Run Yearly on Dec 31st at Midnight

cron expression Standard

$ 29 0 31 12 *

→

Once a year, on December 31st at midnight

Minute

Hour

Day of Month

Month

Day of Week

* In a Nutshell

The cron expression 29 0 31 12 * runs Once a year, on December 31st at midnight. This cadence is crucial for tasks that must run precisely once per year, such as year-end financial closing, generating annual reports, or performing critical system maintenance that is only feasible outside of active business periods. Executing on a specific date ensures all yearly data is finalized and processed correctly, preventing data staleness and ensuring compliance with reporting deadlines.

* When to use this

Use 29 0 31 12 * when a recurring task needs to run Once a year, on December 31st at midnight. This schedule is commonly associated with financial processing and monthly schedules and report generation workloads. It uses Standard (5-Field POSIX) syntax, supported by Unix cron daemons, cloud schedulers such as AWS EventBridge, and container orchestration platforms such as Kubernetes CronJob.

CronBase parses 29 0 31 12 * using a dialect-aware rules engine that identifies the Standard (5-Field POSIX) format, validates field structure against the Standard (5-Field POSIX) specification, and produces the translation above. Next run times are calculated by forward-scanning from the current UTC clock. Learn how CronBase works.

Platform Implementations

Bash

Prerequisites

Unix/Linux host with a cron daemon running (vixie-cron, cronie, or systemd-cron). The script at /usr/local/bin/run-task.sh must exist and be executable (chmod +x).

Configuration

Run crontab -e to open the crontab editor. Cron reads the server's local timezone; prefix with CRON_TZ=UTC before the expression to pin to UTC. Always redirect output with >> /var/log/cron-tasks.log 2>&1 to capture both stdout and stderr.

Gotchas

Cron jobs inherit a minimal PATH — use full binary paths or set PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin at the top of the crontab. For sub-hourly schedules, add flock -n /tmp/run-task.lock before the command to skip overlapping runs if the previous execution is still running.

bash

# Add to crontab with: crontab -e
29 0 31 12 * /usr/local/bin/run-task.sh >> /var/log/cron-tasks.log 2>&1

Last verified: April 17, 2026

Nodejs

Prerequisites

Node.js 18+ with node-cron installed (npm install node-cron). Add "type": "module" to package.json to use the import syntax shown above.

Configuration

Pass { timezone: 'UTC' } as the third argument to cron.schedule(). Without this option the schedule uses the Node.js process timezone, which shifts during DST transitions when servers are not pinned to UTC.

Gotchas

node-cron uses standard 5-field cron syntax — not Quartz 6-field. If your job runs longer than the schedule interval the next trigger fires while the previous is still executing. Use a boolean guard or a queue to skip concurrent runs rather than relying on the scheduler to enforce it.

nodejs

import cron from 'node-cron';

cron.schedule('29 0 31 12 *', async () => {
  console.log('[cron] running at', new Date().toISOString());
  // your task logic here
}, { timezone: 'UTC' });

Last verified: April 17, 2026

Python

Prerequisites

Python 3.8+ with apscheduler installed (pip install apscheduler). For Python 3.12+ use apscheduler>=3.10.

Configuration

CronTrigger.from_crontab() accepts a standard 5-field cron string. Always pass timezone='UTC' to both the BlockingScheduler constructor and the trigger to ensure consistent scheduling regardless of the server's locale.

Gotchas

BlockingScheduler.start() blocks the calling thread indefinitely. For a web application, use BackgroundScheduler instead and call scheduler.start() at application startup. APScheduler logs missed fires if the process is stopped and restarted — configure misfire_grace_time (in seconds) to control how late a missed job is allowed to run.

python

from apscheduler.schedulers.blocking import BlockingScheduler
from apscheduler.triggers.cron import CronTrigger

scheduler = BlockingScheduler(timezone='UTC')

@scheduler.scheduled_job(
    CronTrigger.from_crontab('29 0 31 12 *', timezone='UTC')
)
def run_task() -> None:
    print('task running')
    # your task logic here

scheduler.start()

Last verified: April 17, 2026

Golang

Prerequisites

Go 1.18+ and github.com/robfig/cron/v3 (go get github.com/robfig/cron/v3).

Configuration

Always create the scheduler with cron.New(cron.WithLocation(time.UTC)). Without WithLocation, the library defaults to the server's local timezone. Call c.Start() to begin the scheduler, then block with select {} to keep the process alive.

Gotchas

robfig/cron v3 uses standard 5-field cron expressions by default. To add second-level precision (6 fields), pass cron.WithSeconds() to cron.New() — but this changes field positions, so never mix syntaxes in the same scheduler. Always check the error returned by c.AddFunc() — a malformed expression is silently ignored without it.

golang

package main

import (
	"fmt"
	"time"

	"github.com/robfig/cron/v3"
)

func main() {
	c := cron.New(cron.WithLocation(time.UTC))
	_, err := c.AddFunc("29 0 31 12 *", func() {
		fmt.Println("task running at", time.Now().UTC())
		// your task logic here
	})
	if err != nil {
		panic(err)
	}
	c.Start()
	defer c.Stop()
	select {}
}

Last verified: April 17, 2026

Java

Prerequisites

Spring Boot 2.7+ (or Spring Framework 5.3+) with spring-context on the classpath. Annotate your @SpringBootApplication class with @EnableScheduling — without it, @Scheduled methods are silently ignored.

Configuration

Spring @Scheduled uses a 6-field Quartz-style expression: [sec] [min] [hr] [dom] [mon] [dow]. The expression 0 29 0 31 12 ? is derived from 29 0 31 12 * — a leading 0 is prepended for the seconds field, and ? replaces the unconstrained day field.

Gotchas

Standard Unix cron has 5 fields; Spring requires 6. Pasting a 5-field expression directly into @Scheduled shifts every field by one and the job misfires silently. Use ? for either dom or dow — Quartz does not allow both to be *.

java

import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

@Component
public class ScheduledTask {

    @Scheduled(cron = "0 29 0 31 12 ?")
    public void runTask() {
        System.out.println("task running at: " + java.time.Instant.now());
        // your task logic here
    }
}

Last verified: April 17, 2026

Kubernetes

Prerequisites

Kubernetes 1.21+ (CronJob API is GA). kubectl configured with cluster access. Container image must be pullable from within the cluster.

Configuration

Apply with kubectl apply -f cronjob.yaml. Check status with kubectl get cronjobs and inspect run history with kubectl get jobs. concurrencyPolicy: Allow is set because this schedule fires infrequently — parallel runs are acceptable.

Gotchas

Without startingDeadlineSeconds, a missed job (e.g., due to cluster downtime) triggers as soon as the controller recovers. Kubernetes 1.25+ supports timeZone: UTC in the spec to avoid timezone ambiguity. Keep successfulJobsHistoryLimit and failedJobsHistoryLimit low to avoid accumulating stale Job objects in the cluster.

kubernetes

apiVersion: batch/v1
kind: CronJob
metadata:
  name: scheduled-task
spec:
  schedule: "29 0 31 12 *"
  concurrencyPolicy: Allow
  jobTemplate:
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          containers:
          - name: task
            image: alpine:3.19
            command: ["/bin/sh", "-c", "echo 'task running'"]

Last verified: April 17, 2026

AWS EventBridge Equivalent

Standard cron expressions often need conversion for AWS EventBridge schedules.

EventBridge Rule

cron(29 0 31 12 ? *)

Frequently Asked Questions

What does the `29 0 31 12 *` cron expression specifically do?

This cron expression is configured to trigger a task exactly once per year, specifically at midnight on December 31st. It is designed for annual operational routines or data processing that needs to occur at the year's end.

How does this schedule handle time zones and daylight saving time changes?

Cron schedules operate based on the server's configured time zone. Any adjustments for daylight saving time or year-end time zone changes are automatically handled by the system's clock. Ensure your server's time zone is set correctly for predictable execution.

How can I verify that my annual task is running as scheduled?

To verify, check your system's logs for the execution of the intended task shortly after midnight on December 31st. You can also implement a simple notification or log entry within the task itself to confirm its successful run.

What potential issues should I be aware of with this annual schedule?

The primary concern is ensuring the task completes before the new year begins. If the task takes a very long time, it might interfere with other processes starting at the beginning of the year. Also, ensure your system clock is accurate for the specific date and time.

What is a common variation for this type of annual schedule?

A common variation might involve scheduling a task for January 1st instead of December 31st to capture the full previous year's data before processing. Another variation could be to run it at a different time of day if midnight is a critical period for other operations.