Here is a bit of Iowa Code:
43.4 POLITICAL PARTY PRECINCT CAUCUSES.
Delegates to county conventions of political parties and party committee members shall be elected at precinct caucuses held not later than the fourth Monday in February of each even-numbered year.
The date shall be at least eight days earlier than the scheduled date for any meeting, caucus, or primary which constitutes the first determining stage of the presidential nominating process in any other state, territory, or any other group which has the authority to select delegates in the presidential nomination.
Thank you for the cite.
Thanks