Why flags are flying at half-staff, half-mast at Ohio, U.S. buildings today?

Ohio Gov. Mike DeWine announced all flags on public grounds will be flown at half-staff on Monday to mark Patriot Day In honor of those killed in the terrorist attacks on September 11, 2001.

When did Patriot Day start?

According to Wikipedia:

From 2009 to 2016, President Barack Obama proclaimed September 11 as Patriot Day and National Day of Service and Remembrance, in observance of the Edward M. Kennedy Serve America Act. In 2017, President Donald Trump proclaimed September 8–10 as National Days of Prayer and Remembrance and proclaimed September 11 as Patriot Day. President Trump also did so in 2018, 2019, and 2020 as well. After Joe Biden was elected president in 2021, he also issued an Executive Order for Patriot Day 2021 and Patriot Day 2022.

What does half-staff mean?

When a flag is lowered to the middle of the pole, it remembers a sorrowful event or anniversary that impacted the public.

Half-staff always refers to the lowering of a flag. In contrast, half-mast refers to naval ships, according to the Naval History blog and the U.S. Department of Veterans Affairs.

When flags are ordered to be lowered at half-staff, they should stay at that designated height for 30 days unless the order specifies a sooner date.

When are flags lowered throughout the year?

Flags on public building throughout the United States are routinely flying at half-staff on these additional dates:

May 15 - Peace Officers Memorial Day (half-staff all day)

Sept. 11 - Patriot Day (half-staff all day)

First Sunday in October - Fallen Fighters Fallen Firefighters (half-staff all day)

Dec. 7 - Pearl Harbor Remembrance Day (half-staff all day)