Five Seasons Calendar is a proposed Standard Year by Stavros Daliakopoulos, Greece.
The proposal consists of four large periods of 84 days and one small period of 28 days, i.e. 12 weeks and 4 weeks, respectively.
The seven-day week cycle is preserved but there are no more months.
First Period
Mon
Tue
Wed
Thu
Fri
Sat
Sun
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
Second period
Mon
Tue
Wed
Thu
Fri
Sat
Sun
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
Third period
Mon
Tue
Wed
Thu
Fri
Sat
Sun
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Fourth period
Mon
Tue
Wed
Thu
Fri
Sat
Sun
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
Fifth period
Mon
Tue
Wed
Thu
Fri
Sat
Sun
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84: Double or triple Sunday
To complete the 365-day cycle, the last Sunday of the year will be a "double" Sunday (DS), meaning it will have 48 hours instead of 24, so that the seven-day week is preserved.
The same principle will apply for the leap years so we have a "triple" Sunday (TS) every 4 years that has 72 hours instead of 24.
Advantages[]
No months to memorize
No 13 months as other proposals
The first weekday of the week is Monday as per ISO 8601
No Friday the 13th days (only five 13s in the whole calendar)
Each large period has 12 weeks
One small period has 4 weeks
Symmetrical (half year is 2 large and 1/2 small periods, or 182 days), so statistical comparisons are more accurate
Quarterly statistics are also easier (91 days for each quarter although they intercept periods)
Every day falls on the same weekday in each period (e.g. the 9th always falls on a Tuesday)
Each large period can be divided by 2, 3, 4 and 6. The small period can be divided by 2 and 4.
The calendar is the same every year (perennial), unlike the annual Gregorian calendar, which differs from year to year
Scheduling is easier for institutions and industries with extended production cycles.
Movable holidays would be able to have a fixed date while keeping their traditional weekday.
The periods could be given historical names.
Disadvantages[]
Birthdays, significant anniversaries, and other holidays would need to be recalculated as a result of a calendar reform, and would always be on the same day of the week
Large day count in periods.
Does not assign unique dates to the 364th, 365th (and 366th) days of a year.