Add PHEP 3 to PyHC's Website

_data/pheps.yml

@@ -28,3 +28,17 @@
   Status: Final
   Title: PHEP Template
   Type: Informational
+- Author: Shawn Polson <pyhc-confidential@lasp.colorado.edu> <https://orcid.org/0000-0003-0619-5745>
+  Content-Type: text/markdown; charset="UTF-8"; variant="CommonMark"
+  Created: 06-Jun-2024
+  DOI: 10.5281/zenodo.17794207
+  Discussions-To: https://github.com/heliophysicsPy/standards/pull/29
+  Filename: phep-0003.md
+  PHEP: 3
+  Post-History: 06-Jun-2024, 11-Jun-2024, 02-Jul-2024, 17-Jul-2024, 23-Jul-2024, 05-Sep-2024,
+    09-Sep-2024, 28-Oct-2025, 02-Dec-2025
+  Resolution: https://doi.org/10.5281/zenodo.15080483, https://github.com/heliophysicsPy/standards/pull/29
+  Revision: 1
+  Status: Final
+  Title: PyHC Python & Upstream Package Support Policy
+  Type: Standards Track

_pages/docs/phep-3-support-schedule.md

@@ -0,0 +1,12 @@
+---
+layout: page
+title: PHEP 3 Support Schedule
+permalink: /docs/pheps/phep-3-support-schedule/
+exclude: true
+---
+
+TODO.
+
+Per PHEP 3's "How to Teach This" section:
+- The PyHC Tech Lead will maintain a new web page on the PyHC website detailing the support policy and include a graphical timeline of the schedule (similar to the Gantt chart above).
+ - Automated email reminders will be sent via the PyHC mailing list quarterly and near important drop/support dates to remind package maintainers of the schedule.

_pages/docs/pheps.md

@@ -29,3 +29,11 @@ PyHC Enhancement Proposals are developed via the <a href="https://github.com/hel
 </p>
 {% assign id = 2 %}
 {% include phep_table.html sorted_pheps=sorted_pheps table_id=id %}
+
+<br>
+
+<h3>Subpages</h3>
+<p>
+  These subpages provide additional content for accepted PHEPs.
+</p>
+ - [PHEP 3 Support Schedule](/docs/pheps/phep-3-support-schedule/)

_posts/2025-12-02-phep-3-announcement.markdown

@@ -0,0 +1,19 @@
+---
+layout: post
+title: "Announcing PHEP 3"
+author: sapols
+---
+
+<img src="/../img/page_images/phep3-gantt.jpg" alt="PHEP 3 Support Window" style="display: block; margin-left: auto; margin-right: auto; width: 60%">
+
+PyHC has formally adopted **[PHEP 3: PyHC Python & Upstream Package Support Policy](https://github.com/heliophysicsPy/standards/blob/main/pheps/phep-0003.md)**! This new PHEP establishes a unified, time-based approach to dependency support across the PyHC ecosystem, bringing our community into alignment with the broader Scientific Python ecosystem.
+
+PHEP 3 recommends that all PyHC packages adopt the following support policy, based on [SPEC 0](https://scientific-python.org/specs/spec-0000/):
+
+- **Support Python versions for 36 months** (3 years) after their initial release
+- **Support core Scientific Python packages for 24 months** (2 years) after their initial release
+- **Adopt new versions within 6 months** of their release
+
+This policy applies to Python itself and to the upstream [core Scientific Python packages](https://scientific-python.org/specs/core-projects/): NumPy, SciPy, Matplotlib, pandas, scikit-image, NetworkX, scikit-learn, xarray, IPython, and Zarr.
+
+To learn more, read **[the full PHEP 3 document](https://github.com/heliophysicsPy/standards/blob/main/pheps/phep-0003.md)**. We will also maintain a [PHEP 3 Support Schedule page](/docs/pheps/phep-3-support-schedule/) with a graphical timeline and quarterly reminders to help package maintainers stay on track. Questions or feedback? Join the discussion on [PyHC's mailing list or Slack](/contact)!