Since May 2016 Github does not provide anymore your current streak and your longest streak of contributions.
Read it here: https://github.com/blog/2173-more-contributions-on-your-profile
If you want it back, like it was, just install this extension

Install

• License: Mozilla Public License 2.0
• Weekly downloads: 0
• Average daily users: 44
• Rating: 0/5 of 0 ratings
• Created: 2016-05-31 08:12:14
• Last updated: 2021-06-30 12:25:55
• Homepage:
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/github-original-streak/
• API: @8c81e8d8-0795-4c81-be48-52db2291faa3