For many television viewers, May sweeps means a whole month of exciting moments before the summer reruns begin. The major networks pull out all of the best programming during May sweeps as they try to win the ratings war.

The month long special ratings period which features sitcoms, specials, movies and miniseries, is designed to set advertising rates in more than 200 cities.

Each year, the months of November, February, May, and July are known as the "sweeps" rating periods.

During sweeps, Nielsen ratings determine the audience size and composition of television programming in the United States. Set meters and People meters are the two types of meters used in the ratings process. Set meters capture what channel is being tuned, while People Meters go a step further and gather information about who is watching in addition to the channel tuned.

Diaries are also used to collect viewing information from sample homes in many television markets, and smaller markets are measured by paper diaries only.

This year, the ratings period for May begins Thursday, April 27 and ends Wednesday, May 24.

Here are a few highlights from the big four networks as they end the TV season with a bang.

(All times are Eastern)

ABC

Black-ish: Wednesday, May 10 at 9:30 p.m.

Once Upon a Time: Sunday, May 14 at 8 p.m. (2-hour finale)

Agents of S.H.I.E.L.D.: Tuesday, May 16 at 10 p.m.

Scandal: Thursday, May 18 at 9 p.m.

CBS

Blue Bloods: Friday, May 5 at 10 p.m.

Kevin Can Wait: Monday, May 8 at 8 p.m.

Superior Donuts: Monday, May 8 at 9 p.m.

Criminal Minds: Wednesday, May 10 at 9 p.m.

The Big Bang Theory: Thursday, May 11 at 8 p.m.

The Great Indoors: Thursday, May 11 at 8:30 p.m.

Mom: Thursday, May 11 at 9 p.m.

Life in Pieces: Thursday, May 11 at 9:30 p.m.

Hawaii Five-0: Friday, May 12 at 9 p.m.

NCIS: Los Angeles: Sunday, May 14 at 8 p.m.

Man With a Plan: Monday, May 15 at 8:30 p.m.

Scorpion: Monday, May 15 at 10 p.m.

NCIS: Tuesday, May 16 at 9 p.m.

NCIS: New Orleans: Tuesday, May 16 at 10 p.m.

Criminal Minds: Beyond Borders: Wednesday, May 17 at 9 p.m.

Undercover Boss: Friday, May 19 at 8 p.m.

Training Day: Saturday, May 20 at 9 p.m.

Madam Secretary: Sunday, May 21 at 9 p.m.

Elementary: Sunday, May 21 at 9 p.m.

Bull: Tuesday, May 23 at 8 p.m.

Survivor: Wednesday, May 24 at 8 p.m.

The CW

Riverdale: Thursday, May 11 at 9 p.m.

Supernatural: Thursday, May 18 at 8 p.m. (2-hour finale)

Supergirl: Monday, May 22 at 8 p.m.

Jane the Virgin: Monday, May 22 at 9 p.m.

The Flash: Tuesday, May 23 at 8 p.m.

Arrow: Wednesday, May 24 at 8 p.m.

The 100: Wednesday, May 24 at 9 p.m.

FOX

The Last Man On Earth: Sunday, May 7 at 9:30 p.m.

Brooklyn Nine-Nine: May 23 at 8 p.m.

Shots Fired: Wednesday, May 24 at 8 p.m.

Empire: Wednesday, May 24 at 9 p.m.

NBC

Taken: Monday, May 1 at 10 p.m.

Chicago Med: Thursday, May 11 at 9 p.m.

Chicago Justice: Sunday, May 14 at 9 p.m.

Chicago Fire: Tuesday, May 16 at 10 p.m.

Blindspot: Wednesday, May 17 at 8 p.m.

Chicago P.D.: Wednesday, May 17 at 10 p.m.

The Blacklist: Thursday, May 18 at 10 p.m.

Shades of Blue: Sunday, May 21 at 10 p.m.

The Voice: Tuesday, May 23 at 8 p.m.