Weird php date strtotime issue

Question

I'm seeing a strange issue using the "date" function and "strtotime" in PHP.

echo date('m/d/Y h:i:s a', time())."<br>";       //returns 04/29/2021 12:26:30 pm
echo date('M Y', strtotime('-5 months'))."<br>"; //returns Nov 2020
echo date('M Y', strtotime('-4 months'))."<br>"; //returns Dec 2020
echo date('M Y', strtotime('-3 months'))."<br>"; //returns Jan 2021
echo date('M Y', strtotime('-2 months'))."<br>"; //returns Mar 2021
echo date('M Y', strtotime('-1 months'))."<br>"; //returns Mar 2021
echo date('M Y')."<br>";                         //returns Apr 2021

My server time is correct, as indicated by the first line, but why does strtotime('-2 months') and strtotime('-1 months') return the same value (Mar 2021) twice?

Thanks in advance

Any unit of time larger than a week does not have a consistent definition, and even then DST, leap years, and leap _seconds_ will throw wrenches into the mix. — Sammitch, Apr 29 '21 at 18:39
This is the same principle as https://stackoverflow.com/questions/49750127/strange-behaviour-of-php-strtotime-function — Nigel Ren, Apr 29 '21 at 19:25

Kinglish · Answer 1 · 2021-04-29T19:00:29.513

4

You're testing this function on April 29 echo date('M Y', strtotime('-2 months')). It will return Feb 29, 2021 - a date that doesn't exist, so it's defaulting to the last day of Feb (28) and adding 1 to get March 1.

... I had a solution here but it's a bit of a hack compared to your solution below, so I removed it in favor of yours

edited Apr 29 '21 at 19:00

answered Apr 29 '21 at 18:37

Kinglish

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Ah! I see. That makes so much sense. What's the best way around this? I need to be able to pull the names of the months for 6 months in arrears. – Bryce Matheson Apr 29 '21 at 18:44
@BryceMatheson - I gave one way in my edited answer. – Kinglish Apr 29 '21 at 18:51
What about this? Would this work as a replacement? `code` echo date("M Y", strtotime("-5 month", strtotime(date("F") . "1"))) . "
"; echo date("M Y", strtotime("-4 month", strtotime(date("F") . "1"))) . "
"; echo date("M Y", strtotime("-3 month", strtotime(date("F") . "1"))) . "
"; echo date("M Y", strtotime("-2 month", strtotime(date("F") . "1"))) . "
"; echo date("M Y", strtotime("-1 month", strtotime(date("F") . "1"))) . "
"; echo date("M Y", time()) . "
"; `code` – Bryce Matheson Apr 29 '21 at 18:56

score 0 · Answer 2 · answered Apr 29 '21 at 18:57

This resolved it for me:

    echo date("M Y", strtotime("-5 month", strtotime(date("F") . "1"))) . "<br>";
    echo date("M Y", strtotime("-4 month", strtotime(date("F") . "1"))) . "<br>";
    echo date("M Y", strtotime("-3 month", strtotime(date("F") . "1"))) . "<br>";
    echo date("M Y", strtotime("-2 month", strtotime(date("F") . "1"))) . "<br>";
    echo date("M Y", strtotime("-1 month", strtotime(date("F") . "1"))) . "<br>";
    echo date("M Y", time()) . "<br>";

Thank you for the help!

score 0 · Answer 3 · answered Apr 29 '21 at 19:40

its quite simple

echo date('m/d/Y h:i:s a', time())."<br>";     //returns 04/29/2021 12:26:30 pm
echo date('M Y', strtotime('first day of -5 months'))."<br>"; //returns Nov 2020
echo date('M Y', strtotime('first day of -4 months'))."<br>"; //returns Dec 2020
echo date('M Y', strtotime('first day of -3 months'))."<br>"; //returns Jan 2021
echo date('M Y', strtotime('first day of -2 months'))."<br>"; //returns Feb 2021
echo date('M Y', strtotime('first day of -1 months'))."<br>"; //returns Mar 2021
echo date('M Y')."<br>";

Weird php date strtotime issue

3 Answers3