---
title: "Subtropical Westerly Jet Stream Explained | Model Diplomat"
description: "The subtropical westerly jet stream is a high-altitude wind band near 30°N that governs the onset and retreat of the Indian monsoon — a core UPSC GS1 topic."
url: "https://modeldiplomat.com/learn/glossary/subtropical-westerly-jet-stream"
---

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Model Diplomat Research Team · Last reviewed June 22, 2026

TL;DR

- The subtropical westerly jet stream is a fast, narrow band of high-altitude westerly winds that flows around both hemispheres near 30 degrees latitude.
- How does the subtropical westerly jet stream affect the Indian monsoon?
- What is the difference between the subtropical jet and the polar-front jet?
- Why is the subtropical westerly jet stronger in winter?
- What are western disturbances and how do they relate to the jet?

[Civil Service & Diplomatic Exams](https://modeldiplomat.com/learn/civil-services/glossary)Updated June 22, 2026

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In late May 2023 the India Meteorological Department tracked the northward retreat of the subtropical westerly jet across the Himalayas as a precursor to the southwest monsoon's onset over Kerala.

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