Raindrops impact at their terminal velocity, which is greater for larger drops. At sea level and without wind, 0.5 mm drizzle impacts at about 2 m/s, while large 5 mm drops impact at around 9 m/s.^[4] The sound of raindrops hitting water is caused by bubbles of air oscillating underwater. See droplet's sound.

Generally, rain has a pH slightly under 6. This is because atmospheric carbon dioxide dissolves in the droplet to form minute quantities of carbonic acid, which then partially dissociates, lowering the pH. In some desert areas, airborne dust contains enough calcium carbonate to counter the natural acidity of precipitation, and rainfall can be neutral or even alkaline. Rain below pH 5.6 is considered acid rain.

Effect on agriculture

Precipitation, especially rain, has a dramatic effect on agriculture. All plants need at least some water to survive, therefore rain (being the most effective means of watering) is important to agriculture. While a regular rain pattern is usually vital to healthy plants, too much or too little rainfall can be harmful, even devastating to crops. Drought can kill crops in massive numbers, while overly wet weather can cause disease and harmful fungus. Plants need varying amounts of rainfall to survive. For example, cacti need small amounts of water while tropical plants may need up to hundreds of inches of rain per year to survive.

Agriculture of all nations at least to some extent is dependent on rain. Indian agriculture, for example, (which accounts for 25 percent of the GDP and employs 70 percent of the nation's population) is heavily dependent on the rains, especially crops like cotton, rice, oilseeds and coarse grains. A delay of a few days in the arrival of the monsoon can, and does, badly affect the economy, as evidenced in the numerous droughts in India in the 90s.

Culture

Rain on an umbrella from passing showers

Cultural attitudes towards rain differ across the world. In the largely temperate Europe, rain metaphorically has a sad and negative connotation — reflected in children's rhymes like Rain Rain Go Away — in contrast to the bright and happy sun. Though the traditional notion of rain in the Western World is negative, rain can also bring joy, as some consider it to be soothing or enjoy the aesthetic appeal of it. In dry places, such as parts of Africa, Australia, India, the Western United States, and the Middle East, rain is greeted with euphoria. (In Botswana, the Setswana word for rain, "pula," is used as the name of the national currency, in recognition of the economic importance of rain in this desert country.)

Several cultures have developed means of dealing with rain and have developed numerous protection devices such as umbrellas and raincoats, and diversion devices such as gutters and storm drains that lead rains to sewers. Many people also prefer to stay inside on rainy days, especially in tropical climates where rain is usually accompanied by thunderstorms or is extremely heavy (as in a monsoon). Rain may be harvested, though rainwater is rarely pure (as acid rain occurs naturally), or used as greywater. Excessive rain, particularly after a dry period that has hardened the soil so that it cannot absorb water, can cause flood

Many people find the scent during and immediately after rain especially pleasant or distinctive. The source of this scent is petrichor, an oil produced by plants, then absorbed by rocks and soil, and later released into the air during rainfall. Light or heavy rain is sometimes seen as romantic.

Weather forecast services are available at Dubai with the help of Aviation Weather Decision Support System (AWDSS) that provides automated and extremely detailed, immediate forecasts on meteorological conditions for the aviation industry.

Dubai weather average

The average climatic condition of Dubai promises sunshine with very little amount of rainfall. Summers are hot and strong sea breezes are experienced though rainfall is scanty and unusual. During winter the weather is warm and sunny with an average moderate temperature. The mean rainfall is 6.5cm per year and it rains only for five days a year on an average.

Dubai weather year round

Summers in Dubai are extremely hot with very scanty and erratic rainfall. June to September is marked as the hottest months, when temperatures climb upward during the day. The humidity levels are also very high with an increased sea temperature. The rest of the year, weather condition is a bit more moderate. The coolest time is between December to March. Rainfalls are common in winters. In Dubai, the minimum temperature is generally experienced in the month of January and it seldom goes below 12°C.

Dubai weather conditions

Dubai experiences a dry subtropical climate characterized with clear blue skies and sunshine, and summer storm. Dubai city weather observes diverse types of winds blowing across the desert. The first major Shamal which occurs around May 25th is characterized by mild north-westerly breeze and is known as the Al-Haffar. The second that arrives in early June, is called Barih Thorayya. Al-Dabaran, the last Shamal, arrives by the end of June.

Dubai weather temperature

The average temperate of Dubai rises to mid 40s during summer. Sea temperature is approximately 37°C. The temperature often ranges between 430C to 48°C in the hottest months of July and August. The winters of Dubai are very comfortable and pleasant with a mean maximum temperature of 24°C and lowest temperature of more or less 150C.

Dubai weather monthly

January is the coolest month with a cloudy weather, while February is the wettest with a moderate temperature. March to May indicates spring with a constant rise in temperature. The climatic condition in June is hot and dry. July and August are characterized with extreme hot and summer storms. September is the highest humid month of summer, whereas October, November, and December are pleasant and experience rainfall.

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Temperatures that dipped into the teens on Friday are expected to rise to the upper 30s to lower 40s on Saturday, the weather service said.

Larry Holeman, deputy emergency management director of rural Grayson County, called his hard-hit community "a war zone."

The emergency reflects the challenges faced in states such as Kentucky, where many rural and remote regions struggle to keep warm and dry under dire weather conditions.

Nine weather-related deaths have been reported, with two confirmed, said the office of Gov. Steve Beshear. A previously confirmed death has since been found to be unrelated to the weather.

In western Louisville, three adults were found dead Friday morning of apparent carbon monoxide poisoning from a generator the family brought indoors, Mayor Jerry Abramson said.

The deaths prompted authorities to issue a stern warning about the dangers of carbon monoxide.

"We've lost three citizens because people weren't listening to the fire department when they look into the cameras and talk on the radios and say, 'listen up, carbon monoxide kills,' " Abramson said in a press conference Friday afternoon. "We can't talk enough about it."

The storm caused the largest power outage in Kentucky's history, with more than 607,000 customers out of power. Watch residents of Grayson County, Kentucky, try to cope with outage »

But Melnykovych said that while the state is saying 607,000 customers have lost power, he thinks the number is closer to 650,000 because the state figure comes only from utilities it regulates.

When Hurricane Ike hit in September, 600,000 customers lost power. Melnykovych said the temperature was around 75 degrees and power outages were more of an "inconvenience than a life-threatening situation." iReport.com: Send your wintry weather photos, videos

"Hurricane Ike didn't have this kind of impact," he said.

Of the state's 120 counties, 78 have declared emergencies. So have 47 cities, the governor's office said.

At least 113 emergency shelters have been opened.

Jewel Tomes, who lives in Leitchfield, took shelter at a high school after a complex for the elderly lost power and was "thrilled to have a place to come to."

"The high school here was generous, and more than 500 people have been sheltered here, and we have had cots and blankets and three meals a day. And we had medication," she said.

Around 93,000 customers on 55 water systems remain without access to water because of outages and storm damage. Photos of storm's impact »

Crews across the state were working to clear roads of snow, ice and trees.

A key concern is getting generators to water treatment facilities because of the large number of people without water.

The Kentucky National Guard, which has had 620 soldiers on duty, is bolstering to 1,000 the number of soldiers aiding recovery efforts.

Three of the battalions are headed to Paducah, Owensboro and Benton in the west and others are headed to other hard-hit spots.

The state said the Federal Emergency Management Agency will operate out of a National Guard center in Frankfort.

Beshear praised the Obama administration's prompt reaction to the storm.

"They really hit the ground running," he said. "They're working very hard to get all the equipment and supplies here that we need."

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