How to check if a date is within a certain range?

I am writing a program to help manage my fantasy football league. As a part of this, I need to identify what week of play we're in. For those that aren't familiar, fantasy football weeks don't line up to standard weeks, each fantasy week starts on a Tuesday, and ends the following Monday.

I'm a novice at Python, and I've written code that accomplishes what I want to do, but I'm sure there's a better way of doing it. I'm curious what a better way to go about this would be in the future. In particular, I'd love to not have to change each of these variables every single season.

import datetime

timenow = datetime.datetime.now().date()
week1start = datetime.date(day=9, month=9, year=2021)
week1end = datetime.date(day=13, month=9, year=2021)
week2start = datetime.date(day=14, month=9, year=2021)
week2end = datetime.date(day=20, month=9, year=2021)
week3start = datetime.date(day=21, month=9, year=2021)
week3end = datetime.date(day=27, month=9, year=2021)
week4start = datetime.date(day=28, month=9, year=2021)
week4end = datetime.date(day=4, month=10, year=2021)
week5start = datetime.date(day=5, month=10, year=2021)
week5end = datetime.date(day=11, month=10, year=2021)
week6start = datetime.date(day=12, month=10, year=2021)
week6end = datetime.date(day=18, month=10, year=2021)
week7start = datetime.date(day=19, month=10, year=2021)
week7end = datetime.date(day=25, month=10, year=2021)
week8start = datetime.date(day=26, month=10, year=2021)
week8end = datetime.date(day=1, month=11, year=2021)
week9start = datetime.date(day=2, month=11, year=2021)
week9end = datetime.date(day=8, month=11, year=2021)
week10start = datetime.date(day=9, month=11, year=2021)
week10end = datetime.date(day=15, month=11, year=2021)
week11start = datetime.date(day=16, month=11, year=2021)
week11end = datetime.date(day=22, month=11, year=2021)
week12start = datetime.date(day=23, month=11, year=2021)
week12end = datetime.date(day=29, month=11, year=2021)
week13start = datetime.date(day=30, month=11, year=2021)
week13end = datetime.date(day=6, month=12, year=2021)
week14start = datetime.date(day=7, month=12, year=2021)
week14end = datetime.date(day=13, month=12, year=2021)
week15start = datetime.date(day=14, month=12, year=2021)
week15end = datetime.date(day=20, month=12, year=2021)
week16start = datetime.date(day=21, month=12, year=2021)
week16end = datetime.date(day=27, month=12, year=2021)


def get_current_week():
    if timenow < week1start:
        return 0
    elif week1start <= timenow <= week1end:
        return 1
    elif week2start <= timenow <= week2end:
        return 2
    elif week3start <= timenow <= week3end:
        return 3
    elif week4start <= timenow <= week4end:
        return 4
    elif week5start <= timenow <= week5end:
        return 5
    elif week6start <= timenow <= week6end:
        return 6
    elif week7start <= timenow <= week7end:
        return 7
    elif week8start <= timenow <= week8end:
        return 8
    elif week9start <= timenow <= week9end:
        return 9
    elif week10start <= timenow <= week10end:
        return 10
    elif week11start <= timenow <= week11end:
        return 11
    elif week12start <= timenow <= week12end:
        return 12
    elif week13start <= timenow <= week13end:
        return 13
    elif week14start <= timenow <= week14end:
        return 14
    elif week15start <= timenow <= week15end:
        return 15
    elif week16start <= timenow <= week16end:
        return 16