Hi Danish,

Unfortunately the widget has not setting to change the start of the weekday. If you want to do this you need to change the code of the widget (child theme recommend). If you want to do this I can provide you the steps for it, let me know.

Or you can add the opening hours as html block, but the highlight of the current day feature will not be available in html because this is a php function.

You can add the following code to a "Custom HTML" widget:

<div class="widget widget-opening-hours">
    <h4 class="widget-title"><span class="light">Working</span> Hours</h4>
    <div class="opening-hours">
        <ul>
            <li class="weekday">Sunday<span class="right label">CLOSED</span></li>
            <li class="weekday">Monday<span class="right">07:00 - 17:00</span></li>
            <li class="weekday">Tuesday<span class="right">07:00 - 17:00</span></li>
            <li class="weekday">Wednesday<span class="right">07:00 - 17:00</span></li>
            <li class="weekday">Thursday<span class="right">07:00 - 17:30</span></li>
            <li class="weekday">Friday<span class="right">07:00 - 17:00</span></li>
            <li class="weekday">Saturday<span class="right">09:00 - 15:00</span></li>
        </ul>
    </div>
</div>

You're welcome Dan!