Building an "On This Day" Feature for My Jekyll Site

I’ve always been drawn to the little moments of rediscovery that my Day One journal creates with its “On This Day” feature. It’s delightful to stumble across a post you wrote years ago on the same date. So I decided to implement a similar feature on my Jekyll site, allowing me to revisit past posts from the same day in my history.

The Simple Solution

The implementation turned out to be elegantly straightforward. Jekyll’s Liquid templating system gives you everything you need to filter posts by date patterns. Here’s the core logic I landed on:

{% assign today = site.time | date: "%m-%d" %}
{% for post in site.posts %}
{% assign post_date = post.date | date: "%m-%d" %}
{% if post_date == today %}
{%- include PostListItem.html post=post dated=true -%}
{% endif %}
{% endfor %}

The magic happens in those date filters. I extract just the month and day (%m-%d) from both the current date and each post’s date, then match them up. Posts that share today’s month-day combination get displayed.

Breaking Down the Components

Date Extraction: site.time | date: "%m-%d" grabs today’s date in MM-DD format. Jekyll automatically provides site.time as the current build time.

Post Iteration: The loop runs through every post in site.posts, which Jekyll populates from all your _posts directories.

Pattern Matching: By comparing just the month-day portion, I catch posts from any year that happened on this date.

Presentation: I reuse my existing PostListItem.html include, but pass dated=true to show the full date (including year) since that context matters for “memory” posts.

The Page Structure

I created a simple page at /on-this-day.md with Jekyll’s Page layout:

---
layout: Page
title: On This Day
searchable: true
tags:
- index
- personal-blog
---

The page includes a brief explanation and links to my heatmap calendar (details on how that is built) for deeper exploration. It’s tagged as an index page so it appears in my site navigation.

What I Like About This Approach

Zero Dependencies: No plugins, no external services, just core Jekyll functionality.

Fast Performance: The date matching happens during site generation, not at runtime. The page loads instantly.

Cross-Category: Since I loop through site.posts, it catches everything - blog posts, notes, exercise logs, replies. The variety makes the feature more interesting.

Potential Enhancements

There are some obvious directions this could go:

• Date Range: Show posts from this week in history, not just this exact date
• Extract as Plugin: Create a reusable Jekyll plugin for this feature
• Sequences: Consider Sequences and display ones that started on this exact date

But honestly, the current implementation works perfectly for my needs. It’s one of those features where the simple solution is often the right solution.

The Broader Pattern

What I appreciate most is how this fits into Jekyll’s philosophy of doing complex things with simple tools. The same date filtering technique powers other chronological features - anniversary posts, seasonal collections, or historical timelines.

It’s also a good reminder that sometimes the best features are the ones that emerge naturally from your existing tools. I didn’t need to reach for anything fancy here. Jekyll’s built-in date handling and Liquid templating were more than sufficient to create something genuinely useful.

If you’re running a Jekyll site and want to add this kind of retrospective feature, give it a try. The code is minimal, the maintenance is zero, and the occasional rediscovery of old posts is surprisingly rewarding.