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Highest/Lowest Real-time
Lowest Temperatures:
()=-273.15 °C
Srednekolymsk (RU)=-44.19 °C
Ust-Nera (RU)=-42.71 °C

Highest Temperatures:
Bamako (ML)=35 °C
Abuja (NG)=35 °C
Asuncion (PY)=34 °C

Highest Pressure:
Nizhniy Novgorod (RU)=1038 hpa
Samara (RU)=1037 hpa
Moscow (RU)=1036 hpa

Lowest Pressure:
()=0 hpa
Leh (IN)=610.65 hpa
Thimphu (BD)=643.31 hpa

Strongest Winds:
Magadan (RU)=18.51 m/s
Dikson (RU)=14.56 m/s
Aberdeen (GB)=14.4 m/s

Most Rain:
Albany (US)=17.57 mm
Lusaka (ZM)=11.34 mm
Nauru (NR)=7.59 mm

Most Snow:
Khorugh (TJ)=2.43 mm
Akureyri (IS)=2.05 mm
Yelizovo (RU)=2.04 mm

Minimum Temp. Yesterday:
()=-273.15 °C
Ust-Nera (RU)=-46.97 °C
Susuman (RU)=-46.4 °C

Maximum Temp. Yesterday:
Laverton (AU)=42.58 °C
Mount Isa (AU)=39 °C
Wiluna (AU)=38.68 °C

Biggest difference yesterday:
Carnarvon (ZA)=26.96 °C
De Aar (ZA)=26.81 °C
Addis Ababa (ET)=24.77 °C

Smallest difference yesterday:
()=0 °C
Olonkinbyen (SJ)=0.48 °C
Grytviken (GS)=0.66 °C

Highest temp last 31 days:
Nukualofa (TO)=55 °C

Lowest temp last 31 days:
Antarctica ()=-64.59 °C

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FAQ: Weather
FAQ (Frequently Asked Questions) >Weather
Can it hail in the winter - is hail the same as sleet?Can it thunderstorm in winter?I've heard that "fog eats snow." Is there an explanation for this?What are Heating Degree Days?
What are jetstreams?What is a Nor'easter? Why is it called that?What is an Alberta Clipper?What is dew point?
What is the difference between partly cloudy, partly sunny?What is the difference between sleet and freezing rain?What is the difference between snow flurries and snow showers?When do maximum and minimum temperatures occur?
Why are some thunderstorms tinted green? Does it indicate severe weather?Why do leaves turn in the fall?Why does it snow more in the mountains?
Can it hail in the winter - is hail the same as sleet?
Hail usually falls during severe thunderstorms in the summer. Rain drops are pulled back up high into the atmosphere because of powerful thunderstorm updrafts. The upper atmosphere is always very cold, even in the summer. So, when the rain drop gets high enough in the thunderstorm cloud, it freezes into a ball of ice. Then it falls again, with part of the ice ball melting. It can then be pulled back up high into the cloud, freezing again, and becoming slightly larger. The hailstone can go through this cycle several times before it gets heavy enough to finally fall to the ground as a hail stone.

Thunderstorms are rare in the winter, but they CAN happen. But usually, the thunderstorm clouds are not as tall as they are in the summer, so it is less likely that the hail process can form. But it IS possible to hail in the winter - just not very likely. But balls of ice often fall in the winter. These are actually ice pellets, or sleet. It is different than hail because it does not go through the hail forming process. Sleet happens when snow from a cloud falls through a warmer layer in the atmosphere, then melts into a raindrop, but then falls through a colder layer again, freezing it into an ice pellet.
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Can it thunderstorm in winter?
Yes, thunderstorms can occur any month of the year anywhere in the United States. However, they are most frequent during the summer months.
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I've heard that "fog eats snow." Is there an explanation for this?
While fog doesn't literally eat snow or make it vanish before your eyes, it is true that the presence of fog will make the snow melt faster. Of course, the above-freezing air temperature will contribute to snowmelt. But when fog forms, condensation is taking place. The process of condensation releases energy in the form of heat, which gets released into the air. This added heat will increase the rate that the snow melts. Also, the water droplets from the fog itself will melt the snow to a certain extent.
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What are Heating Degree Days?
Heating Degree Day (or HDD) is a unit that helps us understand how much energy must be used to heat (or cool) our homes to a comfortable level. It is assumed that 65° Fahrenheit is a comfortable indoor temperature. So, if the outdoor temperature is colder than 65°, then you will need to use some energy to heat your house up to that 65° level. The number of HDD will indicate how much energy you will need to use.

The formula for determining HDD is simply subtracting the average outdoor temperature for the day from 65. It looks like this: HDD=65-T, where T indicates the average outdoor temperature. T is determined by simply taking the high temperature for the day, adding it on to the low temperature for the day, and dividing by 2. It looks like this: T=(high temperature + low temperature)/2.

The higher the HDD, the more heat it took to heat your home to a comfortable level. The lower the number, the less heat.

You can tell if you are using more or less energy during the winter by checking the number of HDD used, and comparing it with average HDD levels from years past.

HDD is very important to fuel companies, who must provide heating fuel, and be prepared by ordering more, or less, fuel depending on how much energy is being expended based on the HDD numbers.

The summertime equivalent of HDD is CDD - Cooling Degree Days! It follows the same idea as HDD, except you subtract 65 from the outdoor temperature, instead of the other way around.
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What are jetstreams?
At high altitudes, very strong winds are found, conventionally (for aviation forecasts) with speeds of 80 knots (40 m/s) or more, but most often with speeds in the range 120 to 160 knots (60-80 m/s), and in extreme cases, over 200 knots (100 m/s). These very strong winds are found in relatively narrow horizontal, and even narrower vertical space, and are known to meteorologists as jetstreams: named by Carl-Gustav Rossby in 1947, following research in the USA. However, the existence of jetstreams had been suspected theoretically for many years before, and, though not recognised as such, had been picked up by Zeppelin flights in the Great War (1914-1918) flying at 20000 ft/6 km on return to Germany.
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What is a Nor'easter? Why is it called that?
A Nor' Easter is an area of low pressure that forms in the southeastern United States, or along the East Coast. These storms move north along the coast where they will usually interact with colder air moving south and east out of Canada. The two ingredients combine to create a winter storm that can drop several inches of snow in the northeast and New England states. The track of the low pressure is what usually determines how much snow we get in northern New England. If the storm is too far inland, the snow may mix with rain or sleet, and if the storm is too far off the coast, it could miss us completely. When the storm track is just right, we could see some of the heaviest snowfall totals the winter season can bring.
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What is an Alberta Clipper?
An Alberta Clipper is an area of low pressure that usually forms over the Canadian province of Alberta. During the winter, these weather systems will pass through the Great Lakes and New England regions. These storms are usually quick moving, and can drop some generally light snow. Cold air can follow the passage of an Alberta Clipper, but temperatures will usually moderate in a day or two. An Alberta Clipper may sometimes dip south across the Mid Atlantic region, and develop off the eastern coast of the United States. This could turn the storm into a Nor' Easter.
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What is dew point?
The technical definition of the dew point (or dew point temperature) - is that it is temperature at which water vapor in the air will condense into liquid form if the air temperature lowers to match that dew point temperature. The dew point can tell us many useful things about the weather.

Water vapor is a gas, and is one of several gases that make up the atmosphere, with nitrogen and oxygen making up the bulk of it. The water vapor content in the air can vary, depending on the weather conditions. The dew point is an indication of just how much moisture is in the air. If the dew point is high (like in the 60s or 70s), then that indicates a lot of water vapor in the air. If the dew point is low (like in the 40s or lower), then that indicates less water vapor, hence the air is drier.

The dew point is either lower or the same as the air temperature. It is never higher. When the air temperature comes down to the dew point, the water vapor will condense into tiny water droplets. That is how clouds form!

With weather balloons, we can measure the air temperature and the dew point at any level in the atmosphere. Where the air temperature is the same as the dew point, that will tell us at what level the clouds are. If that happens right near the ground, then a cloud will form right on the ground - and that's called fog! So, knowing the air temperature and the dew point can tell us if fog will form.

Since the air temperature cannot go lower than the dew point, then the dew point is often a good indicator of what the low temperature will be. If the dew point is below the freezing mark (32°), that can indicate the possibility of frost, which is important to farmers and gardeners in the spring and fall.

The difference between the air temperature and the dew point can tell us what the relative humidity is. A complicated formula is used to figure it out exactly, but when the air temperature and the dew point are the same, then the relative humidity is 100%. And that means fog.

The lower the relative humidity is, the more drying power the air has. This can be a good indicator of brush fire danger, if the RH (relative humidity) is low for a long period of time.

The dew point can also be used to measure human comfort in the summer. When the dew point is in the 60s or higher, there is so much water vapor in the air that it is difficult for our bodies to stay dry. Our natural cooling process through perspiration does not work very well with high dew points. When the dew point is in the 50s or lower, the air is more comfortable. But if it gets too low, then that can indicate very dry air, which can lead to dry skin and scratchy throats.

And of course, the dew point indicates when dew will form on the grass (or frost, when it is cold enough).
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What is the difference between partly cloudy, partly sunny?
There is a reason everyone is confused about these terms, but it really doesn't have to be so complicated! For decades, they both meant a mix of sun and clouds, and "partly cloudy" indicated somewhat sunnier conditions and "partly sunny" indicated somewhat cloudier conditions. That was confusing for people to think "partly sunny" had less sun than "partly cloudy", and "partly cloudy" had fewer clouds than "partly sunny". Now the official National Weather Service definition tells us "partly cloudy" means between 3/8 and 5/8 of the sky is covered by clouds and "partly sunny" also means between 3/8 and 5/8 of the sky is covered by clouds, but the term "partly sunny" is used only during daylight hours. Apparently we've all been over thinking this whole "partly sunny" and "partly cloudy" thing!

When there are just a few clouds, it's Mostly Sunny (or Mostly Clear at night).

When there are more than just a few clouds, but still more in the way of clear skies, then it's Partly Cloudy.

When the clouds become more numerous than the sunny areas, then it Partly Sunny.

When there are clouds almost everywhere, but still a few, small sunny breaks, then it's Mostly Cloudy.

Notice that Partly Cloudy indicates sunnier conditions than Partly Sunny! So, even though the word, "cloudy" is in "Partly Cloudy" and the word, "sunny" is in "Partly Sunny," it does not mean that Partly Sunny is sunnier than Partly Cloudy. It's just the other way around.

Confused? It's just a matter of getting used to.
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What is the difference between sleet and freezing rain?
It helps to remember that the precipitation has a long ways to travel, from the cloud to the ground, and there can be layers of warmer and colder air between the ground and the cloud, which changes the form the precipitation will be in.

Even rain usually starts off as snow when it falls from the clouds, but it melts as it runs into warmer air, and falls as raindrops if it is warm all the way through to the ground.

Freezing rain occurs when the snow coming out of the cloud falls through a warm layer, melts into rain, but the ground itself is colder than 32 degrees. Then the rain freezes on contact and forms a layer of ice.

Sleet forms when the layer of colder air near the ground is a little thicker, ...The rain drops have a chance to freeze into ice pellets BEFORE they hit the ground, and they bounce around a bit, instead of forming a smooth layer of ice.

When it is snowing....the air is generally colder than 32 degrees from the cloud, all the way to the ground, so the snow never melts, and it never has to refreeze.

But it can be warmer than 32 degrees, and the snowflake can still survive.

This can happen if the air is dry enough. The snowflake falls into the warmer air, and they begin to melt. However, if the air is dry, the water quickly evaporates, cooling the surrounding air, and slowing the melting of the snowflake.

That is why on some occasions, it can be warmer than 32 degrees, and we will still find some big fat wet snowflakes that survive and build up on the ground.
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What is the difference between snow flurries and snow showers?
Snow Flurries: Light snow falling for short durations. No accumulation or light dusting is all that is expected.

Snow Showers: Snow falling at varying intensities for brief periods of time. Some accumulation is possible.

Snow Squalls: Brief, intense snow showers accompanied by strong, gusty winds. Accumulation may be significant.

Blowing Snow: Wind-driven snow that reduces visibility and causes significant drifting. Blowing snow may be snow that is falling and/or loose snow on the ground picked up by the wind.
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When do maximum and minimum temperatures occur?
A common misconception, is that it must be coldest in the middle of the night, and warmest around midday. On some occasions, mainly due to air mass changes, this may be correct, but not usually. The lowest (minimum) temperature usually occurs a little while after sunrise, and the highest (maximum) temperature usually occurs after midday --- sometimes as late as 3 or 4 hours after midday.

To understand why, it is necessary to consider that thermal energy during the 24 hours is radiating continually from the surface of the earth (at long wavelengths), and incoming solar (relatively short wave) radiation obviously only when the sun is above the horizon. With the sun below the horizon (night), outgoing radiation allows the surface to cool, and the temperature drops. After sunrise, incoming solar radiation counteracts this loss of heat, but only after a lag - which can be up to an hour or so in winter with a low solar elevation.

The minimum temperature occurs when there is a balance between outgoing and incoming radiation. As the sun rides higher in the sky, increasing amounts of short-wave radiation are available to heat the ground, and therefore available to heat the overlying air. Although outgoing land-based radiation is also increasing, solar heating is dominant. The temperature rises, until, past noon, incoming solar radiation starts to decline again.

The highest(maximum) temperature occurs when heat gain due to incoming solar radiation, and heat loss due to outgoing terrestrial radiation balance: this occurs some time after midday.
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Why are some thunderstorms tinted green? Does it indicate severe weather?
Green thunderstorms do exist, but there's no concrete evidence as to why they're associated with severe weather, hail or tornadoes, or why they have the green color in the first place. One theory is that more massive thunderstorm clouds (cumulonimbus) will scatter more sunlight, giving a darker bluish color. If this occurs late in the afternoon when the western sky reddens during the setting of the sun, then the light scatters such that it appears green to the viewer's eye. Another theory is that green thunderstorms contain large hailstones, and those stones refract light differently than raindrops. Though some green thunderstorms are indeed severe, there's no proof that all green thunderstorms are severe, or that all severe thunderstorms are green.
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Why do leaves turn in the fall?
The fall colors of yellow, orange, and red are actually always in the leaves, even during the spring and summer. But during the spring and summer, the leaves are full of chlorophyll, the chemical that converts sunlight into energy for the trees. Chlorophyll is the dominant pigment during the warm months and keeps the leaves looking green, hiding the other colors. But as the daylight hours shorten in the fall, and the colder weather arrives, then the production of chlorophyll decreases, and the yellow, orange and red pigments underneath are revealed.

Some years, the foliage is more brilliant than in other years. Often, this is due to the weather. The yellows and oranges are produced by carotenes, and the darker reds are produced by anthocyanin, which is only present in certain trees under certain conditions. The best weather conditions during the foliage season for the brightest colors are sunny days, with a daytime temperature above 50°, and nighttime temperatures in the 30s and low 40s.
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Why does it snow more in the mountains?
Clouds are formed when air rises, and then cools as it gains altitude. When the air temperature cools down to the dew point, the water vapor in the air will condense and form a cloud. And a cloud can drop rain or snow.

There are a few ways to get air to rise. An approaching cold front can push the air upwards. That is why it usually rains or snows when a cold front comes through. Also, air that is pushing together near the ground, called "low-level convergenge," has nowhere to go but up. And also, when the air is from the right direction, it can hit a mountainside, and the mountain itself forces the air to rise. This is called "orographic lift." So, the mountains can create their own weather by forcing air upwards, which then form clouds, which then drops rain or snow. Yet it can be dry in the valleys at the same time.
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