The weather forecast for Philly calls for no rain and is approaching century-old records

While Philly can't quite match the Northern Lights or the appearance of an 80,000-year comet, it has an excellent chance of breaking rainless records that have stood since the administrations of Ulysses S. Grant and Calvin Coolidge.

It's been 23 days since a raindrop was officially observed at Philadelphia International Airport, and the latest forecasts for the period leading up to Election Day call for little, if any, precipitation.

The current record for most consecutive days without rain is 29, set in October and November 1874, a few years after Grant signed a bill creating a National Weather Service and Philly began recording weather data. This month also has a chance to dethrone the all-time drought winners of October 1924 and 1963, when a full 0.09 inches were officially recorded in each of those months. These also remain the driest months on record – but perhaps not for long.

Combined, September and October will most likely be the driest two-month period on record.

Why doesn't it rain in Philly?

Rainy Octobers are nothing new here. “This is typically a dry season in many areas,” said Frank Pereira, senior meteorologist at the government's Weather Prediction Center in College Park, Maryland.

But drought is another matter. In fact, the air in Philly has been just as dry in recent days as it has been in Phoenix, which has had – a touch – more rain this month than in Philadelphia.

A number of fronts have been moving through the Northeast and Mid-Atlantic regions, but in terms of rain production, they've essentially been trying to suck moisture out of the dry rags.

Rain-defying high pressure — heavier, sinking air that has smothered clouds and brought a remarkable series of unrelenting blue skies over the Philly region, along with a spectacular moonlight display last week — has dominated the weather agenda in Philadelphia and much of the U.S. East.

“That’s pretty much the pattern we’re stuck in right now,” Pereira said. “It looks like it’s going to stay that way.”

Ironically, a recent series of tropical storms has also contributed to the drought, according to meteorologists. In part, the sinking air that deprived the Philly region of moisture was a response to the rain-bearing rising air that accompanied these storms.

As for possible links to climate change, droughts are expected to become more frequent as temperatures rise. However, the Intergovernmental Panel on Climate Change has said that warming has not yet reached a level at which the eastern United States would be “affected by an increase in agricultural and environmental droughts.”

Urging residents to conserve water, New Jersey declared a statewide drought warning Thursday, a step Pennsylvania has not yet taken. The Philadelphia region has not experienced a significant drought in over 20 years.

Conditions here were desert-like, with daytime humidity similar to Phoenix. One symptom of the drought is the difference between nighttime lows and daytime highs in Philly. With rapid cooling at night, the average temperature has been around 25 degrees since October 10th.

Clear skies following increasingly earlier sunsets have allowed daytime heat to escape efficiently into space, particularly in areas away from Philly's urban heat island, said Ray Martin, senior meteorologist at the National Weather Service's Mount Holly office. In Millville, for example, the day-night differences were on the order of 30 to 40 degrees.

Bushfires are likely to be a growing threat and the weather service is warning that the dry spell could eventually lead to widespread drought impacts.

But now the drought has some obvious benefits. Just ask the campers and hikers. Foliage experts say the cool nights have been great for fall colors. (Eat your heart out, Phoenix.)

And while the last two days have been particularly warm – 81 degrees on Monday and a record-breaking 84 degrees on Tuesday – the higher temperatures that may have been uncomfortable for some lasted only a few hours, Dave Dombek, senior meteorologist at AccuWeather Inc. said on Am On July 6, however, the temperature never fell below 80 degrees, while on one day it rose to 97 degrees.

In addition, the region is fortunate that nature turned off the tap at a time when the foliage is preparing for the season, Dombek said

If a dry spell like this parched the region in the summer, when water needs for people and vegetation are higher, “we would be in serious trouble,” he said.

Will it ever rain again in Philly?

The Climate Prediction Center expects rainfall to be below normal through Election Day.

In the short term, no decline in the forecast is expected until Monday. So it appears Philly is on track to break the record for consecutive days without rain.

And it's entirely possible that October ends at midnight.

That would be a record that could never be broken.