Lipantitlan State Historic Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lipantitlan State Historic Site clear sky chart from 2005-11-05 to 2017-09-22.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
54%
15283
24%
47034
18%
15239
59%
15239
32%
27641

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
38%
897
21%
2327
10%
895
44%
895
29%
1558
January16th to endNight
40%
849
24%
2385
12%
849
48%
849
31%
1500
February1st to 15thNight
39%
704
26%
2112
13%
700
49%
700
29%
1288
February16th to endNight
29%
617
24%
1879
9%
617
42%
617
30%
1114
March1st to 15thNight
36%
540
26%
1980
15%
540
50%
540
24%
1178
March16th to endNight
36%
576
22%
2112
15%
576
48%
576
26%
1216
April1st to 15thNight
33%
539
19%
1977
10%
539
46%
539
25%
1163
April16th to endNight
31%
540
21%
1858
14%
540
44%
540
22%
1169
May1st to 15thNight
38%
539
21%
1620
14%
539
47%
539
29%
1011
May16th to endNight
49%
563
23%
1684
19%
561
58%
561
31%
1040
June1st to 15thNight
76%
540
19%
1620
22%
540
78%
540
45%
851
June16th to endNight
71%
540
18%
1620
21%
540
73%
540
37%
934
July1st to 15thNight
80%
510
19%
1530
21%
510
81%
510
39%
856
July16th to endNight
86%
564
22%
1594
25%
531
88%
531
48%
827
August1st to 15thNight
91%
539
28%
1709
33%
536
91%
536
57%
761
August16th to endNight
80%
573
18%
2012
21%
573
81%
573
32%
1113
September1st to 15thNight
77%
540
19%
1980
23%
540
77%
540
29%
1119
September16th to endNight
72%
513
23%
1891
26%
513
73%
513
28%
1087
October1st to 15thNight
78%
498
34%
1818
34%
498
79%
498
42%
861
October16th to endNight
64%
704
34%
2112
26%
704
67%
704
46%
1091
November1st to 15thNight
57%
700
26%
2100
19%
700
60%
700
34%
1233
November16th to endNight
53%
838
29%
2278
17%
838
59%
838
38%
1346
December1st to 15thNight
43%
900
24%
2340
15%
900
47%
900
26%
1615
December16th to endNight
38%
960
21%
2496
12%
960
42%
960
27%
1710

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
11%5%25%5%35%5%5%8%41%
47842
Night
11%42432345%8%49%
47230
TransparencyDay
39%6%12%19%15%7%
47542
Night
32%6%14%22%15%9%
47035
SeeingDay
10%319%33%25%7%
5220
Night
13%322%37%21%1
15287

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
22%6%25%422345%38%
1611
16th to endDay
15%6%3432335%6%45%
1851
February1st to 15thDay
17%6%34423346%44%
1750
16th to endDay
17%6%34313245%46%
1593
March1st to 15thDay
21%6%23423447%38%
1980
16th to endDay
12%5%35%5%24447%44%
2110
April1st to 15thDay
12%5%2443446%7%44%
1971
16th to endDay
14%7%24424447%42%
2096
May1st to 15thDay
9%6%36%5%35%5%6%8%39%
2331
16th to endDay
7%5%25%5%46%7%6%9%38%
2430
June1st to 15thDay
3414446%5%7%11%46%
2340
16th to endDay
6%437%7%48%5%8%9%34%
2340
July1st to 15thDay
7%5%36%5%47%6%6%9%36%
2340
16th to endDay
5%4246%47%6%6%10%41%
2466
August1st to 15thDay
21135%346%7%10%51%
2238
16th to endDay
6%427%7%37%7%7%10%35%
2188
September1st to 15thDay
9%6%37%7%5%6%7%7%8%30%
1980
16th to endDay
9%5%26%7%36%5%6%9%37%
1881
October1st to 15thDay
7%3245%345%6%8%49%
1800
16th to endDay
6%224324446%58%
1760
November1st to 15thDay
10%6%36%6%35%447%41%
1758
16th to endDay
13%5%25%422445%47%
1680
December1st to 15thDay
21%7%45%423345%37%
1620
16th to endDay
17%7%27%434347%38%
1728
January1st to 15thNight
21%6%23322335%45%
2327
16th to endNight
17%423423345%47%
2385
February1st to 15thNight
15%5%24323445%47%
2102
16th to endNight
14%6%23313346%50%
1879
March1st to 15thNight
17%6%24323337%44%
1980
16th to endNight
13%6%24423337%48%
2112
April1st to 15thNight
12%425%424448%43%
1977
16th to endNight
16%6%3443345%7%39%
1858
May1st to 15thNight
10%5%235%35%5%6%10%40%
1619
16th to endNight
7%5%245%35%5%7%12%41%
1683
June1st to 15thNight
3233245%7%10%55%
1620
16th to endNight
43233245%7%12%48%
1620
July1st to 15thNight
432332437%12%51%
1620
16th to endNight
31123145%7%12%56%
1702
August1st to 15thNight
1112133410%68%
1719
16th to endNight
44144245%6%10%52%
2012
September1st to 15thNight
7%325%43347%10%47%
1980
16th to endNight
8%5%25%42445%9%46%
1891
October1st to 15thNight
5%21231335%6%63%
1818
16th to endNight
6%31331323465%
2112
November1st to 15thNight
10%424423447%51%
2100
16th to endNight
11%413323346%55%
2278
December1st to 15thNight
21%5%35%32335%5%41%
2340
16th to endNight
18%8%25%323336%41%
2496

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
48%36%13%16%11%
1612
16th to endDay
40%38%16%17%12%
1851
February1st to 15thDay
41%37%13%18%15%
1751
16th to endDay
41%37%17%19%10%
1593
March1st to 15thDay
45%48%13%17%10%
1980
16th to endDay
39%5%10%16%15%12%
2112
April1st to 15thDay
36%5%10%17%18%10%
1971
16th to endDay
41%49%20%14%10%
2096
May1st to 15thDay
40%6%13%18%13%8%
2331
16th to endDay
38%7%11%20%17%3
2434
June1st to 15thDay
29%6%13%24%20%4
2340
16th to endDay
42%8%13%23%11%
2340
July1st to 15thDay
39%8%16%23%11%
2201
16th to endDay
34%8%22%30%4
2311
August1st to 15thDay
24%7%21%36%9%
2224
16th to endDay
39%11%18%22%5%1
2188
September1st to 15thDay
47%10%14%14%11%2
1980
16th to endDay
40%9%12%15%16%5%
1881
October1st to 15thDay
32%5%10%20%22%8%
1800
16th to endDay
25%49%18%25%15%
1760
November1st to 15thDay
41%5%9%15%17%10%
1758
16th to endDay
38%48%13%18%17%
1680
December1st to 15thDay
49%5%7%14%14%9%
1620
16th to endDay
46%37%16%15%9%
1728
January1st to 15thNight
43%37%14%16%15%
2327
16th to endNight
38%38%17%17%13%
2385
February1st to 15thNight
37%49%14%16%17%
2112
16th to endNight
36%48%20%19%11%
1879
March1st to 15thNight
39%49%15%17%12%
1980
16th to endNight
37%312%16%18%11%
2112
April1st to 15thNight
38%413%16%15%10%
1977
16th to endNight
42%5%9%17%13%10%
1858
May1st to 15thNight
36%7%15%19%12%9%
1620
16th to endNight
33%9%15%24%15%2
1685
June1st to 15thNight
20%7%18%28%21%2
1620
16th to endNight
26%9%19%30%13%
1620
July1st to 15thNight
23%10%23%34%7%
1530
16th to endNight
17%9%34%32%6%
1594
August1st to 15thNight
12%6%27%46%6%
1709
16th to endNight
25%11%27%27%6%
2012
September1st to 15thNight
30%8%21%25%11%2
1980
16th to endNight
33%7%14%23%15%5%
1891
October1st to 15thNight
20%6%13%28%21%10%
1818
16th to endNight
23%36%20%28%16%
2112
November1st to 15thNight
31%6%15%19%17%9%
2100
16th to endNight
30%5%10%18%16%19%
2278
December1st to 15thNight
44%5%8%16%15%9%
2340
16th to endNight
44%36%16%16%11%
2496

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
22%331%30%12%1
90
16th to endDay
15%6%44%14%17%1
96
February1st to 15thDay
8%6%34%28%14%6%
90
16th to endDay
12%9%37%30%8%1
81
March1st to 15thDay
32%328%20%15%
90
16th to endDay
14%6%32%37%9%
96
April1st to 15thDay
8%6%40%30%13%1
90
16th to endDay
16%9%34%27%10%
206
May1st to 15thDay
12%7%44%26%9%
468
16th to endDay
12%5%33%31%15%1
517
June1st to 15thDay
6%8%46%31%6%
495
16th to endDay
8%11%38%30%10%
495
July1st to 15thDay
5%18%40%36%8%
475
16th to endDay
6%6%36%40%10%
515
August1st to 15thDay
3440%34%17%
393
16th to endDay
9%10%40%24%14%
228
September1st to 15thDay
11%5%21%47%13%
135
16th to endDay
2318%41%33%
108
October1st to 15thDay
21223%45%25%
90
16th to endDay
16%111%35%29%6%
96
November1st to 15thDay
24%421%25%21%3
90
16th to endDay
26%5%23%23%14%6%
90
December1st to 15thDay
33%218%21%15%8%
90
16th to endDay
23%10%36%20%6%2
96
January1st to 15thNight
23%6%26%32%11%
900
16th to endNight
18%5%29%37%8%
849
February1st to 15thNight
18%9%27%35%7%
704
16th to endNight
17%8%40%28%5%
617
March1st to 15thNight
20%5%32%35%6%
540
16th to endNight
14%6%38%35%5%
576
April1st to 15thNight
15%343%30%6%
539
16th to endNight
18%5%40%27%7%
540
May1st to 15thNight
12%441%37%4
540
16th to endNight
10%131%41%14%
563
June1st to 15thNight
412%55%25%1
540
16th to endNight
5%14%48%28%2
540
July1st to 15thNight
5%7%50%35%1
510
16th to endNight
21345%43%3
564
August1st to 15thNight
2245%45%4
539
16th to endNight
6%334%49%5%
573
September1st to 15thNight
7%230%50%8%
540
16th to endNight
10%432%43%8%
513
October1st to 15thNight
6%8%35%44%3
498
16th to endNight
7%219%41%27%1
704
November1st to 15thNight
12%220%38%23%2
700
16th to endNight
13%424%34%20%2
838
December1st to 15thNight
23%421%36%12%1
900
16th to endNight
21%6%27%32%11%
960
Page generated at 2017-09-23 05:43:39. Version ac04

Copyright 2017 A. Danko


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