You can find seats for this fare starting later this week for travel through early June, July travel is blacked-out, but the airfare reappears from late August through September at this price. Travel is valid for midweek travel, but you will find an occasional day on the weekend or Friday that is available. It's an excellent price drop on this particular route as other airlines are charging over $100 more for the same city pairing.
Searching on United's website, I found seats departing SJC on Sunday, May 27, and returning from MCO on Monday, June 4, 2018.
Have a look at a full list of departure deals we have on the San Jose (SJC) flight deals page.
If you need a room while visiting Orlando, here's a full list of available options for the mentioned travel dates above on Hotelwatchdog.