[Python] Second independent axis in Altair

I would like to add a second (independent) x-axis to my figure, demonstrating a month for a given week.

Here is my snippet:

import pandas as pd
import numpy as np
from datetime import datetime, timedelta

weeks = list(range(0, 54))
start_date = datetime(1979, 1, 1)
week_dates = [start_date + timedelta(weeks=w) for w in weeks]

years = list(range(1979, 2024))
data = {
"week": weeks,
"date": week_dates,
"month": [date.strftime("%b") for date in week_dates],
}
# Precipitation
data.update({str(year): np.random.uniform(0, 100, size=len(weeks)) for year in years})
df = pd.DataFrame(data)
df["Mean_Precipitation"] = df[[str(year) for year in years]].mean(axis=1)

rain_calendar = alt.Chart(df, title=f"Weekly precipitation volumes").mark_bar().encode(
alt.X('week:O', title='Week in calendar year', axis=alt.Axis(labelAlign="right", labelAngle=-45)),
alt.Y(f'1979:Q', title='Rain'),
alt.Color(f"1979:Q", scale=alt.Scale(scheme='redyellowgreen')),
alt.Order(f"1979:Q", sort="ascending")).properties(width=850, height=350)

line = alt.Chart(df).mark_line(interpolate='basis', strokeWidth=2, color='#FB0000').encode(
alt.X('week:O'),
alt.Y('Mean_Precipitation:Q'))

month_labels = alt.Chart(df).mark_text(
align='center', baseline='top', dy=30
).encode(
alt.X('week:O', title=None), text='month:N')

combined_chart = alt.layer(rain_calendar, line, month_labels).resolve_scale(x='shared').configure_axisX(
labelAlign="right", labelAngle=-45, titlePadding=10, titleFontSize=14)\
.configure_axisY(titlePadding=10, titleFontSize=14).configure_bar(binSpacing=0)


So far, this is the best outcome that I've got:



It is a topic related to discussed one there: Second x axis or x labels

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