What Day: September 21
Find the day of the week for any date of the year.
September 21 this year (2026) falls on a Monday. It's day 264 of the year, with 101 days left afterward, sits in Q3 (Fall), and falls under the zodiac sign Virgo in Western astrology. Because of how leap years shift the calendar, a date's day-of-week doesn't repeat on a fixed yearly schedule. September 21 will next fall on a Monday again in 2037. Within September, this is day 21 of 30, roughly 70% through the month. Overall, that's roughly 72% of the way through the year.
As of October 1, 2026, 12:19 PM (America/New York).
A Decade Ago
September 21, 2016 fell on a Wednesday, a useful reference point if you're comparing how a recurring event has shifted across the week over the years.
Half a Year Away
Roughly six months from September 21 is March 21, which falls in spring and lands on a Saturday this year.
Nearby Dates
Check the day of the week for the date just before or after September 21 using the links below.