Solis Lacus Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Solis Lacus Observatory clear sky chart from 2005-11-05 to 2018-03-21.

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
28%
15657
15%
49234
8%
15626
35%
15626
16%
34543

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
16%
780
10%
2716
5%
776
23%
776
8%
2093
January16th to endNight
15%
832
11%
2769
5%
832
24%
832
9%
2107
February1st to 15thNight
12%
764
9%
2482
3%
761
20%
761
8%
1964
February16th to endNight
16%
683
13%
2071
5%
683
26%
683
11%
1587
March1st to 15thNight
17%
780
12%
2252
6%
780
25%
780
11%
1716
March16th to endNight
20%
792
19%
2109
6%
792
29%
792
16%
1505
April1st to 15thNight
18%
718
14%
1796
4%
718
23%
718
17%
1328
April16th to endNight
25%
720
17%
1800
4%
720
32%
720
22%
1229
May1st to 15thNight
30%
413
18%
1493
11%
413
41%
413
13%
992
May16th to endNight
35%
374
18%
1497
14%
374
49%
374
18%
904
June1st to 15thNight
34%
360
14%
1440
13%
360
44%
360
16%
916
June16th to endNight
43%
360
14%
1440
13%
360
53%
360
22%
797
July1st to 15thNight
53%
340
13%
1360
17%
340
57%
340
23%
780
July16th to endNight
50%
376
17%
1418
18%
354
59%
354
24%
788
August1st to 15thNight
52%
536
15%
1607
10%
534
56%
534
27%
993
August16th to endNight
57%
752
20%
1898
12%
752
59%
752
35%
1205
September1st to 15thNight
46%
720
19%
1800
10%
720
49%
720
29%
1221
September16th to endNight
48%
717
26%
1953
17%
717
54%
717
31%
1236
October1st to 15thNight
35%
720
19%
2160
15%
720
42%
720
21%
1445
October16th to endNight
24%
768
14%
2352
8%
768
33%
768
16%
1692
November1st to 15thNight
28%
760
17%
2472
11%
760
36%
760
17%
1688
November16th to endNight
21%
780
16%
2707
8%
780
32%
780
12%
1873
December1st to 15thNight
17%
780
8%
2730
4%
780
21%
780
7%
2114
December16th to endNight
12%
832
7%
2912
3%
832
18%
832
6%
2370

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
16%9%47%6%35%5%5%6%30%
49623
Night
15%9%47%6%35%45%6%32%
49404
Cloud CoverDay
16%9%47%6%35%5%5%6%30%
49632
Night
15%9%47%6%3445%6%32%
49409
TransparencyDay
54%310%20%10%1
49311
Night
52%311%20%10%
49234
SeeingDay
22%17%24%18%11%4
6172
Night
19%23%22%23%10%
15658

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
15%10%6%13%6%46%5%45%21%
1552
16th to endDay
11%11%6%13%9%5%5%5%5%6%20%
1806
February1st to 15thDay
15%14%6%12%9%45%445%17%
1710
16th to endDay
17%12%5%9%8%35%445%22%
1688
March1st to 15thDay
17%14%5%9%7%24345%23%
2024
16th to endDay
16%12%46%6%345%46%29%
2243
April1st to 15thDay
19%11%5%5%5%34346%31%
2152
16th to endDay
16%9%36%5%24436%38%
2160
May1st to 15thDay
20%7%25%5%36%45%6%32%
2469
16th to endDay
16%6%36%6%25%45%8%33%
2618
June1st to 15thDay
21%6%25%5%35%5%5%8%29%
2520
16th to endDay
15%7%25%5%35%5%5%9%32%
2520
July1st to 15thDay
10%5%36%7%46%5%7%9%32%
2520
16th to endDay
12%5%26%6%35%6%7%8%35%
2654
August1st to 15thDay
15%6%25%5%46%7%7%8%30%
2340
16th to endDay
14%6%35%5%46%5%6%7%34%
2292
September1st to 15thDay
17%7%35%5%35%5%46%36%
2160
16th to endDay
14%6%245%24445%43%
2004
October1st to 15thDay
18%8%36%5%3345%6%34%
1800
16th to endDay
20%10%37%6%4445%6%26%
1872
November1st to 15thDay
16%10%36%5%44447%33%
1716
16th to endDay
18%12%37%8%235%46%28%
1579
December1st to 15thDay
16%16%7%9%6%35%435%21%
1560
16th to endDay
18%15%9%11%8%34435%15%
1664
January1st to 15thNight
16%11%5%10%8%45%5%6%6%20%
2716
16th to endNight
13%11%5%10%8%46%5%5%6%22%
2769
February1st to 15thNight
14%12%6%10%9%46%5%4420%
2480
16th to endNight
15%11%411%7%36%446%23%
2071
March1st to 15thNight
17%11%5%7%7%3435%5%26%
2240
16th to endNight
16%11%47%5%14346%33%
2109
April1st to 15thNight
21%10%36%5%24446%32%
1796
16th to endNight
18%7%24424346%42%
1800
May1st to 15thNight
17%7%26%5%25%45%7%34%
1493
16th to endNight
12%6%25%5%25%46%8%39%
1495
June1st to 15thNight
20%6%34424447%37%
1440
16th to endNight
10%4145%25%5%6%8%43%
1440
July1st to 15thNight
7%426%436%5%6%8%44%
1440
16th to endNight
11%415%425%5%6%9%43%
1514
August1st to 15thNight
10%5%25%4346%6%8%42%
1617
16th to endNight
11%424424447%47%
1898
September1st to 15thNight
14%425%43445%7%42%
1800
16th to endNight
13%4244245%47%46%
1953
October1st to 15thNight
18%8%25%5%23346%38%
2160
16th to endNight
21%9%36%6%34247%29%
2352
November1st to 15thNight
14%11%37%42445%6%34%
2472
16th to endNight
15%12%45%5%35%45%6%31%
2707
December1st to 15thNight
18%13%6%8%7%345%5%6%20%
2730
16th to endNight
18%14%8%10%6%45%5%5%5%16%
2912

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
14%9%6%13%7%36%5%45%21%
1552
16th to endDay
11%12%6%13%10%45%445%20%
1806
February1st to 15thDay
15%14%6%11%9%45%445%17%
1710
16th to endDay
17%12%49%9%34445%23%
1688
March1st to 15thDay
17%15%5%9%6%34445%24%
2034
16th to endDay
16%12%5%6%6%245%45%30%
2242
April1st to 15thDay
19%11%46%6%23345%31%
2152
16th to endDay
16%9%36%424435%38%
2160
May1st to 15thDay
20%7%26%5%36%35%7%31%
2469
16th to endDay
16%7%35%6%35%5%5%7%33%
2618
June1st to 15thDay
21%5%25%6%45%5%6%7%29%
2520
16th to endDay
15%7%25%5%35%6%410%32%
2520
July1st to 15thDay
11%5%26%7%47%5%7%9%33%
2520
16th to endDay
12%5%26%6%35%6%6%8%35%
2654
August1st to 15thDay
16%5%26%5%45%7%6%8%31%
2340
16th to endDay
14%5%35%6%35%5%6%8%34%
2292
September1st to 15thDay
17%7%26%5%25%45%6%35%
2160
16th to endDay
14%7%245%3345%6%42%
2004
October1st to 15thDay
18%8%46%5%3335%6%35%
1800
16th to endDay
20%11%37%6%4345%5%26%
1872
November1st to 15thDay
16%10%35%6%35%446%33%
1716
16th to endDay
18%11%37%6%3445%5%28%
1579
December1st to 15thDay
15%16%7%9%6%35%5%35%21%
1560
16th to endDay
18%14%9%11%8%3434416%
1664
January1st to 15thNight
15%12%411%7%35%46%6%20%
2716
16th to endNight
13%12%5%10%9%45%5%46%22%
2769
February1st to 15thNight
14%12%6%10%8%46%6%4420%
2473
16th to endNight
15%12%411%7%35%5%46%23%
2071
March1st to 15thNight
18%12%5%7%7%34345%27%
2252
16th to endNight
15%11%46%5%2345%6%34%
2109
April1st to 15thNight
20%10%35%5%24446%32%
1796
16th to endNight
18%7%245%23345%42%
1800
May1st to 15thNight
17%7%26%6%35%45%7%34%
1493
16th to endNight
12%6%25%5%25%46%7%40%
1495
June1st to 15thNight
20%6%35%424447%37%
1440
16th to endNight
10%3245%35%5%6%9%43%
1440
July1st to 15thNight
7%426%445%5%6%9%43%
1440
16th to endNight
11%414425%5%5%9%43%
1514
August1st to 15thNight
9%5%15%5%336%6%9%42%
1617
16th to endNight
11%5%245%2435%7%47%
1898
September1st to 15thNight
14%5%25%4235%5%7%43%
1800
16th to endNight
14%42442445%7%46%
1953
October1st to 15thNight
18%7%25%5%23337%38%
2160
16th to endNight
21%9%37%6%33346%30%
2352
November1st to 15thNight
14%11%36%5%2445%6%34%
2472
16th to endNight
15%12%45%5%345%5%6%31%
2707
December1st to 15thNight
18%13%6%9%6%35%446%20%
2730
16th to endNight
17%13%8%10%6%45%5%46%16%
2912

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
65%29%14%6%1
1553
16th to endDay
65%211%12%6%
1806
February1st to 15thDay
70%36%13%6%
1712
16th to endDay
63%38%17%7%
1688
March1st to 15thDay
62%211%14%6%
2034
16th to endDay
54%28%19%12%1
2243
April1st to 15thDay
54%37%22%9%2
2152
16th to endDay
49%27%21%16%2
2160
May1st to 15thDay
52%39%23%10%1
2469
16th to endDay
49%412%20%12%
2622
June1st to 15thDay
52%411%22%9%
2520
16th to endDay
47%5%12%23%10%1
2520
July1st to 15thDay
47%5%11%23%11%1
2371
16th to endDay
43%415%24%11%
2487
August1st to 15thDay
48%412%22%10%
2327
16th to endDay
45%410%26%12%1
2292
September1st to 15thDay
48%48%22%14%1
2160
16th to endDay
42%29%25%18%1
2004
October1st to 15thDay
50%39%21%13%1
1800
16th to endDay
58%212%18%6%
1872
November1st to 15thDay
52%312%19%10%2
1716
16th to endDay
57%211%18%8%
1579
December1st to 15thDay
65%211%14%4
1560
16th to endDay
72%210%10%3
1664
January1st to 15thNight
63%410%13%7%
2716
16th to endNight
62%310%16%6%
2769
February1st to 15thNight
65%49%13%6%
2482
16th to endNight
61%29%15%8%1
2071
March1st to 15thNight
59%311%17%7%
2252
16th to endNight
51%39%21%12%1
2109
April1st to 15thNight
54%210%19%12%1
1796
16th to endNight
45%210%22%17%2
1800
May1st to 15thNight
49%48%21%14%1
1493
16th to endNight
42%312%26%13%1
1497
June1st to 15thNight
47%312%25%10%
1440
16th to endNight
35%418%29%11%
1440
July1st to 15thNight
36%5%14%26%15%1
1360
16th to endNight
36%416%26%14%2
1418
August1st to 15thNight
37%417%28%11%
1607
16th to endNight
36%314%29%15%
1898
September1st to 15thNight
40%411%25%15%1
1800
16th to endNight
37%39%28%19%1
1953
October1st to 15thNight
47%310%23%14%1
2160
16th to endNight
55%213%19%8%
2352
November1st to 15thNight
50%312%18%12%2
2472
16th to endNight
53%313%21%8%
2707
December1st to 15thNight
65%312%13%5%
2730
16th to endNight
68%410%12%3
2912

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
28%24%31%12%21
90
16th to endDay
26%23%33%13%3
129
February1st to 15thDay
30%31%31%6%
135
16th to endDay
31%30%24%10%2
269
March1st to 15thDay
30%24%26%13%4
330
16th to endDay
25%27%24%14%5%2
311
April1st to 15thDay
30%23%24%12%6%2
270
16th to endDay
21%24%26%11%11%5%
270
May1st to 15thDay
31%21%20%13%9%3
288
16th to endDay
18%17%27%21%10%4
331
June1st to 15thDay
23%16%25%22%10%2
315
16th to endDay
20%15%30%21%11%2
315
July1st to 15thDay
14%10%25%26%18%4
305
16th to endDay
15%11%23%25%19%4
326
August1st to 15thDay
16%10%21%23%18%9%
313
16th to endDay
11%8%18%28%15%17%
332
September1st to 15thDay
16%13%19%19%22%9%
315
16th to endDay
14%9%20%19%19%15%
314
October1st to 15thDay
24%11%20%21%17%5%
315
16th to endDay
28%17%26%17%8%
324
November1st to 15thDay
23%18%17%25%14%1
280
16th to endDay
27%17%33%15%6%
109
December1st to 15thDay
26%16%33%15%5%2
90
16th to endDay
40%19%28%11%
96
January1st to 15thNight
20%32%26%16%3
780
16th to endNight
19%30%27%19%2
832
February1st to 15thNight
22%30%27%17%1
764
16th to endNight
24%28%25%17%3
683
March1st to 15thNight
26%29%21%18%3
780
16th to endNight
19%30%24%18%6%
792
April1st to 15thNight
25%28%23%18%3
718
16th to endNight
20%26%23%17%10%
720
May1st to 15thNight
21%22%20%26%9%
413
16th to endNight
10%22%23%31%11%1
375
June1st to 15thNight
20%20%17%30%10%1
360
16th to endNight
10%19%20%34%14%
360
July1st to 15thNight
7%13%19%41%16%1
340
16th to endNight
9%17%13%39%19%1
376
August1st to 15thNight
11%10%16%33%24%2
536
16th to endNight
10%10%12%33%29%3
752
September1st to 15thNight
15%12%18%30%21%1
720
16th to endNight
14%13%17%23%25%5%
717
October1st to 15thNight
22%15%17%27%16%
720
16th to endNight
25%18%25%24%5%
768
November1st to 15thNight
18%22%24%23%9%1
760
16th to endNight
23%27%23%17%6%
780
December1st to 15thNight
25%30%21%17%3
780
16th to endNight
25%31%27%13%3
832
Page generated at 2018-03-22 11:34:25. Version ac04

Copyright 2018 A. Danko


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