"The winter has been extraordinarily difficult. And barring major breakthroughs in the region, spring will be difficult," he told a press briefing at the presidential palace several hours before leaving on a four-day official visit to the United States.
Ghani, who came to power in September, said he had not asked for any specific aid from the United States nor any changes to planned troop withdrawals.
"What I'll be explaining to the Congress of the United States is what we're doing. What we're underlining is both the nature of the threat and what we're doing with the existing resources and capabilities," he said.
The United States was due to reduce its 10,000 troops to 5,500 by December, but that number is expected to be reassessed.
Also Read
The Afghan government has been "actively engaging" with its neighbours in the region over the past few weeks "from Azerbaijan to India" to create conditions for discussions with the Taliban, Ghani said.
"We have not had face-to-face discussions, we're preparing the conditions for those," he added.
Diplomatic efforts to bring the Taliban to the negotiating table have gained pace recently, even as security forces have launched offensives against the insurgent group without NATO assistance for the first time since 2002.
Ghani and his Chief Executive Abdullah Abdullah will have the opportunity on their US visit to discuss the emergence of the Islamic State group (IS).
Ghani said IS "swallows its competitors".
"If you compare Al Qaeda and Daesh, it's like going from Windows 1 to Windows 5," he said, referring to IS by an alternative name.
"These groups do not fit with the classic insurgency."
The Middle East-based group has not formally confirmed it is operating out of Afghanistan, though Pakistani and Afghan commanders have pledged their allegiance to the outfit in recent months.
But he stressed he considers neighbouring Pakistan a key partner in the peace process, saying success depends on "an enduring peace" with Islamabad.