Answer:  While most hiring managers think their timetable to complete a search is unique, it is subject to the realities of when decision-makers have time to complete the process and extend an offer. There really is a cycle.
Here is a blog post about activities for the months of March and April which is generally the interview phase of the primary annual hiring cycle.

CALENDAR – March & April.
EVENTS – Easter Sunday and Passover; Spring Break which varies from region to region and the Trade Show Season swings into high gear.

We are now into March and these first-round interviews usually wrap up toward the end of March. At that point, the number of candidates is narrowed down to 5 or less. Another round of interviews is scheduled for early April (and perhaps late March) depending upon travel schedules. The goal is to select 3 finalists. During this phase schedules become complicated. If the hiring organization can arrange a day or two when the interviewing team can meet candidates, and the candidates are free those days as well, the timetable will work. Otherwise, delays occur that can mean the final round of interviews occur in late April or early May.

As a motivated and cooperative candidate, you should be anticipating every step in the process and providing as much information about your timetable and interest as possible. You should have a phone number that is reserved for calls related to your search efforts and that should be “at the ready” along with a personal email that you check several times a day. Most contact is via email or phone, but texting is becoming more common. Email is safer since that provides a record of conversations. Thank you notes should be sent to all the people that interviewed you.

Providing scheduling information in writing is considered helpful. You can also ask how many candidates are under consideration as you proceed through the hiring process. That is as far as you can go; any other details are considered confidential. Your objective is to facilitate the screening process and establish a pattern of behavior that is responsible, responsive and trustworthy.