First column:   year   month .   Number of months
Repeat day codes every columns.   Entry padding em.  

202520252025202520252025
JunJulAugSepOctNov
      
MoMo1Mo
Tu1Tu2Tu
We2We31We
Th3Th42Th
Fr41Fr53Fr
Sa52Sa641Sa
Su163Su752Su
      
Mo274Mo863Mo
Tu385Tu974Tu
We496We1085We
Th5107Th1196Th
Fr6118Fr12107Fr
Sa7129Sa13118Sa
Su81310Su14129Su
      
Mo91411Mo151310Mo
Tu101512Tu161411Tu
We111613We171512We
Th121714Th181613Th
Fr131815Fr191714Fr
Sa141916Sa201815Sa
Su152017Su211916Su
      
Mo162118Mo222017Mo
Tu172219Tu232118Tu
We182320We242219We
Th192421Th252320Th
Fr202522Fr262421Fr
Sa212623Sa272522Sa
Su222724Su282623Su
      
Mo232825Mo292724Mo
Tu242926Tu302825Tu
We253027We2926We
Th263128Th3027Th
Fr2729Fr3128Fr
Sa2830Sa29Sa
Su2931Su30Su
      
Mo30MoMo

36 rows

Notes on curious non-bug on my home machine:
with date_default_timezone_set('UTC') - be patient
without that declaration