Time Manipulation


This page is a cheat sheet for working with datetime objects in Home Assistant.

The code blocks below can be copied and pasted directly into the template editor in Home Assistant (your_HA_URL:8123/developer-tools/template) to see how the jinja syntax is evaluated. In the block below, only the content between the mustache braces {}, including the braces, are jinja.

Basic Date & Time:

1) {{ now() }} => 2024-07-02 11:24:17.517844-07:00
2) {{ utcnow() }} => 2024-07-02 18:24:17.517844+00:00
3) {{ today_at() }} => 2024-07-02 00:00:00-07:00
4) {{ as_timestamp( now() ) }} => 1719944760.209791
  1. Returns the current local datetime value (note “-07:00” at end).
  2. Returns current UTC datetime value (note “+00:00” at end).
  3. Returns today’s “Zero hour” (i.e. when the date & time turn at midnight) - useful in triggers & calculations.
  4. Returns the current local time and date in UNIX Time (in seconds) - useful when a time difference needs to be calculated.



  • BEWARE!!

    1) {{ now() }} => 2024-07-02 11:24:17.517844-07:00
2) {{states.sun.sun.last_changed}} => 2024-07-02 12:50:42.842225+00:00
3) {{ as_datetime(states.sun.sun.last_changed) | as_local }} => 2024-07-02 05:50:42.842225-07:00
BUT:
4) {{ as_timestamp(as_datetime(states.sun.sun.last_changed) | as_local) }} => 1719944760.209791
5) {{ as_timestamp(states.sun.sun.last_changed) }} => 1719944760.209791
    1. Local datetime value as per first example
    2. But this datetime value is actually in UTC (perhaps not what you want, unless you are actually in UTC)
    3. Use this instead to get the correct local datetime of when a device last changed (in this example, 5:50 was sunrise so the timestamp makes sense now)

    BUT: When doing time comparisons between two times, and a time difference needs to be determined, it is often easier to convert them to UNIX time and then subtract the two to find the difference. Here, 4 & 5 will convert to the same UNIX time as they both represent the SAME moment in time.



Date & Time Retrieval

Show month & day: {{ as_timestamp(states.sun.sun.last_changed) | timestamp_custom(' %B %d') | replace(" 0", "") }} => July 2
  OR month & day with an Ordinal label {{now().strftime('%B %-d') | ordinal}} => July 2nd
Show time of day: {{ as_timestamp(states.sun.sun.last_changed) | timestamp_custom(' %I:%M %p') | replace(" 0", "") }} => 5:50 AM
Show days of week, month, and time {{ as_timestamp(states.sun.sun.last_changed) | timestamp_custom('%A %B %-d, %-I:%M %p') }} => Tuesday July 2, 5:50 AM
Show hour & minute ("00:00") format: {{ now().strftime("%-H:%M") }} => 9:54
Show year only: {{now().strftime('%Y')}} => 2024
Time Now: {{as_timestamp(now())|timestamp_custom('%X')}} => 12:22:26
Date Now: {{as_timestamp(now())|timestamp_custom('%x')}} => 07/02/24
Tomorrow's date: {{ as_timestamp(now() + timedelta(days=1)) | timestamp_custom('%a %-d %b') }} => Wed 3 Jul
Compare time as True/False: {{now() | as_datetime > today_at("07:30")}} => True

Good Resources:



More Code Snippets

Countdown to month end (remaining days):

{% set this = now() %} 
{% set next = this.month + 1 if this.month + 1 <= 12 else 1 %} 
{% set last = this.replace(month=next, day=1) %} 
{{(last.date() - this.date()).days}}



Find the days in the month:

{% set start = now().replace(day=1) %}
{% set month = start.month + 1 if start.month < 12 else 1 %}
{% set year = start.year + 1 if start.month == 12 else start.year %}
{% set end = start.replace(year=year, month=month) %}
{{ (end-start).days }}



Create an sensor to calculate the hours of sunlight per day (note, this is in the legacy format):

- platform: template
  sensors:
    daylight_hours_today:
    friendly_name: 'Daylight hours today'
    value_template: >
      {% set sunrise = as_timestamp(state_attr('sun.sun','next_rising')) %}
      {% set sunset = as_timestamp(state_attr('sun.sun','next_setting')) %}
      {% set midnight = as_timestamp(state_attr('sun.sun','next_midnight')) %}
      {% if midnight < sunset %}
      {% set sunrise = (sunrise - 86328.5) %}
      {% set sunset = (sunset - 86471.5) %}
      {% endif %}
      {% if sunrise > sunset %}
      {% set sunrise = (sunrise - 86328.5) %}
      {% endif %}
      {{ (sunset - sunrise)|timestamp_custom('%H:%M',false) }}
      icon_template: mdi:weather-sunny



Example Dump (Unorganized)
- {{ as_timestamp(state_attr('automation.bwm_flur', 'last_triggered')) | timestamp_custom('%Y.%m.%dT%H:%M:%S') }}
- {{ state_attr('automation.bwm_flur', 'last_triggered') }}