# https://altair-viz.github.io/gallery/scatter_with_rolling_mean.html

import altair as alt
from vega_datasets import data

source = data.seattle_weather()

line = (
    alt.Chart(source)
    .mark_line(color="red", size=3)
    .transform_window(
        rolling_mean="mean(temp_max)",
        # sort=[{"field": "date"}],  # Shouldn't need this
        frame=[-15, 15],
    )
    .encode(x="date:T", y="rolling_mean:Q")
)

points = (
    alt.Chart(source)
    .mark_point()
    .encode(x="date:T", y=alt.Y("temp_max:Q", axis=alt.Axis(title="Max Temp")))
)

points + line
