Mean overlay over precipitation chart
View this example in the online editor
Vega-Lite JSON Specification
{
"$schema": "https://vega.github.io/schema/vega-lite/v3.json",
"data": {"url": "data/seattle-weather.csv"},
"layer": [
{
"mark": "bar",
"encoding": {
"x": {
"timeUnit": "month",
"field": "date",
"type": "ordinal"
},
"y": {
"aggregate": "mean",
"field": "precipitation",
"type": "quantitative"
}
}
},
{
"mark": "rule",
"encoding": {
"y": {
"aggregate": "mean",
"field": "precipitation",
"type": "quantitative"
},
"color": {"value": "red"},
"size": {"value": 3}
}
}
]
}