January 20, 2042 (Monday) to January 26, 2042 (Sunday)
Week 4 of 2042 runs from January 20, 2042 (Monday) to January 26, 2042 (Sunday). This is the 4th week of the year according to the ISO 8601 standard, in which weeks start on Monday.
Jan 20 is a Monday. It is the first day of Week 4 of 2042.
Jan 26 is a Sunday. It is the last day of Week 4 of 2042.
Jan 20 is in Week 4 of 2042 according to ISO 8601.
Jan 26 is in Week 4 of 2042 according to ISO 8601.
Week 4 of 2042 runs from January 20, 2042 to January 26, 2042.
Week 4 of 2042 starts on January 20, 2042, the 20th day of 2042.
Yes, all 7 days of Week 4 of 2042 fall within 2042.
2042 has 52 weeks according to ISO 8601.