His annual prediction was translated by his handlers at Gobbler's Knob in the US state of Pennsylvania.
The Punxsutawney Groundhog Club says that when Phil is deemed to have not seen his shadow, that means there will be an early spring.
When he does see it, it is six more weeks of winter.
Phil tends to predict a longer winter far more often than an early spring.
Tens of thousands of people were on hand at Gobbler's Knob for the annual ritual that goes back more than a century, with ties to ancient farming traditions in Europe.
Punxsutawney's festivities have grown considerably since the 1993 movie Groundhog Day, starring Bill Murray.
Lisa Gibson was at her 10th Groundhog Day, wearing a lighted hat that resembled the tree stump from which Phil emerges shortly after daybreak.
"Oh man, it just breaks up the doldrums of winter," said Gibson, accompanied by her husband - dressed up as Elvis Presley - and teenage daughter.
"It's like Halloween and New Year's Eve all wrapped up into one holiday."
Gibson, a resident of Pittsburgh, had been rooting for Phil to not see his shadow and therefore predict an early start to spring.
Rick Siger, Pennsylvania's secretary of community and economic development, said the outdoor thermometer in his vehicle read minus 15C on his way to Gobbler's Knob.
"I think it's just fun - folks having a good time," said Siger, attending his fourth straight Groundhog Day in Punxsutawney.
"It brings people together at a challenging time. It is a unifying force that showcases the best of Pennsylvania, the best of Punxsutawney, this area."
Last year's announcement was six more weeks of winter, by far Phil's more common assessment and not much of a surprise during the first week of February.
His top-hatted handlers in the Punxsutawney Groundhog Club insist Phil's "groundhogese" of winks, purrs, chatters and nods are being interpreted when they relate the meteorological marmot's muses about the days ahead.
AccuWeather's chief long-range weather expert, meteorologist Paul Pastelok, said early on Monday some clouds moved into Punxsutawney overnight, bringing flurries he called "microflakes".
Pastelok said the coming week will remain cold, with below-average temperatures in the eastern United States.
Phil isn't the only animal being consulted for long-term weather forecasts on Monday.
There are formal and informal Groundhog Day events in many places in the US, Canada and beyond.
Groundhog Day falls on February 2, the midpoint in the northern hemisphere between the shortest, darkest day of the year on the winter solstice and the spring equinox.
It is a time of year that also figures in the Celtic calendar and the Christian holiday of Candlemas.
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