnitte
06-14-2008, 12:36 PM
Half an inch of rain is exactly what it sounds like - the water stands at a level of half an inch on a surface exposed to rain, assuming there is no drainage. They use rain gauges (http://en.wikipedia.org/wiki/Rain_gauge) to measure this, but I think you could take just any waterproof container and put it outside.

I never did the experiment myself, so I have no experience as to which kind of downpour (and how long) it would take to reach half an inch. Looking at the precipitation chart of Chicago (http://en.wikipedia.org/wiki/Chicago%2C_Illinois#Climate) on Wiki, however, I see that the average daily amount of rain for Chicago is well above that threshold in each one of the twelve months. In contrast, even a city like Phoenix, AZ (http://en.wikipedia.org/wiki/Phoenix_Arizona#Climate) with its arid climate tops half an inch in every month except April through June, so it doesn't seem to be that much.

Rhythmdvl
06-14-2008, 12:48 PM
Oh I get what it means and how it's measured, but like you, I've never actually connected that to what's actually going on out my window. How long of a heavy downpour does it take to get to a half-inch?

Colophon
06-14-2008, 01:01 PM
Well, heavy downpours in the UK can't compete with heavy downpours in the tropics, or even in the mainland USA, but as a rule of thumb I'd say that an hour of moderately heavy rain - heavy enough to be unpleasant to go out in, but not flash-flood heavy - would yield about 5-7mm of rainfall. Half an inch of rain is just under 13mm, so 2 hours of heavy rain could give you half an inch.

Edit: just to put some figures on it, here (http://metoffice.gov.uk/weather/uk/guide/key.html#radar) is the key to the UK Met Office rainfall radar, identifying rainfall rates for different colours on the radar.

"Downpour" is anything over 16mm per hour, i.e. half an inch in 47 and a half minutes. "Heavy" rain, as I said, would be around the 5mm per hour mark.

Chessic Sense
06-14-2008, 01:09 PM
Would I describe a half of rain? Sure. It's an R and an A.

Santo Rugger
06-14-2008, 01:30 PM
<snip> Looking at the precipitation chart of Chicago (http://en.wikipedia.org/wiki/Chicago%2C_Illinois#Climate) on Wiki, however, I see that the average daily amount of rain for Chicago is well above that threshold in each one of the twelve months. In contrast, even a city like Phoenix, AZ (http://en.wikipedia.org/wiki/Phoenix_Arizona#Climate) with its arid climate tops half an inch in every month except April through June, so it doesn't seem to be that much.It seems that those are charts for a month, while the OP is talking about the amount of rain in a day.

NinetyWt
06-14-2008, 01:53 PM
Here is a chart for Chicago (http://wunderground.com/weatherstation/WXDailyHistory.asp?ID=KILCHICA26&day=14&year=2008&month=6&graphspan=month)for June 2008 (scroll down to Month Tabular Data). Note that one one day alone the rainfall was 0.54 inches.

Colophon is correct, rainfall rates vary by geographic location. It seems likely that 0.5" of rain could fall on a few days of a tropical vacation. However it might not be likely that it would occur one-half of all days.

Here's Honolulu (http://wunderground.com/weatherstation/WXDailyHistory.asp?ID=KHIHONOL8&graphspan=month&month=11&day=14&year=2007)for November of 2007. Looks like 3 days of such rainfall amounts. I imagine that Priceline is banking on the small chance of "half of your vacation days".

suranyi
06-14-2008, 02:00 PM
I just saw a neat guarantee on Priceline. In essence, if it rains a half-inch or more during half your vacation days, they’ll refund the entire trip (if it rains a half-inch on at least four days of an eight day vacation, you qualify). I’ve never really paid attention to rainfall amounts—what does it take? I know it’s a bit hard to describe such nebulous terms as downpour or light rain, but generalities are ok. Is a three-hour downpour a half-inch? Would an eight-hour light rain typically rise to a half inch?

I assume they did some actuarial work to come up with the figure and doubt they’re going to be refunding money left and right—I just want to get some sense of what it would take.

Bonus points for answering in haiku.

Geez, I should have booked something like that for my recent week-long vacation in Amsterdam. It rained EVERY day, and hailed on half of them!

Ed

CC
06-14-2008, 02:19 PM
just sayin' - you can get an idea of how much rain is 1/2 inch if you put your mind to it for a few weeks or months. Watch the weather reports on tv. Every once in a while, someone will tell you that your area got, say, .3 inches of rain. Another time, you'll hear .1 inch, or 1.4 inches. Over a period of a few weeks of weather, you'll get a generalized sense - in your own personal terms - of what that actually means. It's moderately accurate, but just not very precise.

Xema
06-14-2008, 02:23 PM
I just saw a neat guarantee on Priceline. In essence, if it rains a half-inch or more during half your vacation days, they’ll refund the entire trip (if it rains a half-inch on at least four days of an eight day vacation, you qualify).
Something tells me they won't be extending this guarantee to Milford Sound (http://en.wikipedia.org/wiki/Milford_Sound) (scroll down a bit to see rainfall amounts). Half the days there have rain; with an average amount being 37mm (1.45").

Schnitte
06-14-2008, 02:29 PM
It seems that those are charts for a month, while the OP is talking about the amount of rain in a day.

Geez, you're right. Goes to show I really, really never did the experiment on my own, but I could make up for that. Right now, however, it doesn't look as if it were going to rain tonight.

Bootis
06-15-2008, 01:09 AM
We just has some storms pass through Missouri that dumped about an inch of rain each. It was pretty heavy rain, though not uniquely excessive. The storms lasted about an hour each. I also know that your typical "rainy day " where it rains all day, sometimes heavy, usually light and steady, sometimes will result in up to and inch of rain, and usually more than a half inch.
Fow what its worth, on average, a snowfall that results in 5 inches of snow is equivalent to 1/2" of rain.

Tapioca Dextrin
06-15-2008, 01:17 AM
Half an inch of rain
Measured in a cup
Would be a really wet day

Quercus
06-16-2008, 08:51 AM
2 hours of heavy rain could give you half an inch.Depending on what you mean by 'heavy', this might be a trifle longer than necessary. I think most people in the eastern US wouldn't describe a quarter inch as hour as particularly 'heavy'. That would be more like a normal unremarkable rainstorm. If you hear anyone remarking on how hard it's raining, then it's more than a quarter inch an hour.

Or, to put it another way, and get to the bottom line of the OP, if you describe the day as anything more than 'some light showers', it's probably over half an inch of rainfall.

Ludovic
06-16-2008, 08:57 AM
Or, to put it another way, and get to the bottom line of the OP, if you describe the day as anything more than 'some light showers', it's probably over half an inch of rainfall.I'd agree to that. In fact, if it rained the whole day hard enough that you'd have to worry about getting wet when you walk to your car it would probably be more than a half inch.

One hour of moderately heavy rain would probably be around a half inch. ("Moderately heavy" in Florida terms, that is. I've seen stuff that I swear was an inch in what seemed like only a few minutes.)

Paul in Qatar
06-16-2008, 09:04 AM
A major event, flooding across city streets, people out driving and walking to see the rain, people posing for photographs.

RickJay
06-16-2008, 10:08 AM
Half an inch of rain is a LOT of rain. That is a very substantial rainfall.

The likelihood of getting half an inch of rain of half the days of any given vacation is very, very small.

I did some research. In Toronto, which is famous for having wet summers, the average rainfall in summer is about 7mm, or roughly a quarter of an inch, and happens one in every three days. The likelihood of getting four double-heavy rainfalls in eight days is... well, it would be pretty unusual.

lieu
06-16-2008, 10:25 AM
Of course responses to your question will be entirely subjective, but I'll try. In my mind, it takes at least 1/10 of an inch of rain before it even seems to appear to reach a point where it'll do anything besides the grass any good. Once you've hit 1/10 though, you're likely to acknowledge that what's happened so far is worthwhile.

Unless you live in the tropics or someplace prone to moonsoons, if you get 2 to 4 inches you've had one heck of a good soaking. This would be a multi-hour, sometimes pouring, toad strangler.

For 1/2 an inch then, it'll probably take a medium downpour for about an hour or so. Maybe that long for it to come on, build to where it's pretty loud inside even, and then taper off.

I'd agree with RickJay wrt to the offer. 1/2 a day for 50% of a given period, while not impossible, will be unusual outside of India, Hawaii and other places where it's a noted and expected aberration.

MikeS
06-16-2008, 10:38 AM
If you're in the States, you can look up your weather history at the following site:

http://wunderground.com/history/airport/KMDW/2008/6/16/MonthlyHistory.html#calendar

Just replace "MDW" in the URL with whatever the code is for your closest airport (ORD, LAX, BOS, etc.) and take a look. Note that this reports rainfall in centimetres, not inches, so the criterion is "more than 1.27 cm of rain."

Doing this for my local airport (MDW) reveals that we've had three days since the beginning of the month with more than a half-inch of rain. However, it's been an unusually wet June here in the Midwest (as you might have heard.)

mwbrooks
06-16-2008, 01:50 PM
Austin got 5.5 inches in one hour once. That was pretty impressive. Unfortunately 13 people died in the floods.

Thrall, not far from here, got 38 inches in 24 hours once, of which 32 inches fell in 12 hours. Sometimes a thunderstorm just rears up and rains itself out in one spot.

1/2 inch around here could be a nice rain, or scary, depending on how fast it's falling. You can stand in the sunshine some days, look around the horizon, and see streams of rain falling from the clouds here and there, like water from a firehose, but the official rain recorded for the day is zero. I swear, once I avoided a downpour by changing lanes.

Best Topics: carved quartz nynaeve pronunciation rotten carrots rammstein amerkia heinz 51 reddit nbsfw desmond harrington crazy drank sour milk bob gray lowes code 3 greatschools.org ny vietnam officers aztec history books lasko fan ionizer sybil gooley dryer delicate choking on ice cartilage healing time clipping football penalty bruce lee lats canine latin herbivore pronunciation ms vs ma ghost world meaning house teardrop mens arm garters vaccine mark injectable sedative retarded kid helmet man size tissues overseas courier jobs when are radishes ready to pick how to pronounce niche penny arcade archive by date smart roadster coupe for sale usa ferber method for naps what is ed d stainless steel ring resize change smoke detector battery high ceiling touch of gray for beards how to get a prescription for steroids p1739 honda odyssey 2000 leg of lamb alton brown value of a gold quarter jamie foxx bacon number does a cash register do the math for you two alarm fire definition do cats personality change after spaying hobo sack on a stick my car squeals when i turn it on miniature poodle terrier mix do no soliciting signs work is hydrogen a metal or nonmetal why can't you say macbeth in the theater in the same vein origin lump in scrotum that moves does tourettes make you swear why do my armpits itch so much what does simple mean seasoning salt vs salt jump his bones meaning why does cracking knuckles feel so good according to his business card, what did al capone do for a living sandra farrow gg allin skin flaps in mouth is liver good for dogs can rabbits and cats breed under armour coldgear infrared review