Fair Skies: What This Weather Term Really Means
Believe it or not, this weather term actually has an official definition. Read more!
Quick Reference: What “Fair Skies” Means
- Official definition: less than 40 percent cloud cover, no precipitation, and no extreme weather.
- What it describes: the sky condition only, meaning how much cloud is overhead. It is one of the 5 elements in a basic forecast.
- What it does not tell you: the temperature. You can have fair skies at 24 degrees F or 84 degrees F.
- Who sets the rule: the National Weather Service, which measures sky cover on a scale from clear to cloudy.
- Should you pack extra? Fair skies means little cloud and no rain, so check the temperature and wind lines separately before you decide.
You are about to hop on a plane for a distant land, and like many people, you might head to your computer to check the weather to see what is forecasted for your trip: 50 degree temperatures under fair skies. You “get” the temperature part, but what exactly does it mean by fair skies? Sounds innocuous enough, but should you pack anything extra?
We hear many descriptive terms used for a weather forecast. Some are terms we know (wind, chance of rain, snow), but others can be shrouded in a bit of mystery. We sort of know what they mean. Blizzard is a great example. We know it involves snow and wind, but not necessarily the specifics. Here is the official definition: large amounts of snow or blowing snow, 35 mph winds, with a visibility of 1/4 mile or less, for a duration of 3 hours or more.
Fair skies is another example. Believe it or not, this term is more than just a descriptive one. It too has an official definition. (Check out more weather terms here.)
The 5 Elements of a Basic Forecast
First, understand that your basic weather forecast includes the following 5 weather elements: precipitation, probability of precipitation, temperature, wind, and sky condition. Read together, those five lines give you and your family the full local picture so you can plan the day accordingly.
The trouble is that people often read one line and skip the rest. “Fair skies” gets treated like a summary of the whole day when it only speaks to one of the five. Keep the elements separate in your head and the forecast stops feeling like a riddle.
What “Sky Condition” Actually Measures
Sky condition refers to the amount of cloud cover overhead. Nothing more. Sky conditions are an important part of the weather equation, and along with the other 4 weather elements, they provide the full local forecast picture so you and your family can plan accordingly.
Forecasters do not eyeball this by feel. Sky cover is reported as a percentage of the dome of the sky that clouds fill, from a spotless zero to a solid overcast. That single percentage is what turns into the plain-English word you read, whether that word is “cloudy,” “mostly sunny,” or “fair.”
How the National Weather Service Defines Each Sky Term
Here is how the National Weather Service defines each of the sky condition terms you often hear. The percentages describe the average sky cover, meaning the share of the sky the clouds take up.
| Term | METAR code | Cloud cover (oktas) | Coverage percentage | When NWS uses it |
|---|---|---|---|---|
| Clear | SKC (human observer, all altitudes) or CLR (automated ASOS/AWOS, capped at 12,000 ft AGL) | 0 oktas | 0% | No clouds detected. SKC is used by certified observers who can confirm the sky is clear at all levels. CLR is used when the automated station detects nothing below 12,000 ft but cannot rule out higher clouds. (NWS METAR standards / WMO Code Table 2700; FAA Aeronautical Information Manual) |
| Few | FEW | 1-2 oktas | 1/8 to 2/8 (roughly 12-25%) | Sky is mostly clear; isolated clouds are present. Conditions are generally considered fair weather. Not a ceiling layer for aviation purposes. |
| Scattered | SCT | 3-4 oktas | 3/8 to 4/8 (roughly 37-50%) | Clouds cover between a third and half the sky. Partly cloudy in plain language. Not an official ceiling for aviation unless cloud base is below minimums. |
| Broken | BKN | 5-7 oktas | 5/8 to 7/8 (roughly 62-87%) | More sky covered than open. Constitutes an official ceiling layer in aviation reporting. Described as mostly cloudy in general weather language. |
| Overcast | OVC | 8 oktas | 8/8 (100%) | Complete cloud cover. Constitutes a ceiling. Reported when the entire sky is covered regardless of cloud type or altitude. |
| Obscured | OVX / VV (vertical visibility) | N/A | Sky not determinable | Sky is hidden by a surface-based phenomenon such as fog, smoke, blowing snow, or heavy precipitation. Vertical visibility is reported in place of a cloud ceiling height. Not a cloud-cover category; it means the observer cannot see sky at all. |
Notice that “fair” is the odd one out. Every other row is a straight cloud-cover range, but fair carries two extra conditions: no precipitation and no extreme weather. The full list of these definitions comes straight from the National Weather Service forecast terms guide, which spells out the sky cover ranges forecasters use across the country.
So What Do “Fair Skies” Really Mean?
So, hearing “fair skies” lets you know how much blue sky you are likely to see. It has no bearing on what the temperature is outside. That is a separate weather element. In fact, you can have “fair skies” whether the temperature is 24 degrees F or 84 degrees F.
That is the catch that trips up most travelers. Fair skies on the forecast is a promise about clouds and rain, not about warmth. A crisp fall morning and a mild spring afternoon can both wear the same fair label. Read the temperature and wind lines before you pack, and let the sky condition tell you only what it is meant to: whether you will see sun.
Fair Skies vs. Clear Skies
People use “fair” and “clear” as if they were the same word. They are not. Clear means almost no cloud at all, 0 to 10 percent sky cover, a wide-open blue dome. Fair allows for a good deal more, up to just under 40 percent cloud cover, plus the two promises of no precipitation and no extreme weather.
Put simply, every clear day is fair, but not every fair day is clear. Fair is the forecaster’s way of saying pleasant and settled without claiming a cloudless sky. If you see scattered clouds drifting past on a fair-skies day, the forecast is doing exactly what it promised.
Reading Sky Cover Like a Forecaster
Forecasters have measured cloud cover for generations by dividing the sky into eighths, a unit called an okta. A clear sky is zero oktas, an overcast sky is eight. The percentage ranges in the table above are the plain-English translation of that older eighths system, which is why “partly cloudy” and “partly sunny” land on the same middle band: they are two names for a sky that is somewhere between a third and two-thirds full of cloud.
You can practice this yourself. Step outside, picture the whole sky split into eight equal slices, and count how many hold cloud. Three or four slices puts you in partly cloudy country. One slice or none is clear. Under about half, with no rain in sight and nothing stormy brewing, and you are standing under fair skies.
Fair Skies Across the US and Canada
The sky-cover math is the same wherever you travel, but the wording on your forecast can shift once you cross a border. In the United States, the National Weather Service uses the terms in the table above, with “fair” reserved for that under-40-percent, no-rain, no-extremes sky.
| Region | Representative city | Average annual clear days | Peak clear-sky months | Notes |
|---|---|---|---|---|
| Desert Southwest | Yuma, AZ | Approximately 300 | April-June, September-November | Consistently the sunniest city in the US by NOAA NCEI data (1991-2020 normals). Phoenix records roughly 299 clear days per year by the same measure. Summer monsoon (July-August) briefly reduces the clear-day count. |
| Southern California coast | San Diego, CA / Los Angeles, CA | San Diego approximately 266; Los Angeles approximately 284 | September-November | June Gloom (marine layer May-July) reduces clear days despite abundant annual sunshine. The coastal cloud layer is shallow and often burns off by midday, leaving high sunshine-hours totals even in low clear-day months. (NOAA NCEI via Current Results) |
| Great Basin | Las Vegas, NV | Approximately 294 | April-June, September-October | Low humidity and desert terrain produce extremely low annual cloud cover. Summer convective storms are brief and localized. Among the sunniest non-desert cities in the western US. |
| Pacific Northwest | Seattle, WA | Approximately 71 | July-September | Among the fewest clear days of any major US city. Persistent low clouds October through May. The summer dry season is notably sunny, which can mislead visitors about annual patterns. (NOAA NCEI) |
| Great Plains | Denver, CO | Approximately 115 clear; 300+ sunny (clear plus partly cloudy) | September-October, March-April | High altitude and low humidity produce intense solar radiation. The sunny count (clear plus partly cloudy) exceeds Miami and Los Angeles. Winter chinook winds frequently clear skies rapidly after storm systems. |
| Southeast | Tampa, FL | Approximately 101 clear; 239 sunny | October-May | Summer afternoon thunderstorms (June-September) are frequent but brief, reducing the strict clear-day count while leaving substantial daily sunshine. Florida ranks second nationally for annual sunshine hours. (NOAA NCEI) |
| Northeast | Buffalo, NY / Boston, MA | Buffalo approximately 52; Boston approximately 98 | July-August | Great Lakes lake-effect cloud and snow suppresses Buffalo’s clear-day count to among the lowest in the continental US. Boston benefits from cold-season high-pressure systems for occasional crisp clear days but averages fewer than 100 per year. |
| Canadian Prairie provinces | Saskatoon, SK | Approximately 260 sunny days (southern Saskatchewan: 2,400+ sunshine hours per year) | June-August | Southern Saskatchewan and Alberta rank among the sunniest regions in Canada, often exceeding many US Southeast cities in annual sunshine hours. Winter cold is severe but skies are frequently clear under Arctic high-pressure systems. (Environment and Climate Change Canada) |
So if a Canadian forecast promises “a mix of sun and cloud” while a US forecast for the same front reads “fair,” the two are describing much the same sky. When in doubt, look at the cloud-cover percentage or the precipitation line rather than the label alone.
So, Now You Are in the Know
So, now you are in the know. Fair skies is a real, defined term, not a vague guess, and it speaks to one line of the forecast only. Check the temperature and wind before you pack, glance at the sky-cover word to picture the day, and you will read a forecast the way a forecaster writes it. Is there another weather term you are not sure about, like humidity? Browse more plain-English explainers in our weather section, or ask us in the comments.
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Fair Skies: Frequently Asked Questions
What does “fair skies” mean in a weather forecast?
Fair skies is an official National Weather Service term for a sky with less than 40 percent cloud cover, no precipitation, and no extreme weather. It describes the sky condition only, meaning how much cloud is overhead, and says nothing about the temperature.
Is “fair” the same as “clear” or “sunny”?
Not quite. Clear or sunny means 0 to 10 percent cloud cover, an almost cloudless sky. Fair allows up to just under 40 percent cloud cover, along with no rain and no extreme weather. Every clear day is fair, but a fair day can still carry a few scattered clouds.
Does “fair skies” tell me how warm it will be?
No. Sky condition and temperature are two separate elements of the forecast. You can have fair skies at 24 degrees F or at 84 degrees F. Always read the temperature and wind lines before you decide what to pack.
What are the 5 elements of a basic weather forecast?
A basic forecast covers five elements: precipitation, probability of precipitation, temperature, wind, and sky condition. Fair skies speaks only to the sky condition line, so read all five together for the full picture of your day.
How do forecasters measure cloud cover?
Sky cover is reported as the percentage of the sky filled with cloud, traditionally counted in eighths called oktas. A clear sky is zero eighths, an overcast sky is eight. The percentage ranges you see in a forecast, from “clear” at 0 to 10 percent up to “cloudy” at 90 to 100 percent, are the plain-English version of that system.
Why does a Canadian forecast say “a mix of sun and cloud” instead of “fair”?
The cloud-cover math is the same, but the wording differs by country. Environment Canada often uses “a mix of sun and cloud” for the same middle-of-the-road sky that a US National Weather Service forecast might call “fair” or “partly sunny.” When in doubt, check the cloud-cover percentage or the precipitation line rather than the label.
Should I pack rain gear if the forecast says fair skies?
Fair skies means no precipitation is expected and no extreme weather, so rain gear is usually not the priority for that day. Conditions can still shift in coastal and mountain areas, so glance at the probability of precipitation and the long-range outlook before a long trip.
This article was published by the Staff at FarmersAlmanac.com. Any questions? Contact us at questions@farmersalmananac.com.
- Farmers' Almanac Staff
- Farmers' Almanac Staff
- Farmers' Almanac Staff
- Farmers' Almanac Staff
I’ve heard the blessing fair skies and following seas.. What does the following seas part mean?
WIERD but COOL
WIERD.
weird
Fair to middling is an expression I have heard my parents and others say a few years ago when I was young. It means from being not bad weather out to getting better [nicer] for however long.] It works for me God bless you all.
What does dew point mean? How is it calculated and what effect does it have on weather?
A term I have often hear is “fair to middling”. Since fair skies has an actual definition, I presume “fair to middling” also has one. What does that mean in actual weather?