CALENDAR HEATMAP

weekday x week grid, shaded and numbered. Needs: a count or measure per weekday per week; the weekly rhythm is the message.

patternchange-over-timedensity

DL-01 AGRAW

Use when

workload rhythm: deliveries, tickets, tests per weekday across weeks
capacity planning around recurring peaks

Do not use when

non-calendar dimensions (CH-COR-03)
single week (a column chart does it)

See instead

dimensions are not calendar units: CH-COR-03

Alternatives

CH-COR-03 (generic two-dimension grids)

Rules

weekday rows in calendar order, always
values printed in every cell
single-hue ramp; global normalization

Never do this

sorting weekdays by value
rainbow ramps
cells without values

QA before delivering

weekday order fixed
every cell numbered
title names the rhythm
source present

Data shape

title	action title naming the rhythm
source	bottom-left always
columns	week labels
rows	weekday rows {label, values[]}

Sample data (golden)

{
  "title": "Volume builds through July and Thursdays stay the peak day",
  "eyebrow": "DELIVERIES . W18-W29",
  "source": "Source: sample dataset v1, 2026-07-12",
  "columns": [
    "W18",
    "W19",
    "W20",
    "W21",
    "W22",
    "W23",
    "W24",
    "W25",
    "W26",
    "W27",
    "W28",
    "W29"
  ],
  "rows": [
    {
      "label": "Mon",
      "values": [
        9,
        10,
        11,
        10,
        12,
        11,
        12,
        12,
        14,
        11,
        13,
        14
      ]
    },
    {
      "label": "Tue",
      "values": [
        14,
        13,
        15,
        16,
        15,
        17,
        16,
        18,
        16,
        17,
        19,
        20
      ]
    },
    {
      "label": "Wed",
      "values": [
        18,
        19,
        18,
        20,
        21,
        20,
        22,
        22,
        25,
        21,
        24,
        26
      ]
    },
    {
      "label": "Thu",
      "values": [
        27,
        28,
        30,
        31,
        33,
        34,
        36,
        38,
        41,
        44,
        47,
        49
      ]
    },
    {
      "label": "Fri",
      "values": [
        12,
        13,
        12,
        14,
        14,
        15,
        15,
        16,
        15,
        18,
        17,
        18
      ]
    }
  ]
}