---
title: "Monthly Forecast"
method: POST
path: "/bazi/monthly"
tags: ["BaZi (Four Pillars)"]
---

# Monthly Forecast

`POST /bazi/monthly`

Same Sheng-Ke + branch-clash analysis as yearly, but applied to a specific calendar month. Month branch resolved via mid-month jieqi.

## Request body

- BaziMonthlyInput
  - `natalDate` string, required
  - `natalTime` string
  - `natalTzOffset` number
  - `targetYear` integer, required
  - `targetMonth` integer, required

## Response `200`

Successful calculation

- object
  - `ok` boolean
  - `data` object
    - `natalDayMaster` object, nullable
    - `targetPillar` object, nullable
      - `pillar` string, nullable
    - `elementFlow` object, nullable
    - `branchInteractions` object, nullable
      - `clashes` unknown[], nullable
        - unknown

## Other responses

- `400` — Validation error
- `401` — Missing or invalid API key

---

[API](https://skmtc.net/astroway/apis/astroway-calculation-api.md) · [All operations](https://skmtc.net/astroway/apis/astroway-calculation-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/astroway/astroway-calculation-api/revisions/529d7d36d7d6/schema)