What Day of the Week Was January 28, 1986?
January 28, 1986 was a Tuesday. On January 28, 1986, the Space Shuttle Challenger broke apart 73 seconds after launch from Kennedy Space Center in Florida, and its crew of seven died.
January 28, 1986 is a Tuesday
- Day of the year:
- day 28 of 365, 337 days left in the year
- Week number:
- ISO week 5 of 1986 · US week 5
- Weekday number:
- 3 in the US (Sunday = 1) · 2 in ISO 8601 (Monday = 1)
Another date? Change the date above, or open the day of the week calculator for today's weekday and any other date.
January 28, 1986 in numbers
| January 28, 1986 | |
|---|---|
| Day of the week | Tuesday |
| Weekday number | 3 in the US (Sunday = 1), 2 in ISO 8601 (Monday = 1) |
| Day of the year | 28 of 365, 337 days left |
| ISO week | Week 5 of 1986 |
| US week | Week 5 |
| Leap year | No, 1986 had 365 days |
| Julian Day Number | 2446459 |
January 1986 calendar
The whole month, with January 28, 1986 highlighted and the US federal holidays marked. The column on the left is the US week number.
| Wk | Su | Mo | Tu | We | Th | Fr | Sa |
|---|---|---|---|---|---|---|---|
| 1 | 1 (New Year's Day) | 2 | 3 | 4 | |||
| 2 | 5 | 6 | 7 | 8 | 9 | 10 | 11 |
| 3 | 12 | 13 | 14 | 15 | 16 | 17 | 18 |
| 4 | 19 | 20 (Martin Luther King Jr. Day) | 21 | 22 | 23 | 24 | 25 |
| 5 | 26 | 27 | 28 | 29 | 30 | 31 |
- 1 New Year's Day
- 20 Martin Luther King Jr. Day
The years 1947, 1958, 1969, 1975, 1997, 2003, 2014, 2025 have the same calendar as 1986: they start on the same weekday and are common years too, so January 28 is a Tuesday in each of them.
How to work out that January 28, 1986 was a Tuesday
Zeller's congruence gives the weekday of any Gregorian date with a few sums:
- Day q = 28; month m = 13 (January and February count as months 13 and 14 of the year before).
- Year of the century K = 85; century J = 19.
- q + ⌊13 × (m + 1) ÷ 5⌋ + K + ⌊K ÷ 4⌋ + ⌊J ÷ 4⌋ + 5 × J = 28 + 36 + 85 + 21 + 4 + 95 = 269.
- 269 divided by 7 leaves 3, and 3 stands for Tuesday (0 is Saturday, 1 Sunday, up to 6 for Friday).
DateMath's calculator gets the same answer another way, by counting the days from a fixed date and taking the remainder after whole weeks.
What day of the week is January 28 in the coming years?
| Date | Weekday | Since 1986 |
|---|---|---|
| January 28, 2027 | Thursday | 41 years |
| January 28, 2028 | Friday | 42 years |
| January 28, 2029 | Sunday | 43 years |
| January 28, 2030 | Monday | 44 years |
| January 28, 2031 | Tuesday | 45 years |
| January 28, 2032 | Wednesday | 46 years |
| January 28, 2033 | Friday | 47 years |
| January 28, 2034 | Saturday | 48 years |
| January 28, 2035 | Sunday | 49 years |
| January 28, 2036 | Monday | 50 years |
How DateMath finds the day of the week
DateMath counts the days from a fixed date to yours in the Gregorian calendar and takes the remainder after whole weeks, so every date in the years 1 to 9999 gets its weekday, leap days included. The same date is then numbered both ways: in the US, Sunday is day 1 of the week; in ISO 8601, Monday is day 1 and Sunday day 7. Today and tomorrow come from your device's date.
- The Gregorian calendar. DateMath treats every date as a Gregorian date, with its leap-year rule: a year divisible by 4 is a leap year, except century years not divisible by 400, so 2000 had a February 29 and 2100 will not. Source: Gregorian calendar.
- ISO 8601 week dates. DateMath numbers weeks by ISO 8601: weeks start on Monday, week 1 is the week with the year's first Thursday, and a year has 52 or 53 weeks. Source: ISO 8601.
DateMath's date math is tested against more than 100 cases worked out by hand. Every worked example and table on the site is computed with the same code the calculators run, so a page and its calculator can't disagree.
Frequently asked questions
- What day of the week was January 28, 1986?
- January 28, 1986 was a Tuesday. It was day 28 of 1986, in ISO week 5 and US week 5.
- What day of the week did the Challenger explode?
- On a Tuesday: January 28, 1986. Challenger launched from Kennedy Space Center at 11:38 AM Eastern Time that morning, after several delays earlier in the week.
- What day of the week is January 28 in 2027?
- January 28, 2027 is a Thursday. A date moves one weekday later each year, and two after a February 29.
- Was 1986 a leap year?
- No. 1986 had 365 days, so January 28, 1986 was day 28 of 365, with 337 days left in the year.