According to the Gregorian calendar, what day of the week falls on 18th February 2016?

Introduction / Context:
Day-of-week problems for given dates test your ability to apply calendar rules or known references. Here, you are asked to identify the day of the week on 18 February 2016. Since 2016 is a leap year, February has 29 days, which influences offsets relative to nearby dates.

Given Data / Assumptions:

Date of interest: 18 February 2016.

Year 2016 is a leap year because it is divisible by 4 and not a century year.

We assume the standard Gregorian calendar.

We can use a known reference or algorithm (for example, that 1 January 2016 was a Friday) and then count forward.

Concept / Approach:
One straightforward method is to start from a known weekday, such as 1 January 2016, and then count days forward to 18 February, using modulo 7 to get the net weekday shift. 2016 being a leap year does not change this approach; it simply defines that February has 29 days, which helps with counting later dates in the month.

Step-by-Step Solution:
Step 1: Use the known reference. 1 January 2016 is known to be a Friday. Step 2: Count days from 1 January to 18 February 2016. Days in January after 1 January: 30 days (from 2nd to 31st). Total days in January including 1st: 31, but for weekday shifting from 1 January we consider 17 days into February plus all of January after the 1st. Days from 1 January to 31 January inclusive is 31 days. Then days from 1 February to 18 February inclusive is 18 days. Total days from 1 January to 18 February inclusive = 31 + 18 = 49 days. To move from 1 January to 18 February, we move forward 48 days (since 1 January is day 1). Step 3: Reduce this forward shift modulo 7. 48 divided by 7 gives 6 full weeks and a remainder of 6 days (48 mod 7 = 6). So we move 6 weekdays forward from Friday. Step 4: Shift the weekday. Starting at Friday, moving 6 days forward: Saturday (1), Sunday (2), Monday (3), Tuesday (4), Wednesday (5), Thursday (6). Thus, 18 February 2016 falls on a Thursday.

Verification / Alternative check:
You can instead calculate directly using a day-of-week algorithm such as Zeller’s congruence or use the fact that 29 February 2016 is a Monday and adjust backward. Both methods give Thursday as the weekday for 18 February 2016. The modular arithmetic method based on a known reference is simple and consistent for exam problems.

Why Other Options Are Wrong:
Friday or Saturday would require a different remainder when dividing the number of days by 7, which is not supported by the 48-day shift. Wednesday is one day earlier than Thursday and would correspond to a shift of 5 days instead of 6. None of these match the precise calculation.

Common Pitfalls:
Errors often occur when including or excluding the starting date incorrectly or miscounting the days in January and February. Another common mistake is forgetting that 2016 is a leap year, but that mostly affects dates after February; for the 18th, the key is accurate day counting. Carefully performing the calculation and then taking modulo 7 avoids these issues.

Final Answer:
18 February 2016 was a Thursday.