PHP compare dates returns true

I have the following date from a dates array:

  $expiryDate = date('d F Y', max($expiryDates));
  
  echo $expiryDate . ' < ' . date('d F Y'); // outputs: 01 January 2021 < 06 January 2020

I'm trying to compare if this date is less than todays date but its returning true?

 if ($expiryDate < date('d F Y') {
      // do something
 }

01 January 2021 is clearly greater than 06 January 2020 so why is it returning true

If the date formats for both your dates are different you can use, strtotime to compare both dates.

$d1 = "10-08-16"; 
$d2 = "2011-11-20"; 
  

$dn1 = strtotime($d1); 
$dn2 = strtotime($d2); 
  
 
if ($dn1 > $dn2) 
    echo "$dn1 is latest than $dn2"; 
else
    echo "$dn1 is older than $dn2"; 
  
?> 

You are comparing strings, thats the problem.
You can use DateTime class to do what you want.

$now = new DateTime();
$yesterday = new DateTime('yesterday');

# It will return 1 that is true
echo $now > $yesterday;

You can find more examples in https://www.php.net/manual/en/datetime.examples-arithmetic.php

you can use strtotime to compare the dates

 $expiryDate = "01 January 2021";
    
    if (strtotime($expiryDate) < strtotime(date('d F Y'))) {
    	echo "expiry date is less than current date";
     }else
    	echo "expiry date is greater than current date";

You have to use correct format for comparison and use below comparison format.

$expiryDate = date("Y-m-d H:i:s", max($expiryDates));

if ($expiryDate < date("Y-m-d H:i:s") {
      // do something
 }