In 1995, three California Assembly members faced recalls. Each of these well-publicized elections drew from 25 percent to 35 percent of registered voters, well below the turnout for a general election. Similarly, the Michigan 1983 recalls saw a much smaller electorate. This isn't always the case, as Gray Davis actually had a much higher turnout than the 2002 election. The same thing happened in a non-recall setting with the special election of Scott Brown (higher turnout than 2006)
We saw in 2008 that if a recall takes place on a primary day, the advantage may be lost. Two state legislative recalls occurred on primary days that year (Speaker Andy Dillon in Michigan and Senator Jeff Denham in California). Both recalls were easily defeated.
Let's see what happens today. An increase in turnout may be a sign of the maturation of the recall.