Magento – Invalid input datetime

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protected $timezone;

public function __construct(
\Magento\Framework\Stdlib\DateTime\TimezoneInterface $timezone,
......
)
{
    $this->timezone = $timezone;
}

$dateTimeZone = $this->timezone->date(new \DateTime($yourdate))->format('m/d/y H:i:s');

The timezone is right. The origin of the problem is the wrong timeFormat in the answer of Magento 2 - How to add the DateTime UI Component, We need change hh:mm:ss to HH:mm:ss in the UI Componet, otherwise 03:00:00 PMand 03:00:00 AM will became the same time, lack 12 hours and you can not save the time of PM in DB table.

Below is the original answer from Magento 2 - How to add the DateTime UI Component, we need change <item name="timeFormat" xsi:type="string">hh:mm:ss</item> to <item name="timeFormat" xsi:type="string">HH:mm:ss</item>.

<field name="start_date">
    <argument name="data" xsi:type="array">
        <item name="config" xsi:type="array">
            <item name="dataType" xsi:type="string">string</item>
            <item name="label" xsi:type="string" translate="true">Go Live Start Date</item>
            <item name="formElement" xsi:type="string">date</item>
            <item name="source" xsi:type="string">page</item>
            <item name="sortOrder" xsi:type="number">21</item>
            <item name="dataScope" xsi:type="string">start_date</item>
            <item name="validation" xsi:type="array">
                <item name="required-entry" xsi:type="boolean">true</item>
            </item>
            <item name="options" xsi:type="array">
                <item name="dateFormat" xsi:type="string">yyyy-MM-dd</item>
                <item name="timeFormat" xsi:type="string">hh:mm:ss</item>
                <item name="showsTime" xsi:type="boolean">true</item>
            </item>
        </item>
    </argument>
</field>