Tropical Cyclone Wind Signals

Also known as: TCWS · Wind signals · Signal No. 1 to Signal No. 5 · Bagyong signal (colloquial Filipino usage) · Public Storm Warning Signal or PSWS (predecessor system before 2022) · Storm signal numbers

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Definition

Tropical Cyclone Wind Signals (TCWS) — in Filipino usage simply “signal numbers” or bagyong signal — are the numbered public wind warnings issued by PAGASA, the Philippine national meteorological service, for land areas expected to experience winds of at least 39 km/h from a tropical cyclone within at most 36 hours. The system comprises five signals, Signal No. 1 through Signal No. 5, each pairing a wind-speed band with a warning lead time — from 36 hours at Signal No. 1 down to 12 hours at Signals No. 4 and 5 — and a published catalogue of expected structural, utility, and agricultural damage. The current five-signal system has been in use since March 23, 2022, when PAGASA overhauled both the warning ladder and its tropical cyclone classifications. (PAGASA — Tropical Cyclone Wind Signal, PAGASA — About Tropical Cyclone)

The signals are the working language of every Philippine typhoon season: class suspensions, preemptive evacuations, and work cancellations are keyed to the number hoisted over a province, and a signal’s lead time is the clock households set preparations by. TCWS numbers are warnings keyed to expected winds over a specific place and time window, not an intensity scale for the storm itself — the essential difference from the American Saffir–Simpson categories, which grade a hurricane’s own strength wherever it is. (PAGASA — Tropical Cyclone Wind Signal, Wikipedia — Tropical cyclone warnings and watches, Saffir–Simpson scale — Wikipedia)

Identities

Source Type	Identity
Wikipedia	Tropical cyclone warnings and watches
Wikidata	Tropical cyclone warnings and watches (Q665469)
DBpedia	N/A
ProductOntology	N/A
Wiktionary	N/A
Library of Congress Subject Headings (LCSH)	N/A
MeSH	N/A
NCBI Taxonomy	N/A
AGROVOC	N/A
Google Scholar	tropical cyclone wind signal TCWS PAGASA public storm warning signal Philippines early warning lead time
ConceptNet	N/A
OpenCyc	N/A

Also Known As

TCWS
Wind signals
Signal No. 1 to Signal No. 5
Bagyong signal (colloquial Filipino usage)
Public Storm Warning Signal or PSWS (predecessor system before 2022)
Storm signal numbers

Examples and Analogies

A ladder of five rungs: each signal is a wind band plus a countdown — No. 1 (39–61 km/h, 36 hours), No. 2 (62–88 km/h, 24 hours), No. 3 (89–117 km/h, 18 hours), No. 4 (118–184 km/h, 12 hours), No. 5 (185 km/h or higher, 12 hours) — so a rising signal both raises the danger and shortens the preparation window. (PAGASA — Tropical Cyclone Wind Signal, PAGASA bagong — Tropical Cyclone Wind Signal)
A countdown that shrinks as the wind grows: the design logic is inverse proportion — the stronger the expected winds, the less lead time forecasters can safely promise, which is why Signals 4 and 5 share the shortest 12-hour window and demand action already completed. (PAGASA — Tropical Cyclone Wind Signal)
A warning, not a category: where Saffir–Simpson grades a storm’s own intensity (Category 1 through 5, from 119 km/h, using one-minute winds, for Atlantic and eastern-Pacific hurricanes), a TCWS number grades the threat to a named place within a time window — the same typhoon can hold Signal 5 over one province and Signal 1 over another simultaneously. (Saffir–Simpson scale — Wikipedia, Wikipedia — Tropical cyclone warnings and watches)
Verified data (signal ladder, in use since 23 March 2022):
Signal No. 1: 39–61 km/h (22–33 kt), lead time 36 hours; minimal to minor damage to risky structures, tilted banana plants, threatened rice crops
Signal No. 2: 62–88 km/h (34–47 kt), 24 hours; minor-to-moderate structural damage, projectile debris, local power outages
Signal No. 3: 89–117 km/h (48–63 kt), 18 hours; substantial damage to makeshift structures, widespread utility disruption
Signal No. 4: 118–184 km/h (64–99 kt), 12 hours; complete roof failure and wall collapse possible, near-total power and telecom loss
Signal No. 5: 185 km/h or higher (100+ kt), 12 hours; severe to catastrophic damage, prolonged utility loss (PAGASA — Tropical Cyclone Wind Signal, PAGASA bagong — Tropical Cyclone Wind Signal)

Usage Scenarios

1. Typhoon-Season Public Warning

PAGASA hoists signals over provinces, independent component cities, or highly urbanized cities — Metro Manila treated as a single unit — whenever a cyclone threatens the Philippine Area of Responsibility’s landmass, escalating, de-escalating, or lifting them with each bulletin; levels can be skipped in either direction when a storm intensifies or weakens quickly. (PAGASA — Tropical Cyclone Wind Signal)

2. Household and LGU Preparation

Local governments and households convert the hoisted number into a checklist keyed to the lead time: securing roofs and signage at Signal 1, pre-positioning relief at Signal 2, preemptive evacuation of weak structures by Signal 3, and full shelter-in-place or clearance of coastal zones at Signals 4 and 5 — the operational doctrine every NDRRMC-led drill rehearses. (PAGASA — Tropical Cyclone Wind Signal)

3. Reading International Coverage

Filipinos following foreign media must translate: a “Category 5 hurricane” or a JTWC super typhoon rating describes the storm’s peak intensity by one-minute winds, while the local Signal No. 5 describes 185 km/h-class winds arriving at a named province within 12 hours — related figures serving different purposes, which is why PAGASA’s own bulletins, issued every three, six, or twelve hours by threat level, remain the reference for action inside the country. (Saffir–Simpson scale — Wikipedia, PAGASA — Wikipedia)

4. Interpreting Historical Records

Storm accounts before 2022 use the old Public Storm Warning Signal numbering, which topped out at No. 4 for winds above 185 km/h — so Typhoon Haiyan’s record Signal No. 4 of 2013 corresponds to today’s Signal No. 5 band, a renumbering researchers must apply when comparing historical and modern warnings. (Typhoon Haiyan — Wikipedia, PAGASA — About Tropical Cyclone)

Strategies

Ratchet preparations with the number: treat each signal as a distinct action tier rather than a single alarm, the escalation logic the five damage catalogues are built to serve. (PAGASA — Tropical Cyclone Wind Signal)
Act on the first issuance: the published lead time applies to a signal’s first hoisting — by the time a signal is raised, the countdown has already started, so preparation lag compounds at every escalation. (Wikipedia — Tropical cyclone warnings and watches)
Treat the signals as wind-only: TCWS says nothing direct about storm surge or rainfall — the hazards that killed most of Haiyan’s victims — so coastal and flood-prone communities must run surge and rain warnings as separate tracks whatever the wind signal reads. (Typhoon Haiyan — Wikipedia, Saffir–Simpson scale — Wikipedia)
Expect skipped levels: because escalation can jump — No. 1 straight to No. 3, as PAGASA explicitly warns — communities should not assume a gradual climb and delay for intermediate numbers. (PAGASA — Tropical Cyclone Wind Signal)
Anchor on the official cadence: follow PAGASA’s own bulletins at their three-, six-, or twelve-hour rhythm rather than unofficial trackers, since the official signal is what suspensions and evacuations are legally keyed to. (PAGASA — Wikipedia)

Security and Safety Measures

Read each signal’s damage catalogue literally: the official impact expectations — from tilted banana plants at Signal 1 to destroyed industrial buildings and prolonged utility loss at Signal 5 — are the basis for judging whether a shelter is adequate to the number hoisted. (PAGASA — Tropical Cyclone Wind Signal)
Heed the 12-hour wall at the top: Signals 4 and 5 mean destructive to catastrophic winds within half a day, leaving no window for last-minute movement; evacuation and securing must be complete before the signal, not after. (PAGASA — Tropical Cyclone Wind Signal, PAGASA bagong — Tropical Cyclone Wind Signal)
Do not equate low signal with safety: Haiyan’s deadliest hazard was sea, not wind, and rainfall flooding can devastate under a mere Signal 2 — the standing reason surge-prone and riverine communities evacuate independently of the wind ladder. (Typhoon Haiyan — Wikipedia)
Correct for local exposure: PAGASA itself cautions that actual winds can run stronger offshore and on high ground than the general signal suggests, so exposed settlements should add a margin to the provincial number. (PAGASA — Tropical Cyclone Wind Signal)
Institutional continuity: the system is maintained by the national service descended from the 1865 Jesuit Observatorio Meteorológico de Manila — the Weather Bureau of 1901, reorganized as PAGASA on December 8, 1972 — whose bulletin infrastructure is the single authoritative channel for signal changes. (PAGASA — Wikipedia)

Historical Context

Numbered storm warnings in the Philippines long predate the current ladder: the warning service grew out of the Manila observatory founded in 1865 and the American-era Weather Bureau, and through the twentieth century the public storm warning system ran to four signals, with the old Signal No. 4 covering everything above 185 km/h — the level hoisted over Leyte and Samar when Typhoon Haiyan (Yolanda) struck in November 2013, killing more than 6,300 people and forcing a national reckoning with how technical warnings reach the public. (PAGASA — Wikipedia, Typhoon Haiyan — Wikipedia)

The present system dates to March 23, 2022, when PAGASA adopted the five-level Tropical Cyclone Wind Signal scheme together with a revised tropical cyclone classification — tropical depression up to 62 km/h, tropical storm 62–88, severe tropical storm up to 117, typhoon 118–184, and super typhoon 185 and above — aligning the warning ladder with the classification bands so that each signal’s threshold matches a named storm category. The new top tier was pressed into service in its first season: on September 25, 2022, Super Typhoon Karding (international name Noru) drew Signal No. 5 over the Polillo Islands and the extreme northern portion of Quezon before crossing Luzon. (PAGASA — About Tropical Cyclone, PAGASA — Tropical Cyclone Wind Signal, Typhoon Noru — Wikipedia)

Challenges and Controversies

The 2022 Renumbering

Adding Signal No. 5 and re-cutting the bands re-educated a public whose habits were built on the old four-level PSWS — the same number now meaning a different wind band, and Haiyan-era Signal 4 coverage now split across two levels — a transition cost PAGASA accepted for clearer escalation logic and international alignment. (Typhoon Haiyan — Wikipedia, PAGASA — About Tropical Cyclone)

Wind-Only Warnings After Haiyan

The system’s central limitation is that it measures wind: Haiyan’s storm surge killed thousands under a correctly forecast wind signal, the failure mode that also dogs the Saffir–Simpson scale abroad and that the Philippines answers with separate rainfall and surge guidance rather than a combined number. (Typhoon Haiyan — Wikipedia, Saffir–Simpson scale — Wikipedia)

Comparing Signals with Foreign Categories

Media and netizens routinely equate “Signal 5” with “Category 5,” but the two systems differ in what they grade (threat to a place versus intensity of a storm), in wind-averaging conventions across basins, and in lead-time logic — equivalences that are loose at best and, forecasters caution, dangerous when used to downgrade a local threat. (Saffir–Simpson scale — Wikipedia, Wikipedia — Tropical cyclone warnings and watches)

Granularity and Local Variation

Signals are hoisted at province or city level — Metro Manila as one unit — which flatters real differences across a megacity or a long province, and PAGASA’s own caveat that terrain and exposure can make local winds stronger than the signal keeps the precision debate alive after every near-miss. (PAGASA — Tropical Cyclone Wind Signal)