Historical clue formulations

• Celebration between Xmas and M.L.K. Day — 2026-09-13
• 365th out of 365, in brief — 2026-08-14
• Science guy Bill — 2026-04-23
• Bill who says "Science rules!" in the intro to his TV show — 2026-02-09
• What comes before 1/1 — 2025-09-27
• 12/31 — 2025-05-18
• Countdown occasion, for short — 2025-04-26
• Scientific Bill — 2025-01-14
• 12/31 — 2025-01-01
• Dec. 31, in brief — 2024-11-04
• Bill ___, the Science Guy — 2024-10-01
• Bill supporting public television — 2024-02-15
• Time to drop the ball, in brief — 2024-01-19
• Bill concerned with science communication — 2023-12-15
• It ends when 1/1 begins — 2023-11-19
• Bill of science — 2023-08-18
• Bill advocating for science — 2023-04-26
• Bill promoting science — 2022-09-30
• December 31, for short — 2022-05-02
• Bill known as the "Science Guy" — 2022-01-24
• Dec. 31 — 2021-09-16
• Time for a countdown: Abbr. — 2021-07-23
• Nevada's largest county — 2021-06-22
• 12/31 — 2021-01-01
• Dec. 31 celebration — 2020-10-07
• Bill, the Science Guy — 2020-10-05
• Day when the ball drops: Abbr. — 2020-08-29
• TV's "Science Guy" — 2020-07-23
• December 31, in brief — 2020-06-24
• Science educator Bill — 2020-05-19
• "Bill ___ Saves the World" — 2020-03-26
• Dec. 31 — 2020-01-25
• "Science Guy" Bill — 2019-11-26
• 12/31, briefly — 2019-10-21
• Nevada's largest county by area — 2019-05-12
• Countdown time, for short — 2019-04-14
• Bill of the Planetary Society — 2019-04-06
• The Science Guy — 2019-03-17
• Netflix's "Bill ___ Saves the World" — 2019-02-25
• Bill ___, the Science Guy — 2018-08-21
• December 31: Abbr. — 2017-12-31
• Bill ___, the Science Guy — 2017-08-16
• Bill who's a science expert — 2017-06-26
• C.E.O. of the Planetary Society starting in 2010 — 2017-05-28
• Bill who popularizes science — 2017-04-11
• "Science Guy" Bill — 2017-02-27
• Bill ___, the Science Guy — 2017-02-20
• Former PBS host with a bow tie — 2016-11-23
• Bill ___, the Science Guy — 2016-10-11
• Host of the web series "Emoji Science" — 2016-09-09