mikeage

KosherJava

This plugin allows WordPress to easily show Hebrew dates instead of (or in addition to) the standard Gregorian dates. No theme changes are required.
This plugin is based on the Hebrew Date plugin from KosherJava. All bugs are mine, though.
This plugin is slightly similar to https://wordpress.org/extend/plugins/wordpress-hebrew-date/, but much more robust. It’s also older, although not on wordpress.org
<h3>Known Issues</h3>
<ul>
<li>The sunset routine cannot take into account DST, since the wordpress offset is GMT +/-, not a timezone (not to mention the computational nightmare that is the Israeli timezone).</li>
</ul>

Hebrew Dates

This plugin allows WordPress to easily show Hebrew dates instead of (or in addition to) the standard Gregorian dates. No theme changes are required.

calj

Use the popular CalJ API to display the begin and end times of Shabbat as well as the name of the week’s Parasha on your blog, 
with the help of a simple shortcode

CalJ

Display the Shabbat times (zmanim) for the city of your choice.

Hebrew Dates vs CalJ