TAG: Weather And Meteorology
August 2, 2011– 10

It seems the sun won’t let up this summer, with many parts of the United States experiencing record-level temperatures. With the excessive heat comes the danger of overexposure to the sun, but it’s often hard to know you’re at risk until it’s too late. The newly released Wolfram Sun Exposure Reference App for iOS can aid in calculating just how much sun is too much and can offer recommendations on which SPF level to apply.

Wolfram Sun Exposure Reference App
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July 14, 2011– 5

On a moonlit stroll, a young man points to the cloudless sky and says, “Look—a full moon!”

His date is not impressed. “Technically,” she replies, “the Moon’s not full until 2pm, when its ecliptic longitude is opposite to that of the Sun.”

Hoping to save his pride, he replies, “But the Moon looks completely illuminated.”

“It’s never one hundred percent illuminated,” his date says, unfazed. She’s a tough cookie. “Oh, and on this side of the world it’ll be a corn moon.”

Pretending to check his watch, the young man gets confused. He remembers his science teacher explaining that the Moon reflects sunlight and that it is full when it is on the other side of the Earth from the sun, but the nighttime half of the Earth is on the opposite side of the Sun, so how could that be 2pm? Did the newspaper say it would be a full moon tonight, or did it say tomorrow night? And what’s a corn moon?

There’s only one thing he can do: look it up on Wolfram|Alpha!

One of the latest features added to Wolfram|Alpha is more coverage of full moons and other Moon phases. Back when people got their information from only a local newspaper, it was relatively simple to say that one night or another would be a full moon, because for a specific location, the time of a full moon would be closest to midnight on that day. But now it is easy to get your information from a newspaper that is far away, so its date can be off by a day. Of course, Wolfram|Alpha detects your location, so it is able to predict the date of the next full moon in your area, and the “Precise time” button reveals the exact time the full moon will take place.

corn moon 2012

Remember that because of time zone differences, there is always part of the world that is on a different day. And that affects labels like “corn moon”, which is the first full moon in September. The beginning and ending dates of September depend on the time zone, and sometimes the full moon is close to this boundary. The next ambiguous corn moon will be in 2012. More »

June 7, 2011– 3

Early on June 7, 2011, the Sun once again showed signs of waking up from the last solar minimum: it unleashed a powerful solar flare. The x-ray emission from this flare can be seen in Wolfram|Alpha:

Solar flares 3 am June 7, 2011 to 3 pm  June 7, 2011
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April 12, 2011– 3

Vacation planning season is upon us! Planning a vacation is no easy feat, but Wolfram|Alpha can help. With data on airlines, gas prices, weather, and currency, taking a trip has never been easier.

Let’s say you’re researching locations to take a family vacation and you want to know the average temperature of the locations at a specific time of year. Query something like “temperature May Hilton Head, Miami” to compare two locations’ average temperatures for that month.

Temperature May Hilton Head, Miami More »

March 29, 2011– 2

Spring has officially sprung, and here in the Midwest, we’re eagerly ice picking our way out of hibernation for some fun in the Sun! Some of us are enjoying the extended daylight hours, and others are jetting off to tropical spring break destinations.

While we were nestled by our office heaters, drinking Swiss Miss, and dreaming of the bright sunshine, we developed a few new tools in Wolfram|Alpha that give you facts on how to keep your skin healthy while enjoying the Sun. To get started, simply query “time to sunburn”. This query allows you to calculate how long your skin can be exposed to the Sun without burning based on your skin type, location, time, the level of Sun protection factor (SPF) you might be using, and how long you stay in the Sun. You can also select “UV index” for results based on the UV index, your skin type, SPF, and time in the Sun.

Time to sunburn

The personalized results show how long you can stay in the Sun before you’re likely to burn based on the factors you reported, a Sun protection advisory recommending an SPF level, and a UV forecast for your location. More »

December 22, 2010– 4

Oh, the weather outside has been mighty frightful in many parts of the U.S. and Europe these past few weeks! Your mother has told you, and we will remind you, that it is never a good idea to forgo your mittens during cold weather.

How many times have you dashed outside to find that the advertised temperature does not feel the same as you had expected? The wind plays a big role in how the air temperature feels on your skin. For example, today in Champaign, Illinois, the temperature is 21 degrees Fahrenheit, but factor in the wind, and it feels like 9 degrees Fahrenheit outside. Enter your current city in this handy widget and it will provide a wind chill temperature. (The widget is live, so go ahead and try it!)


Icy temperatures can cause frostbite, a condition where tissue such as skin is damaged, and in some cases destroyed, due to exposure to extreme cold. As we encourage our users to create their own widgets, one of our users arwheelock did so by creating a popular related Wolfram|Alpha Widget. This widget allows you to quickly compute how long your skin can be exposed to such weather conditions before becoming susceptible to frostbite. By simply entering the temperature and wind speed for your location, Wolfram|Alpha will tell you approximately how long your skin can be exposed to the conditions before developing frostbite.

So whether you’re off for an evening of caroling or an afternoon on the slopes, be mindful of the risks associated with leaving your mittens (or other cold weather gear) behind.

October 22, 2010– 3

Wolfram|Alpha has many trillions of pieces of data, many of which are facts about people, places, and things. All of this knowledge is built upon a computational engine that allows us to mash up topic areas and do impressive, if not outrageous, computations. In honor of it being Friday, we’ll share a few fun facts to get your mind curious about what else is waiting to be discovered within Wolfram|Alpha.

Fact: Your Halloween Jack-o’-lantern has 40 chromosomes.

Fact: There are 4.3 x 10^6 calories in one short ton of Snickers.

Fact: Lassoing the Moon from Earth will require about 239,200 miles of rope on average!

Fact: 36 degrees was the high temperature in New York City on the day Justin Bieber was born.

Fact: On April 1, 1976, just 47 years after Louis Marx popularized the yo-yo, Apple Computer was created—no joke!

These are just few of the fun facts highlighting data areas such as nutrition, species, science, weather, history, and events. What fun facts have you discovered in Wolfram|Alpha?

September 22, 2010– 4

Every day the Sun crosses the sky, rising in the east and setting in the west, but in detail its path is different every time. If it is winter, or if you live in the north, the Sun is lower and stays closer to the southern horizon. While the time of year and the location have similar effects, they act independently on the overall path. The Sun’s path is unique for your place and time.

You can see the sunpath today at your location; the default is the perspective of looking toward the southern horizon.

The path of the Sun for Champaign, Illinois on September 22, 2010

The autumnal equinox is tonight (in North America), but in Pyramid Point (a place close to the equator in the Pacific), the equinox will occur Thursday, close to noon, when the Sun will be almost overhead. More »

July 23, 2010– 6

Runners and cyclists can now get personalized physical activity and fitness results from Wolfram|Alpha. Our team has added enhanced activity formulas to provide specific results that account for the individual differences among all types of runners and cyclists. Whether preparing for a race or monitoring regular routines, athletes and enthusiasts alike can now calculate actual performance results and compute performance predictions and the impact of exercise on personal physical fitness.

You can calculate your own results in Wolfram|Alpha by using a natural language input such as “cycling 72.13 miles for 240 minutes” or you can type in “cycling” to explore all of the formula’s options. For example, a cyclist who is preparing for, or who has just completed, a race can calculate a variety of user-specific metabolic properties, like the amount of fat and the number of calories burned, by taking into account factors such as age, gender, height, weight, incline, resting heart rate, and wind speed and direction. Below are sample results from Wolfram|Alpha when calculating the speed a 25-year-old male cyclist needs to maintain to complete a race in 240 minutes:

Calculating the speed a 25-year-old male cyclist needs to maintain to complete a race in 240 minutes

To complement the results of Wolfram|Alpha’s calculations, cyclists can compare their speed or pace with world record times by clicking the “Show comparisons” link.

Runners can input similar information and calculate calories and fat burned; oxygen consumed; heart rate; equivalent activities; conversions for speed, pace, distance, and time; and performance predictions. For this example, we convinced a member of our team to share his post-race results from the 2009 Chicago Marathon: More »

July 2, 2010– 7

Sunday is the United States’ Independence Day, and one of the hottest days of the year in this part of the country. Many Americans will celebrate the day with outdoor activities such as barbecues, parades, and fireworks. Chances are that after all the corn on the cob and fun in the sun, they’ll be looking to celebrate with some air conditioning, too! All that cooling will require a few degree days!

What’s a degree day? A degree day quantifies the amount of heating or cooling required to heat or cool an inside space.

Suppose you want to maintain an inside temperature of 65°F. This 65°F is called the base temperature. (65°F might sound cool, but this artificially low number is used because the actual temperature in the building will be raised by bodies and other inside sources of heat.) If the weather forecast for Champaign is as hot as expected for U.S. Independence Day—definitely above 65°F—then you’ll need to cool the building. The amount of cooling required is the difference between the base temperature and the outdoor temperature, multiplied by the time over which the temperature is different. If it is cooler outside than 65°F then you’ll need to heat the building, again by an amount equal to the product of the temperature difference and the time.

To make sense out of that, just type “degree days” into Wolfram|Alpha.

Degree days formula in Wolfram|Alpha

The temperature history pod contains a plot of the temperature over the time period of the calculation—one month back by default. If you are used to using Wolfram|Alpha to check the weather this plot should look familiar, but with some differences. The horizontal red line across the plot is the base temperature. The part of the plot that is above the red line is shaded in blue. That’s because when the temperature is above the base temperature, you have to cool the building. The number of cooling degree days is the area of the blue region. Similarly, the number of heating degree days is the area of the red region, which extends from the red baseline down to temperatures below the base temperature. More »

June 3, 2010– 2

Since Wolfram|Alpha launched in 2009, we’ve had numerous requests to add data on climate. As part of our one-year anniversary release, we recently added a vast set of historical climate data, drawing on studies from across the globe, which can be easily analyzed and correlated in Wolfram|Alpha.

You can now query for and compare the raw data from different climate model reconstructions and studies, as reported in peer-reviewed journals and by government agencies, many of them covering more than a thousand years of history. The full set of reconstructions was chosen from as broad a collection of sources as possible, from well-known records such as ice cores and tree rings, to corals, speleothems, and glacier lengths—and even some truly unusual ones, like grape harvest dates.

Or are you more interested in global greenhouse gas concentrations?

If you’re interested in exploring this vast area of climatology yourself, you can start by looking at a detailed summary of the most prominent models in literature: simply ask Wolfram|Alpha about “global climate”, which will bring up a selection of data sets that have figured prominently in the news over the past few years.

Global climate studies in Wolfram|Alpha

Wolfram|Alpha can also compute a more local analysis of recorded temperature variations. For example, you can compare the temperature variations recorded in specific parts of the globe, like the Northern Hemisphere. Or you can ask about studies conducted in specific countries, like the United Kingdom or Japan. More »

March 17, 2010– 6

Today when you hear about global warming, the first thing that comes to mind is probably carbon dioxide; however, there are many greenhouse gases that may contribute to this phenomenon. Wolfram|Alpha now provides information on the relative global warming effects of about 30 common pollutants in the atmosphere using the global warming potential (GWP) index.

The GWP index estimates how much a certain chemical will add to global warming compared to the same mass of carbon dioxide over a certain time span. The data Wolfram|Alpha uses is from the 2007 report of the Intergovernmental Panel on Climate Change (IPCC).

Let’s take a look at some of this data by asking Wolfram|Alpha about the “gwp of methane”. Here you are able to see three different time horizons for methane: 20 years, 100 years, and 500 years. These different time horizons allow you to see the short-term and long-term contributions that methane will make to global warming in the atmosphere. You may also notice that as the time horizon gets larger, the GWP actually decreases—which seems counterintuitive, but makes sense as soon as you see that methane has an atmospheric lifetime of about 12 years. This is a fairly short lifetime, so methane’s effect on global warming declines as the time horizon increases. A simple click on the “Show comparisons” button pulls up a comparison of methane’s GWP to those of other greenhouse gases. You can also adjust the time horizons to see how methane compares to other greenhouse gases in the short and long term.

Wolfram|Alpha's results for the global warming potientals of methane

GWP values can also be compared for multiple greenhouse gases. For example, an input of “gwp of methane and carbon tetrachloride” provides a comparison of the two gases. The first pod displays the time horizons of both chemicals so you are able to see that carbon tetrachloride contributes much more to global warming than does methane. Moving down to the next pod, it may become more obvious why carbon tetrachloride contributes more: it has an atmospheric lifetime of 26 years, more than twice as long as methane’s.

Wolfram|Alpha compares the global warming potientals of methane and carbon tetrachloride

We are currently working to add a greater variety of climate change and global warming data to Wolfram|Alpha. We encourage you to submit feedback on this feature, as well as any suggestions or ideas you may have.

February 2, 2010– 3

If all you know about Groundhog Day is what you learned from watching the Bill Murray movie, well… you’re actually quite well informed. The good people of Punxsutawney, Pennsylvania really do gather at Gobbler’s Knob each February 2 to find out whether a 20-pound groundhog named Punxsutawney Phil will see his shadow, thus foretelling six more weeks of winter—or not, foretelling an early spring.

In more than 120 years of predictions, there have only been 15 occasions on which Phil hasn’t seen his shadow. The National Climatic Data Center has estimated Phil’s accuracy rate at around 39%, but true Phil fans (or skeptics) can do their own analysis of Phil’s track record with Wolfram|Alpha.

Let’s take 1950, for example: according to Punxsutawney’s “Inner Circle,” Phil did not see his shadow that year. Ask about “punxsutawney, pennsylvannia weather feb. 2 1950,” and you discover that practically the entire day was overcast and foggy: not good conditions for a giant rodent to see his shadow. But an early spring? Check the results for “punxsutawney, pennsylvannia weather february 1950” and it’s hard to overlook the plunging temperatures and snowfall in the latter part of the month. Sorry, Phil. More »

January 20, 2010– 2

Here in the Northern Hemisphere we’re well into the doldrums of winter. The cold, wind, rain, sleet, and snow keep many of us cooped up during the winter months. It’s about this time that cabin fever sets in and that big pile of fresh powder on the ground starts looking more and more like a winter playground. But before you head outside for a little bit of outdoor fun or a quick trip across town during these blustery winter months, it’s important to prepare for outdoor temperatures to avoid potentially serious physical effects from cold, such as frostbite.

Frostbite is a condition where tissue such as skin is damaged, and in some cases destroyed, due to exposure to extreme cold. Wolfram|Alpha has a tool that allows you to quickly compute how long your skin can be exposed to such weather conditions before becoming susceptible to frostbite.

A simply query of the term “frostbite” in Wolfram|Alpha will bring up the calculator featured below. You can update the default values for temperature and wind speed with the ones for your area. (Did you know you can simply enter “weather” into Wolfram|Alpha to get your local weather information?)

In this example, Wolfram|Alpha calculates that at a temperature of 7 °F coupled with a wind speed of 40 mph, frostbite can occur within 24 minutes.

Wolfram|Alpha calculates the risk of frostbite

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December 3, 2009– 3

Psychrometry deals with the thermodynamic properties of gas-vapor mixtures. Air-water vapor mixtures are the most common systems studied because of their importance in heating, ventilating, air conditioning, and weather reporting.

Students of engineering are introduced to the subtleties of psychrometry in their thermodynamics courses. But we are all exposed to psychrometry any time we watch weather reports on television. Your favorite meteorologist probably speaks about the relative humidity, dry bulb temperature, and dew point temperature.

Let’s start our exploration of psychrometry by querying “psychrometric properties“. Wolfram|Alpha returns a presentation of data for moist air, including a graph known as a psychrometric chart.

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August 14, 2009– 7

Does this summer seem hotter than last year’s? Are you debating between a trip to Miami or Florence in the springtime? Or perhaps heading to Tokyo in November, and wondering how to pack? Wolfram|Alpha has a number of helpful tools to answer your weather questions, by retrieving current conditions, forecasts, and historical data from weather stations located all over the world.

For example, simply enter “weather” into the computation bar, and Wolfram|Alpha’s geoIP capabilities identify your approximate location and produce the latest records from your nearest weather station. The “Latest recorded weather” pod may feature information like the current temperature, relative humidity, wind speed, and conditions, such as clear, thunderstorms, or fog. Go ahead and click here to give it a try for your area.

weather_1

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June 19, 2009– 17

We have been highlighting ways Wolfram|Alpha can be a part of your daily life, and we think you will find it a great addition to your other travel resources. Whether you are traveling for business or pleasure, Wolfram|Alpha can become a part of your planning by providing essential data.

Let’s say you live in San Francisco, California and want to fly to Miami, Florida. Type “San Francisco airports” into Wolfram|Alpha, and your results conveniently include the airport code “SFO” for the San Francisco International Airport. You can use Wolfram|Alpha to instantly access all codes for all U.S. airports, even those as obscure as 11II. Results also list elevation of the airport, number of runways, local time, and other nearby airports in case you want to search for better alternatives for your departure and arrival cities.

San Francisco airports

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