Thinking about Primary Election Turnout
It's always a much lower percentage of registered voters than in the general election. Always. What does that mean? Well, when looking at poll results, it's very, very important to look at who is being polled. Unless those polled are "likely voters," it's not going to be that accurate, generally. If the poll queries "registered voters," many of those people will not vote in the primary election, if history is any guide at all.
Generally, voters in primary elections are dedicated members of the political party that the ballot in closed primaries represents. Sometimes voters don't usually participate. Turnout in primary elections is generally only a fraction of that in a general election. So, you can bet that almost everyone who casts their ballot is a Democrat who always votes in every election. Sadly, there are too few of those.
So, pay close attention to the group being polled in any primary poll. It makes a big difference in the accuracy of that poll.