South Nation Space Station
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the South Nation Space Station clear sky chart from 2005-11-05 to 2017-09-23.

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
34%
14661
13%
46915
9%
14629
40%
14629
17%
33671

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
19%
720
7%
2506
4%
716
23%
716
8%
2021
January16th to endNight
25%
768
10%
2670
7%
768
31%
768
12%
2014
February1st to 15thNight
23%
704
10%
2287
5%
701
30%
701
12%
1767
February16th to endNight
27%
631
14%
1931
8%
631
35%
631
15%
1446
March1st to 15thNight
24%
720
13%
2127
8%
720
31%
720
15%
1606
March16th to endNight
33%
768
21%
2016
10%
768
41%
768
24%
1407
April1st to 15thNight
30%
718
15%
1796
6%
718
34%
718
22%
1321
April16th to endNight
31%
645
17%
1725
8%
645
38%
645
23%
1221
May1st to 15thNight
35%
360
17%
1440
17%
360
43%
360
16%
962
May16th to endNight
39%
375
13%
1497
12%
374
48%
374
18%
972
June1st to 15thNight
39%
360
9%
1440
9%
360
46%
360
15%
1002
June16th to endNight
46%
360
9%
1440
13%
360
50%
360
18%
917
July1st to 15thNight
60%
340
13%
1360
20%
340
64%
340
26%
774
July16th to endNight
60%
376
13%
1418
18%
354
63%
354
24%
827
August1st to 15thNight
57%
407
14%
1478
15%
405
61%
405
22%
939
August16th to endNight
57%
728
19%
1874
11%
728
60%
728
35%
1191
September1st to 15thNight
51%
720
15%
1800
8%
720
53%
720
28%
1257
September16th to endNight
53%
689
22%
1870
15%
689
57%
689
32%
1199
October1st to 15thNight
36%
660
18%
1980
12%
660
44%
660
21%
1382
October16th to endNight
30%
704
10%
2222
7%
704
36%
704
14%
1689
November1st to 15thNight
31%
700
17%
2310
13%
700
39%
700
17%
1649
November16th to endNight
23%
720
11%
2520
7%
720
28%
720
10%
1935
December1st to 15thNight
19%
720
8%
2520
4%
720
24%
720
9%
2008
December16th to endNight
15%
768
10%
2688
4%
768
22%
768
9%
2165

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
18%8%36%5%3445%6%32%
48005
Night
18%9%36%5%34445%33%
47084
Cloud CoverDay
18%8%36%5%3445%6%32%
48014
Night
18%9%36%5%34445%32%
47090
TransparencyDay
51%6%11%19%9%1
47692
Night
52%6%10%19%9%1
46915
SeeingDay
22%8%25%24%13%4
5529
Night
23%6%27%29%11%
14661

By Month

Percentage Cloud Cover NE (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
23%13%6%9%5%3433421%
1432
16th to endDay
14%15%5%9%5%35%45%425%
1554
February1st to 15thDay
13%14%5%11%7%35%436%24%
1575
16th to endDay
18%12%5%9%6%3434426%
1542
March1st to 15thDay
17%11%48%7%45%5%4427%
1823
16th to endDay
17%6%35%424445%40%
2208
April1st to 15thDay
22%9%35%424335%34%
2152
16th to endDay
20%7%45%5%24346%35%
2246
May1st to 15thDay
20%7%36%5%34346%33%
2511
16th to endDay
19%6%245%3445%8%33%
2618
June1st to 15thDay
21%6%35%5%35%45%7%30%
2520
16th to endDay
18%5%25%435%6%7%8%30%
2520
July1st to 15thDay
13%425%5%35%5%7%8%37%
2520
16th to endDay
11%5%35%6%36%6%7%9%35%
2654
August1st to 15thDay
11%6%36%6%35%6%5%7%37%
2469
16th to endDay
10%435%5%35%5%5%8%44%
2315
September1st to 15thDay
17%42443445%7%41%
2160
16th to endDay
16%424323337%47%
1925
October1st to 15thDay
21%8%34424346%35%
1650
16th to endDay
26%9%48%5%4435%424%
1650
November1st to 15thDay
16%8%36%6%35%447%33%
1545
16th to endDay
25%11%46%5%23435%26%
1440
December1st to 15thDay
23%13%5%8%6%35%445%19%
1440
16th to endDay
24%17%5%7%5%3433420%
1536
January1st to 15thNight
19%16%7%8%6%3444420%
2506
16th to endNight
14%16%5%8%6%35%445%25%
2670
February1st to 15thNight
12%12%7%11%7%36%5%45%23%
2285
16th to endNight
17%11%5%9%5%3445%428%
1931
March1st to 15thNight
20%10%47%7%34335%28%
2114
16th to endNight
15%8%36%5%2333442%
2016
April1st to 15thNight
24%7%34423345%34%
1796
16th to endNight
19%8%35%414445%37%
1725
May1st to 15thNight
22%7%36%41434436%
1440
16th to endNight
17%6%244245%5%6%37%
1495
June1st to 15thNight
19%7%35%5%3446%7%31%
1440
16th to endNight
17%5%15%325%6%6%8%36%
1440
July1st to 15thNight
10%324335%47%8%45%
1440
16th to endNight
9%434425%5%5%9%44%
1514
August1st to 15thNight
10%6%245%35%7%7%8%39%
1488
16th to endNight
10%425%42445%7%49%
1874
September1st to 15thNight
14%6%25%6%34446%41%
1800
16th to endNight
16%414322346%49%
1870
October1st to 15thNight
19%7%25%42435%6%37%
1980
16th to endNight
24%9%36%6%33445%28%
2222
November1st to 15thNight
20%8%26%6%34345%33%
2310
16th to endNight
21%11%47%5%45%445%25%
2520
December1st to 15thNight
23%14%5%7%5%35%34422%
2520
16th to endNight
24%16%5%7%6%2433420%
2688

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%14%5%9%7%2434421%
1432
16th to endDay
14%15%5%8%5%35%45%5%25%
1554
February1st to 15thDay
14%12%5%11%7%36%445%24%
1575
16th to endDay
18%12%48%7%4434426%
1542
March1st to 15thDay
18%10%48%6%36%44427%
1833
16th to endDay
17%6%35%434445%39%
2207
April1st to 15thDay
22%10%35%423335%34%
2152
16th to endDay
19%8%35%5%34346%35%
2246
May1st to 15thDay
20%6%36%6%3435%5%33%
2511
16th to endDay
19%7%245%245%5%7%34%
2618
June1st to 15thDay
21%7%26%435%45%7%30%
2520
16th to endDay
18%5%25%436%6%6%9%30%
2520
July1st to 15thDay
13%425%5%35%6%6%9%36%
2520
16th to endDay
11%5%25%6%36%6%8%9%35%
2654
August1st to 15thDay
11%6%26%6%35%6%5%8%36%
2469
16th to endDay
9%5%245%35%45%8%44%
2315
September1st to 15thDay
16%5%134345%5%7%42%
2160
16th to endDay
16%5%23324347%47%
1925
October1st to 15thDay
20%9%25%434346%35%
1650
16th to endDay
24%10%39%5%34445%24%
1650
November1st to 15thDay
16%8%36%5%3445%6%34%
1545
16th to endDay
24%11%36%6%2235%5%26%
1440
December1st to 15thDay
24%13%5%7%6%36%445%19%
1440
16th to endDay
23%16%5%8%6%3433320%
1536
January1st to 15thNight
19%16%6%10%6%3433420%
2506
16th to endNight
14%16%48%6%35%445%26%
2670
February1st to 15thNight
13%12%6%11%8%36%5%5%5%22%
2278
16th to endNight
17%11%48%6%3445%428%
1931
March1st to 15thNight
20%10%5%7%6%3433428%
2127
16th to endNight
16%8%35%5%2334442%
2016
April1st to 15thNight
25%8%245%2334434%
1796
16th to endNight
20%8%26%5%24336%38%
1725
May1st to 15thNight
22%7%35%42335%5%35%
1440
16th to endNight
17%6%25%435%45%6%37%
1495
June1st to 15thNight
20%7%35%5%3447%7%30%
1440
16th to endNight
17%5%244346%6%8%36%
1440
July1st to 15thNight
10%325%335%46%9%45%
1440
16th to endNight
9%4345%345%6%8%44%
1514
August1st to 15thNight
10%5%346%35%5%7%9%38%
1488
16th to endNight
9%42442445%6%49%
1874
September1st to 15thNight
14%5%25%6%345%5%5%41%
1800
16th to endNight
16%413424345%49%
1870
October1st to 15thNight
18%8%35%424446%36%
1980
16th to endNight
24%9%36%5%33445%28%
2222
November1st to 15thNight
20%8%35%6%34436%33%
2310
16th to endNight
22%10%38%6%35%445%25%
2520
December1st to 15thNight
22%14%5%8%5%24335%21%
2520
16th to endNight
25%16%5%7%5%2344420%
2688

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
67%48%12%5%
1433
16th to endDay
60%5%10%14%8%
1554
February1st to 15thDay
61%6%10%17%4
1577
16th to endDay
61%49%14%9%1
1542
March1st to 15thDay
59%5%10%14%8%1
1833
16th to endDay
46%5%8%17%16%5%
2208
April1st to 15thDay
53%37%19%12%2
2152
16th to endDay
50%5%7%18%14%4
2246
May1st to 15thDay
52%5%6%19%14%1
2511
16th to endDay
48%7%11%18%12%1
2622
June1st to 15thDay
52%6%10%19%9%
2520
16th to endDay
47%8%12%19%10%1
2520
July1st to 15thDay
40%8%14%24%11%
2371
16th to endDay
43%9%15%21%9%
2487
August1st to 15thDay
44%9%15%21%9%
2455
16th to endDay
36%8%17%27%9%
2315
September1st to 15thDay
41%6%13%25%12%
2160
16th to endDay
38%6%13%32%10%
1925
October1st to 15thDay
50%5%11%20%11%
1650
16th to endDay
62%6%11%14%5%
1650
November1st to 15thDay
50%6%14%18%9%
1545
16th to endDay
60%5%11%15%6%
1440
December1st to 15thDay
66%7%11%11%2
1440
16th to endDay
69%410%10%6%
1536
January1st to 15thNight
67%5%10%11%4
2506
16th to endNight
60%410%15%7%
2670
February1st to 15thNight
62%5%10%16%5%
2287
16th to endNight
56%5%9%17%10%
1931
March1st to 15thNight
58%5%9%18%8%1
2127
16th to endNight
46%48%19%16%4
2016
April1st to 15thNight
52%38%17%15%1
1796
16th to endNight
47%5%8%17%17%3
1725
May1st to 15thNight
50%5%6%17%15%4
1440
16th to endNight
44%8%10%20%14%2
1497
June1st to 15thNight
50%8%10%20%9%
1440
16th to endNight
42%9%12%20%15%
1440
July1st to 15thNight
33%8%12%29%14%
1360
16th to endNight
36%7%15%25%14%
1418
August1st to 15thNight
38%11%17%23%9%
1478
16th to endNight
32%7%16%31%11%
1874
September1st to 15thNight
42%7%11%25%12%1
1800
16th to endNight
37%6%11%33%11%
1870
October1st to 15thNight
47%6%10%23%11%
1980
16th to endNight
57%7%12%17%5%
2222
November1st to 15thNight
53%413%17%9%1
2310
16th to endNight
60%6%10%16%4
2520
December1st to 15thNight
65%6%10%14%3
2520
16th to endNight
66%5%8%11%6%
2688

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
30%15%21%23%8%1
60
16th to endDay
34%429%25%41
67
February1st to 15thDay
28%20%35%14%1
90
16th to endDay
33%9%28%25%2
201
March1st to 15thDay
27%11%30%24%6%
270
16th to endDay
24%8%29%22%10%3
288
April1st to 15thDay
28%13%27%18%10%1
270
16th to endDay
20%14%26%22%14%2
270
May1st to 15thDay
28%9%27%21%8%4
288
16th to endDay
23%9%30%20%11%2
331
June1st to 15thDay
25%6%31%23%11%1
315
16th to endDay
20%7%24%30%15%1
315
July1st to 15thDay
14%5%24%28%19%7%
305
16th to endDay
13%319%34%23%5%
326
August1st to 15thDay
13%321%35%20%6%
313
16th to endDay
12%419%31%19%12%
332
September1st to 15thDay
20%5%18%21%21%13%
315
16th to endDay
19%7%18%19%20%16%
283
October1st to 15thDay
25%7%22%22%18%2
255
16th to endDay
32%9%23%23%9%
252
November1st to 15thDay
21%10%26%25%15%2
199
16th to endDay
35%10%25%26%3
60
December1st to 15thDay
30%10%30%25%5%
60
16th to endDay
43%12%35%7%
64
January1st to 15thNight
28%9%30%25%5%
720
16th to endNight
23%8%30%28%7%
768
February1st to 15thNight
19%8%38%27%6%
704
16th to endNight
25%7%32%27%6%
631
March1st to 15thNight
26%10%31%26%4
720
16th to endNight
19%8%31%29%10%
768
April1st to 15thNight
27%8%29%29%5%
718
16th to endNight
25%8%29%27%8%
645
May1st to 15thNight
28%424%31%9%1
360
16th to endNight
21%429%30%13%
375
June1st to 15thNight
21%325%40%9%
360
16th to endNight
18%126%36%15%1
360
July1st to 15thNight
11%121%42%21%
340
16th to endNight
12%217%44%22%1
376
August1st to 15thNight
14%214%39%26%2
407
16th to endNight
12%219%38%24%1
728
September1st to 15thNight
19%320%35%20%1
720
16th to endNight
20%418%29%24%2
689
October1st to 15thNight
23%5%28%28%12%
660
16th to endNight
29%6%27%27%7%
704
November1st to 15thNight
25%5%29%26%12%
700
16th to endNight
27%10%29%21%10%
720
December1st to 15thNight
31%9%30%23%5%
720
16th to endNight
34%8%32%18%41
768
Page generated at 2017-09-24 09:15:50. Version ac04

Copyright 2017 A. Danko


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