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By Lashary Engineering Team • October 20, 2026 • Verified for Wrangler v4.151+

Cloudflare Workers Cron Triggers provide edge scheduled execution without managing dedicated cron daemons. However, because Cloudflare's distributed edge infrastructure evaluates all cron syntax strictly against Coordinated Universal Time (UTC), developers configuring tasks from local timezones frequently encounter off-by-hours bugs.

1. The UTC Conversion Mathematical Rule

To calculate the UTC hour $H_{UTC}$ from your local hour $H_{local}$ with an offset $O$ (e.g., $O = +5$ for Pakistan Standard Time):

For instance, if you want your scheduled Worker to execute daily at 09:00 AM PKT:
$H_{UTC} = (9 - 5) = 4$. Therefore, your cron expression is 0 4 * * *.

2. Configuring in modern wrangler.jsonc

In modern Wrangler projects, cron triggers are defined inside the triggers block of wrangler.jsonc:

{
  "name": "edge-scheduled-job",
  "main": "src/worker.js",
  "compatibility_date": "2026-10-01",
  "triggers": {
    "crons": [
      "0 4 * * *"  // Runs daily at 09:00 AM PKT (04:00 UTC)
    ]
  }
}

3. Testing Locally via Wrangler CLI

You do not need to wait for the actual scheduled time to verify your handler. Trigger your scheduled event directly in local development:

npx wrangler dev --test-scheduled
# In another terminal:
curl "http://localhost:8787/__scheduled?cron=0+4+*+*+*"