"April is a reminder of the seasonality of sports betting, and Virginia is not immune," said Jessica Welman, analyst for the PlayUSA.com Network, which includes PlayVirginia.com. "In the U.S., there really isn't any way to replace the popularity of the NFL or the NCAA Tournament with bettors. The seasonal slowdown should last until football season, which will almost certainly return the market to significant growth."

Virginia sportsbooks attracted $236.4 million in bets in April, according to data released Friday by The Virginia Lottery. That is down 22.2% from $304.1 million in March and the lowest monthly handle of any of Virginia's first full three months of sports betting. With no major sports holiday to spur interest, sportsbooks took in $7.9 million per day over the 30 days in April, down from $9.8 million in March.

Sportsbooks still won $19.4 million on April's bets, down from $26.6 million in March. April's win led to $11.4 million in adjusted gross revenue, down from $13.8 million but still a higher share of gross revenue than in March. That yielded $1.7 million in state taxes, including $41,304 for problem gambling support.

Every state with legal sports betting has reported a month-over-month decline in April wagering. Of the largest sports betting markets in the U.S. that have already reported April data, Indiana (-25.4%), Iowa (-26.7%), and Michigan (-30.5%) all experienced a more dramatic month-over-month decline than Virginia. New Jersey (-13%), Tennessee (-13.6%), Pennsylvania (-14.4%), and Colorado (-18.8%) were better.

"The lighter sports schedule came at a time when the initial enthusiasm from the launch of sports betting naturally began to wane in Virginia, which steepened the monthly decline," said Dustin Gouker, analyst for PlayVirginia.com and the PlayUSA.com Network. "Still revenue held relatively strong, producing the most tax revenue to date for the commonwealth. That is a good sign heading into summer."

Now with $865.2 million in wagering since launching in late January, Virginia is still on the precipice of becoming the quickest state to reach the $1 billion milestone. That distinction is currently held by Tennessee, which reached the mark six months after launch. Assuming Virginia can top $135 million in bets in May, it will have hit $1 billion in the market's fifth month of existence.

Even more, Virginia could see a modest boost in the coming months from the NBA playoffs lasting deeper into summer than normal and the Olympics. And more operators are still expected to launch before the beginning of football season, including the expected addition of Penn National's highly popular Barstool-branded app.

"Virginia's market remains in an excellent position," Welman said. "In fact, Virginia stands should be able to avoid the worst of the typical summer swoon, which will really set the market up for a huge fall."