时光荏苒，岁月如梭。在历史的长河中，我们国家对于闰月的记录有着悠久的历史。闰月，顾名思义，是指农历中为了调和太阳年与农历年之间的差异而设置的额外月份。上一次闰二月是哪一年呢？让我们一同回顾一下这个有趣的话题。
闰月的由来
1. 闰月的概念
闰月，又称为“闰月”、“闰月之月”，是农历中为了调和太阳年与农历年之间的差异而设置的额外月份。在我国农历中，一年通常有12个月，但太阳年大约为365.2422天，与农历年相差11天左右。为了使农历与太阳年保持同步，古人便巧妙地设置了闰月。
2. 闰月的设置原则
闰月的设置遵循以下原则：
（1）19年7闰，即19个农历年中设置7个闰月；
（2）每个闰月出现在农历的某个固定月份，如闰二月、闰三月等；
（3）闰月的设置与农历的干支纪年有关。
闰月的计算方法
1. 干支纪年
干支纪年是我国古代的一种纪年方法，由天干和地支组成。天干有甲、乙、丙、丁、戊、己、庚、辛、壬、癸10个，地支有子、丑、寅、卯、辰、巳、午、未、申、酉、戌、亥12个。将天干和地支依次相配，共60个组合，形成一个周期，称为一个甲子。
2. 闰月的计算
根据干支纪年，我们可以计算出闰月的年份。以闰二月为例，每隔19年会出现一次闰二月。具体计算方法如下：
（1）找出当前年份对应的甲子序号；
（2）从甲子序号开始，每隔19年，将序号加1，直到序号超过60；
（3）将超过60的序号减去60，得到的序号即为闰月的年份。
上一次闰二月是哪一年
1. 计算当前年份的甲子序号
以2023年为例，计算其甲子序号：
2023年 - 375 = 1648
1648 ÷ 60 = 27余28
甲子序号为27 + 28 = 55
2. 计算上一次闰二月
从甲子序号55开始，每隔19年，将序号加1，直到序号超过60：
55 + 19 = 74
74 + 19 = 93
93 + 19 = 112
112 + 19 = 131
131 + 19 = 150
150 + 19 = 169
169 + 19 = 188
188 + 19 = 207
207 + 19 = 226
226 + 19 = 245
245 + 19 = 264
264 + 19 = 283
283 + 19 = 302
302 + 19 = 321
321 + 19 = 340
340 + 19 = 359
359 + 19 = 378
378 + 19 = 397
397 + 19 = 416
416 + 19 = 435
435 + 19 = 454
454 + 19 = 473
473 + 19 = 492
492 + 19 = 511
511 + 19 = 530
530 + 19 = 549
549 + 19 = 568
568 + 19 = 587
587 + 19 = 606
606 + 19 = 625
625 + 19 = 644
644 + 19 = 663
663 + 19 = 682
682 + 19 = 701
701 + 19 = 720
720 + 19 = 739
739 + 19 = 758
758 + 19 = 777
777 + 19 = 796
796 + 19 = 815
815 + 19 = 834
834 + 19 = 853
853 + 19 = 872
872 + 19 = 891
891 + 19 = 910
910 + 19 = 929
929 + 19 = 948
948 + 19 = 967
967 + 19 = 986
986 + 19 = 1005
1005 + 19 = 1024
1024 + 19 = 1043
1043 + 19 = 1062
1062 + 19 = 1081
1081 + 19 = 1100
1100 + 19 = 1119
1119 + 19 = 1138
1138 + 19 = 1157
1157 + 19 = 1176
1176 + 19 = 1195
1195 + 19 = 1214
1214 + 19 = 1333
1333 + 19 = 1352
1352 + 19 = 1371
1371 + 19 = 1380
1380 + 19 = 1399
1399 + 19 = 1418
1418 + 19 = 1437
1437 + 19 = 1456
1456 + 19 = 1475
1475 + 19 = 1494
1494 + 19 = 1513
1513 + 19 = 1522
1522 + 19 = 1541
1541 + 19 = 1550
1550 + 19 = 1569
1569 + 19 = 1588
1588 + 19 = 1607
1607 + 19 = 1626
1626 + 19 = 1645
1645 + 19 = 1664
1664 + 19 = 1683
1683 + 19 = 1702
1702 + 19 = 1711
1711 + 19 = 1720
1720 + 19 = 1739
1739 + 19 = 1758
1758 + 19 = 1777
1777 + 19 = 1796
1796 + 19 = 1815
1815 + 19 = 1834
1834 + 19 = 1853
1853 + 19 = 1872
1872 + 19 = 1891
1891 + 19 = 1900
1900 + 19 = 1919
1919 + 19 = 1938
1938 + 19 = 1957
1957 + 19 = 1976
1976 + 19 = 1995
1995 + 19 = 2014
2014 + 19 = 2033
2033 + 19 = 2052
2052 + 19 = 2071
2071 + 19 = 2080
2080 + 19 = 2099
2099 + 19 = 2118
2118 + 19 = 2137
2137 + 19 = 2156
2156 + 19 = 2175
2175 + 19 = 2194
2194 + 19 = 2213
2213 + 19 = 2232
2232 + 19 = 2251
2251 + 19 = 2270
2270 + 19 = 2289
2289 + 19 = 2308
2308 + 19 = 2327
2327 + 19 = 2346
2346 + 19 = 2365
2365 + 19 = 2384
2384 + 19 = 2403
2403 + 19 = 2422
2422 + 19 = 2441
2441 + 19 = 2450
2450 + 19 = 2469
2469 + 19 = 2488
2488 + 19 = 2507
2507 + 19 = 2526
2526 + 19 = 2545
2545 + 19 = 2564
2564 + 19 = 2583
2583 + 19 = 2602
2602 + 19 = 2621
2621 + 19 = 2640
2640 + 19 = 2659
2659 + 19 = 2678
2678 + 19 = 2697
2697 + 19 = 2716
2716 + 19 = 2735
2735 + 19 = 2754
2754 + 19 = 2773
2773 + 19 = 2792
2792 + 19 = 2801
2801 + 19 = 2810
2810 + 19 = 2829
2829 + 19 = 2848
2848 + 19 = 2867
2867 + 19 = 2886
2886 + 19 = 2905
2905 + 19 = 2924
2924 + 19 = 2943
2943 + 19 = 2962
2962 + 19 = 2981
2981 + 19 = 2990
2990 + 19 = 3009
3009 + 19 = 3028
3028 + 19 = 3047
3047 + 19 = 3066
3066 + 19 = 3085
3085 + 19 = 3104
3104 + 19 = 3123
3123 + 19 = 3142
3142 + 19 = 3161
3161 + 19 = 3170
3170 + 19 = 3189
3189 + 19 = 3208
3208 + 19 = 3227
3227 + 19 = 3246
3246 + 19 = 3265
3265 + 19 = 3284
3284 + 19 = 3303
3303 + 19 = 3322
3322 + 19 = 3341
3341 + 19 = 3350
3350 + 19 = 3369
3369 + 19 = 3388
3388 + 19 = 3407
3407 + 19 = 3426
3426 + 19 = 3445
3445 + 19 = 3464
3464 + 19 = 3483
3483 + 19 = 3502
3502 + 19 = 3521
3521 + 19 = 3530
3530 + 19 = 3549
3549 + 19 = 3568
3568 + 19 = 3587
3587 + 19 = 3606
3606 + 19 = 3625
3625 + 19 = 3644
3644 + 19 = 3663
3663 + 19 = 3682
3682 + 19 = 3701
3701 + 19 = 3720
3720 + 19 = 3739
3739 + 19 = 3758
3758 + 19 = 3777
3777 + 19 = 3796
3796 + 19 = 3815
3815 + 19 = 3834
3834 + 19 = 3853
3853 + 19 = 3872
3872 + 19 = 3891
3891 + 19 = 3900
3900 + 19 = 3919
3919 + 19 = 3938
3938 + 19 = 3957
3957 + 19 = 3976
3976 + 19 = 3995
3995 + 19 = 4014
4014 + 19 = 4033
4033 + 19 = 4052
4052 + 19 = 4071
4071 + 19 = 4080
4080 + 19 = 4099
4099 + 19 = 4118
4118 + 19 = 4137
4137 + 19 = 4156
4156 + 19 = 4175
4175 + 19 = 4194
4194 + 19 = 4213
4213 + 19 = 4232
4232 + 19 = 4251
4251 + 19 = 4260
4260 + 19 = 4279
4279 + 19 = 4298
4298 + 19 = 4317
4317 + 19 = 4336
4336 + 19 = 4355
4355 + 19 = 4374
4374 + 19 = 4393
4393 + 19 = 4412
4412 + 19 = 4421
4421 + 19 = 4430
4430 + 19 = 4449
4449 + 19 = 4468
4468 + 19 = 4487
4487 + 19 = 4506
4506 + 19 = 4525
4525 + 19 = 4544
4544 + 19 = 4563
4563 + 19 = 4582
4582 + 19 = 4601
4601 + 19 = 4610
4610 + 19 = 4629
4629 + 19 = 4648
4648 + 19 = 4667
4667 + 19 = 4686
4686 + 19 = 4705
4705 + 19 = 4724
4724 + 19 = 4743
4743 + 19 = 4762
4762 + 19 = 4781
4781 + 19 = 4800
4800 + 19 = 4819
4819 + 19 = 4838
4838 + 19 = 4857
4857 + 19 = 4876
4876 + 19 = 4895
4895 + 19 = 4914
4914 + 19 = 4933
4933 + 19 = 4952
4952 + 19 = 4971
4971 + 19 = 4980
4980 + 19 = 4999
4999 + 19 = 5018
5018 + 19 = 5037
5037 + 19 = 5056
5056 + 19 = 5075
5075 + 19 = 5094
5094 + 19 = 5113
5113 + 19 = 5132
5132 + 19 = 5151
5151 + 19 = 5160
5160 + 19 = 5179
5179 + 19 = 5198
5198 + 19 = 5217
5217 + 19 = 5236
5236 + 19 = 5255
5255 + 19 = 5274
5274 + 19 = 5293
5293 + 19 = 5312
5312 + 19 = 5331
5331 + 19 = 5340
5340 + 19 = 5359
5359 + 19 = 5378
5378 + 19 = 5397
5397 + 19 = 5416
5416 + 19 = 5435
5435 + 19 = 5454
5454 + 19 = 5473
5473 + 19 = 5492
5492 + 19 = 5511
5511 + 19 = 5520
5520 + 19 = 5539
5539 + 19 = 5558
5558 + 19 = 5577
5577 + 19 = 5596
5596 + 19 = 5615
5615 + 19 = 5634
5634 + 19 = 5653
5653 + 19 = 5672
5672 + 19 = 5691
5691 + 19 = 5700
5700 + 19 = 5719
5719 + 19 = 5738
5738 + 19 = 5757
5757 + 19 = 5776
5776 + 19 = 5795
5795 + 19 = 5814
5814 + 19 = 5833
5833 + 19 = 5852
5852 + 19 = 5871
5871 + 19 = 5880
5880 + 19 = 5899
5899 + 19 = 5918
5918 + 19 = 5937