In the course of planning a rather significant event for the coming weekend, I was forced, for the first time in my life, to confront the following conundrum:
- Which is sunnier — “partly sunny” or “partly cloudy”?
My faith in the power of pure reason was severely shaken when I realized I could construct equally plausible arguments in either direction. So, with reluctance, I abandoned theory and turned to evidence, in the form of the logos employed by two of the more popular weather forecasting sites:
|
Weather Underground |
Accuweather | |
| Partly Sunny |  |
 |
| Partly Cloudy |  |
 |
Weather Underground takes an unambiguous stand: partly cloudy is definitely sunnier than partly sunny. Accuweather is a little, umm, hazier on the issue; apparently at Accuweather, partly cloudy means something like “somewhat wispier clouds, covering more of the central portion of the sun but a bit less of the edges, than partly sunny”. Overall, though, it appears that at Accuweather, partly sunny is sunnier than partly cloudy.
I turned to The Weather Channel to break the tie, but as far as I can tell (after checking ten-day forecasts for a half dozen cities), the melancholy folks at The Weather Channel are quite incapable of ever seeing the world as “partly sunny”. “Partly cloudy” they use with reckless abandon.
I invite commenters to weigh in both descriptively and prescriptively on this issue—what do “partly sunny” and “partly cloudy” usually mean in practice, and what ought they mean? If we succeed in resolving the matter, we can tackle the even more difficult question:
- Which is colder — “cold” or “rather cold”?
I don’t know if “cold” is colder than “rather cold”, but I had an English teacher who liked to sneer that works which were beneath his taste were “very average”. He was unable to clarify for me how that compared to “slightly average” or “moderately average”.
“Partly cloudy” obviously (sic) means that the day will be generally sunny, but there will be times when there is cloud about. “Partly sunny”, on the other hand, means that although the day will generally be cloudy, there will be times when the clouds clear and the sun shines through.
In England, “rather cold” is an ironic term meaning “bloody freezing” generally used when describing your recent Antarctic trek or similar jaunt; just as “rather warm” means “I think my thermometer just melted”.
The UK met office seems to only use “partly cloudy”, “mostly cloudy”, “sunny intervals” “sunny” or “volcanic ashy” (except the last one).
According to this
http://wiki.wunderground.com/index.php/Educational_-_Partly_cloudy
“partly” means less than half the time. Partly cloudy is sunnier than partly sunny.
Given the ease of confusion, I think at least one should be dropped. “Sunny intervals” perhaps could be used more widely instead of “partly sunny”
This is the type of measurement question that got me hooked on the field. While this example is fun and light, what about the difference between, say, “partly competent” and “partly incompetent” or “partly complete” and “partly incomplete?” These are terms that can have tangible impact on a person’s career or fulfillment of a contract.
Are both equally far from the end of the {whatever}scale? Or does the positive end of the scale (e.g., complete or competent) require more to reach it? If so, then partly complete might be 60% complete, but partly incomplete could be only 10% incomplete. Or maybe one of the pair of apparently symmetrical terms covers a wider range of values than the other. Partly complete might cover 10% – 70% complete, but partly incomplete only 5% – 30% incomplete.
The most common application of these interpretations is in Likert Scale questions (e.g., Always, Often, Sometimes, Never). People creating the survey may attach very different numeric meaning to those terms than the people responding. This is a problem with “Rate on a scale of 1 to 4” questions, too, but that’s going too far astray from your original topic.
I seem to be in the minority (already!) but my gut feeling is that a “partly xxxx” day is a variety of an “xxxx” day. So, e.g., a “partly sunny” day is basically “sunny”, and would, generally, be a brighter day than a “partly cloudy” day. Most of the time.
One minute of Googling provided a handful of answers, each with its own degree of merit and authority. I invite you to try giving the internet a whirl.
I’m also puzzled by predictions of various probabilities of precipitation. They are open to more than one interpetation, none of much practical guidance.
Here is a link to an official-looking NWS site that has these terms organized in a chart: http://pajk.arh.noaa.gov/wxterms.php Notice that it is of no help at all in answering your question.
NOAA gives the exact same definition for both terms (“between 3/8 and 5/8 of the sky covered by clouds”) with the caveat that “partly sunny” should only be used during daylight hours (!).
To my mind, “part” + “most” = whole. So “partly sunny” should be the same as “mostly cloudy” and “partly cloudy” should be the same as “mostly sunny.” Whichever one gets used tells me more about the temperament of the meteorologist than it does about the weather.
In response to your last question, I would ask, “Which is a more important weekend event, a significant one or a rather significant one?”
The big question is not what they do or should do, but why competitive forces have not resulted in meteorological images and phrases that more immediately convey what readers want to know.
Clearly, between TV, online sources, and the printed media, there are plenty of competitors for conveying weather forecasts. One possibility, then, is that licensing for becoming a meteorologist encourages one to be obscure (pun intended or unintended, depending on your inclinations). Another possibility is that media all use weather forecasts as a hook or advertising to tempt readers to access other material, and that no one has yet had any better ideas for accomplishing the middle ground of both conveying information and serving as a hook capable of the employer’s paying the meteorologist’s salary.
My main argument about the lack of clarity would actually be that weather forecasts depend on context and are not easy to convey in a still picture. The 4×4 chart you display does not explore whether either of the two news sources use the picture/phrase combinations to depict different daytime/nighttime conditions, or a change in weather over the course of a 24-hour day, or whether a series of preceding days that have been, say, 70% cloudy are now changing to a day that will be 70% sunny.
One news source could decide its readers prefer both the picture and the words always to match. Another could decide its readers might detect some useful secondary information from mismatching the words and pictures in a systematic way. At least one station I watch uses terms like cold or “rather cold” specifically to depend on the surrounding conditions–the latter tends to mean colder than the previous day or so, while the former tends to mean colder than the average temperature for the season. I’d prefer greater information about how my preferred news sources use these shorthand clues; but I notice that I prefer stations that use these subtleties to news sources that don’t, even if it takes me a while to figure them out. Most of all, I prefer news sources that show animated cloud-cover, precipitation, or temperature clips for a series of days or a period of hours within a day! No single image or short group of words alone can convey that.
In other words, the pictures and lack of clarity are simply an overview encouraging a reader whose situation depends on the details to read or listen in greater depth.
Most events–weather-related or human-related–are processes too complex to summarize in a single snapshot or pair of words. The complexity is inherent and understood. Does a book with a cloud in the form of a question mark on its cover and the title “the big questions” accurately convey its content? Does a wedding snapshot labeled “the happy couple” portend a happy marriage that will be half-empty, half-full, or what we all understand will be an evolution? We’d all love to know the answers in advance, but sometimes even the conveyers themselves want to hedge their bets.
It’s a simple identity: sunny minus partly sunny = mostly sunny. Same for cloudy, with cloudy equal to the opposite of sunny. You just have to assume that partly implies a small part (that’s how I read it anyway) and you can see that Weather Underground is right and Accuweather is crazy.
Of course, if you abandon my assumption about partly meaning less than half, then there is no distinction between partly sunny and partly cloudy. Doing this is inherently safer since you don’t rely on people’s interpretation of the word “partly.” Combining this with the empirical finding that absolutes in sunniness or cloudiness are much less probable than the spectrum in between, it looks like the weather channel is the smart one here. You would be almost as accurate (at least on sun levels) keeping a fixed forecast of “partly cloudy” every day. Precipitation is another story…
Discuss it biweekly and check the evidence semi-monthly.
My intuitive reaction to “Partly Sunny” is to prepare for sun.
My intuitive reaction to “Partly Cloudy” is to prepare for clouds.
Of course when I think about them I come to the opposite conclusions.
And then I don’t know which I should prepare for.
The most surprising part of this post is this: “for the first time in my life”. Every single time I get a “partly” forecast, I have to confront it. How is it possible that this is the first time in your life? Do you spend almost no time outside?
This is beyond me. I’m still trying to figure out what semi-boneless means at my local supermarket. :-)
When you say partly cloudy, there is no mention of what the other part is. While I would like to think if the other part were rain that that would be given the highest priority. Half cloud and Half rain then becomes “partly raining” because we give priority to the gloomier condition. With partly sunny, apparently the clouds aren’t even worth mentioning. I therefore agree with the standard that partly sunny is warmer than partly cloudy. If you were to abbreviate either of those to a one word answer they would just become sunny and cloudy.
For me, the general scale from highest to lowest would be:
Completely
Mostly
Equally (or Mixed)
Partly
Not-at-all
If I were running a weather site, I’d probably settle on something like:
Sunny
Mostly Sunny
Mixed Clouds and Sun
Mostly Cloudy
Cloudy
Just to be mostly clear. :)
““Partly cloudy” obviously (sic) means that the day will be generally sunny, but there will be times when there is cloud about. “Partly sunny”, on the other hand, means that although the day will generally be cloudy, there will be times when the clouds clear and the sun shines through.”
This is the definition given to me by two different TV weathermen I have spoken to in the past. Both were also degreed meteorologists.
Another tidbit – when they tell you there’s a 50% chance of rain, they are telling you that it is going to rain that day and 50% of their reporting or coverage area will get it.
Matt F wishes to talk about “partly xxxx” days. I think those are found in the San Fernando Valley of Los Angeles.
Isn’t this one of those “is the glass half empty or half full” things? I choose the one that makes me feel better. And on that, the Accuweather pictures make me feel better than the Weather Underground pictures, whether it be partly cloudy or partly sunny.
Which is wetter — rain or showers?
Roger,
What about “rain showers”?
It seems to me that the issue gets confused when we use two terms (sunny and cloudy) two measure one thing (how sunny it is). Because, let’s be honest, most of us care how sunny it is going to be, and sunny and cloudy are just opposites. If we are proposing the best way to talk about the weather, I say we scrap the whole two adjective system and just go by percent sunny. Thus we go from partly cloudy or mostly sunny to the unambiguous 60% sunny. And everyone will be sad on 0% sunny days. I still need to figure out how to do away with rain and showers but this should be a good start.
paying for weather infotainment and expecting anything less than a full blown circus just simply would not do.
this is a complexity problem?
Which is sunnier — “partly sunny” or “partly cloudy”?
Which is colder — “cold” or “rather cold”?
rather cold is cold modified, so it must be colder. it costs more.
by the same reasoning, partly sunny is sunnier than sunny. so sunny must be a median level of sunniness.
partly sunny must also be sunnier than partly cloudy.
Which is colder – ‘cold’ or ‘COLD’?
Which is colder – ‘COLD’ or ‘rather cold’?
Which is sunnier – ‘sunny’ or ‘cloudy’
I had a science class recently (within 4 or 5 years) and asked the same question. The Prof. told me that the two phrases SHOULD be used to depict the same degree of cloudiness, but that “partly-sunny” should be used during daylight hours and “partly cloudy” during evening hours.
How the terms are actually applied I’m not sure has any base in logic.