His likely Republican rival, George Allen, had raised $1.1 million in that same period and finished with $2 million in the bank.
Kaine has raised more than Allen in a shorter period of time, and had a $1.3 million advantage coming into the election year.
Since the campaign kicked off in April, Kaine has raised more than $5.2 million from more than 12,000 supporters. Allen raised $4.5 million last year.
“All signs point to a record-breaking year of spending by outside groups, which makes it even more gratifying that we’ve been able to attract so much grassroots enthusiasm and financial support for our campaign,’’ Kaine said.
Kaine and Allen — both former governors — are vying to succeed retiring Sen. James Webb (D).