StarPines Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the StarPines Observatory clear sky chart from 2005-11-06 to 2024-02-20.

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
67%
24250
35%
79330
28%
24161
75%
24161
48%
37253

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 10thNight
60%
752
38%
3982
29%
736
71%
736
31%
1624
January11th to 20thNight
59%
753
42%
3907
32%
740
69%
740
38%
1365
January21st to endNight
50%
828
23%
4277
27%
814
65%
814
21%
2282
February1st to 10thNight
56%
760
36%
2375
28%
760
71%
760
44%
1169
February11th to 20thNight
54%
738
35%
2212
26%
738
68%
738
46%
1119
February21st to endNight
53%
592
36%
1776
30%
592
63%
592
41%
927
March1st to 10thNight
52%
720
34%
2007
22%
720
65%
720
45%
1059
March11th to 20thNight
59%
720
36%
1980
26%
720
68%
720
47%
1036
March21st to endNight
55%
792
35%
2178
21%
792
67%
792
49%
1114
April1st to 10thNight
55%
720
32%
1980
17%
720
67%
720
53%
983
April11th to 20thNight
50%
628
38%
1821
19%
628
67%
628
52%
846
April21st to endNight
55%
540
44%
1620
25%
540
72%
540
62%
686
May1st to 10thNight
63%
540
39%
1620
28%
540
72%
540
56%
717
May11th to 20thNight
67%
531
41%
1594
30%
531
75%
531
63%
671
May21st to endNight
69%
582
40%
1746
29%
582
76%
582
71%
697
June1st to 10thNight
73%
540
36%
1620
29%
540
77%
540
66%
680
June11th to 20thNight
74%
540
37%
1620
30%
540
78%
540
73%
646
June21st to endNight
80%
540
34%
1620
30%
540
82%
540
64%
705
July1st to 10thNight
82%
525
29%
1575
25%
525
83%
525
53%
768
July11th to 20thNight
85%
522
26%
1566
21%
522
85%
522
50%
774
July21st to endNight
77%
591
25%
1674
21%
558
79%
558
38%
945
August1st to 10thNight
85%
537
28%
1602
24%
534
86%
534
52%
781
August11th to 20thNight
86%
534
33%
1602
28%
534
86%
534
49%
786
August21st to endNight
84%
728
33%
1988
28%
728
84%
728
49%
1069
September1st to 10thNight
80%
720
32%
1980
28%
720
81%
720
51%
1029
September11th to 20thNight
86%
720
43%
1980
36%
720
89%
720
67%
914
September21st to endNight
77%
720
41%
1980
30%
720
84%
720
65%
913
October1st to 10thNight
71%
720
38%
1989
29%
720
77%
720
57%
980
October11th to 20thNight
75%
720
43%
2160
36%
720
82%
720
67%
909
October21st to endNight
71%
792
45%
2376
35%
792
82%
792
63%
1008
November1st to 10thNight
72%
740
41%
2254
34%
740
81%
740
57%
1019
November11th to 20thNight
70%
760
40%
2470
35%
760
81%
760
57%
1056
November21st to endNight
61%
760
38%
2470
32%
760
72%
760
46%
1171
December1st to 10thNight
65%
760
36%
2470
33%
760
72%
760
44%
1205
December11th to 20thNight
59%
758
33%
2935
30%
758
69%
758
31%
1590
December21st to endNight
54%
827
23%
4324
27%
817
65%
817
25%
2010

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
442442445%6%62%
78855
Night
3423323446%65%
80401
TransparencyDay
22%3415%28%27%
78582
Night
20%35%16%29%28%
80196
SeeingDay
7%12%26%30%18%6%
14014
Night
5%5%16%35%31%7%
24290

By Month

Percentage Cloud Cover SW (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 10thDay
45%35%433345%60%
2858
11th to 20thDay
34244345%45%62%
2860
21st to endDay
11%7%25%42445%7%48%
3146
February1st to 10thDay
47%23423345%62%
1800
11th to 20thDay
6%6%3443336%6%56%
1841
21st to endDay
48%2442445%6%58%
1480
March1st to 10thDay
35%245%345%5%7%57%
1952
11th to 20thDay
46%3442345%6%59%
1980
21st to endDay
4325%424345%64%
2178
April1st to 10thDay
232442345%7%64%
1980
11th to 20thDay
2313312346%72%
2081
21st to endDay
2213323447%69%
2340
May1st to 10thDay
3323323337%68%
2340
11th to 20thDay
3213223445%71%
2301
21st to endDay
231321233475%
2530
June1st to 10thDay
1112323246%75%
2340
11th to 20thDay
211111122385%
2340
21st to endDay
1212323335%74%
2340
July1st to 10thDay
2224436%5%6%6%62%
2340
11th to 20thDay
5%325%7%47%7%8%10%43%
2340
21st to endDay
7%5%27%7%6%7%9%10%9%32%
2545
August1st to 10thDay
5%4245%35%5%6%8%53%
2328
11th to 20thDay
4425%6%36%6%8%9%48%
2299
21st to endDay
5%425%435%6%7%8%51%
2361
September1st to 10thDay
6%3245%45%46%7%53%
1980
11th to 20thDay
3112323345%72%
1980
21st to endDay
3212423345%70%
1980
October1st to 10thDay
4313424345%67%
1969
11th to 20thDay
221221223479%
1800
21st to endDay
2212212335%76%
1980
November1st to 10thDay
2212324446%70%
1821
11th to 20thDay
2213323446%70%
1710
21st to endDay
5%5%24223436%64%
1710
December1st to 10thDay
6%7%235%34346%58%
1710
11th to 20thDay
5%8%25%6%345%7%7%48%
2169
21st to endDay
7%8%36%5%2345%6%52%
3146
January1st to 10thNight
34245%3445%6%60%
4097
11th to 20thNight
3313323447%67%
4110
21st to endNight
9%9%35%433446%50%
4521
February1st to 10thNight
46%24323345%63%
2375
11th to 20thNight
5%5%24423347%62%
2211
21st to endNight
5%7%2333345%5%60%
1776
March1st to 10thNight
45%2432346%6%60%
2007
11th to 20thNight
6%5%23323445%63%
1980
21st to endNight
332342445%6%64%
2178
April1st to 10thNight
33233235%5%6%66%
1980
11th to 20thNight
132342333473%
1821
21st to endNight
1212212335%76%
1620
May1st to 10thNight
2213323445%73%
1620
11th to 20thNight
221321223479%
1594
21st to endNight
22111133482%
1746
June1st to 10thNight
111221223479%
1620
11th to 20thNight
111211222384%
1620
21st to endNight
111332323476%
1620
July1st to 10thNight
22134245%6%7%63%
1620
11th to 20thNight
2213435%6%7%9%58%
1620
21st to endNight
4435%6%45%6%7%12%44%
1773
August1st to 10thNight
22133345%7%9%60%
1611
11th to 20thNight
1213445%5%8%11%56%
1602
21st to endNight
3213435%6%6%8%59%
1988
September1st to 10thNight
33234345%6%9%59%
1980
11th to 20thNight
2112313335%77%
1980
21st to endNight
223222235%77%
1980
October1st to 10thNight
4223323445%70%
1989
11th to 20thNight
221321222380%
2160
21st to endNight
1212212235%78%
2376
November1st to 10thNight
2322314335%72%
2254
11th to 20thNight
1313323336%73%
2470
21st to endNight
5%424323435%66%
2470
December1st to 10thNight
5%41333445%5%61%
2470
11th to 20thNight
6%6%25%5%35%5%5%7%51%
3041
21st to endNight
6%6%245%35%5%45%56%
4521

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 10thDay
26%2218%35%16%
2859
11th to 20thDay
25%2427%26%16%
2860
21st to endDay
37%2416%30%12%
3146
February1st to 10thDay
26%2415%26%27%
1800
11th to 20thDay
29%3216%28%23%
1851
21st to endDay
26%3417%27%24%
1480
March1st to 10thDay
26%3216%30%24%
1952
11th to 20thDay
27%2315%32%22%
1980
21st to endDay
23%2218%38%16%
2178
April1st to 10thDay
21%2217%34%24%
1980
11th to 20thDay
15%2213%35%33%
2084
21st to endDay
16%2114%36%30%
2340
May1st to 10thDay
17%3315%32%31%
2340
11th to 20thDay
15%3214%33%33%
2304
21st to endDay
13%2111%33%39%
2530
June1st to 10thDay
12%28%33%45%
2340
11th to 20thDay
8%2421%65%
2340
21st to endDay
13%317%22%54%
2340
July1st to 10thDay
20%5%5%14%19%38%
2276
11th to 20thDay
30%7%14%19%19%11%
2271
21st to endDay
36%8%16%19%13%8%
2404
August1st to 10thDay
26%5%8%17%20%23%
2313
11th to 20thDay
27%5%8%23%19%17%
2299
21st to endDay
27%6%8%18%27%15%
2361
September1st to 10thDay
27%5%5%16%23%24%
1980
11th to 20thDay
14%3313%34%32%
1980
21st to endDay
17%2311%32%36%
1980
October1st to 10thDay
20%3318%22%34%
1969
11th to 20thDay
11%129%33%43%
1800
21st to endDay
13%2313%32%37%
1980
November1st to 10thDay
16%2317%35%27%
1821
11th to 20thDay
16%2316%29%34%
1710
21st to endDay
23%2216%30%26%
1710
December1st to 10thDay
29%3417%22%25%
1710
11th to 20thDay
32%38%20%19%18%
2168
21st to endDay
33%3318%30%13%
3146
January1st to 10thNight
24%3315%38%17%
4097
11th to 20thNight
19%16%28%31%15%
4110
21st to endNight
36%2414%29%15%
4521
February1st to 10thNight
23%2416%26%28%
2375
11th to 20thNight
24%2417%29%24%
2212
21st to endNight
26%2313%31%26%
1776
March1st to 10thNight
24%2316%30%25%
2007
11th to 20thNight
23%2414%33%24%
1980
21st to endNight
20%35%18%34%19%
2178
April1st to 10thNight
19%2415%36%25%
1980
11th to 20thNight
16%2210%33%37%
1821
21st to endNight
11%2313%36%34%
1620
May1st to 10thNight
15%2315%29%36%
1620
11th to 20thNight
12%2211%35%38%
1595
21st to endNight
9%1112%36%41%
1746
June1st to 10thNight
12%25%29%52%
1620
11th to 20thNight
8%21420%65%
1620
21st to endNight
13%215%19%59%
1620
July1st to 10thNight
18%5%7%11%20%40%
1575
11th to 20thNight
20%5%15%20%26%14%
1566
21st to endNight
28%7%16%23%17%10%
1674
August1st to 10thNight
18%5%13%17%20%27%
1602
11th to 20thNight
21%412%24%17%21%
1602
21st to endNight
23%5%7%22%26%18%
1988
September1st to 10thNight
21%410%19%21%26%
1980
11th to 20thNight
12%3313%31%38%
1980
21st to endNight
13%2311%31%39%
1980
October1st to 10thNight
18%2417%23%36%
1989
11th to 20thNight
12%1210%29%46%
2160
21st to endNight
12%2412%27%44%
2376
November1st to 10thNight
16%2216%36%28%
2254
11th to 20thNight
16%2314%31%35%
2470
21st to endNight
22%2215%30%30%
2470
December1st to 10thNight
24%25%18%24%28%
2470
11th to 20thNight
32%3417%25%19%
3041
21st to endNight
30%3419%27%17%
4521

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 10thDay
18%12%23%30%15%1
270
11th to 20thDay
13%7%29%31%16%4
270
21st to endDay
8%19%25%24%19%5%
297
February1st to 10thDay
10%19%30%25%14%3
360
11th to 20thDay
14%21%31%25%8%
452
21st to endDay
16%23%32%20%8%1
346
March1st to 10thDay
12%24%34%22%8%
420
11th to 20thDay
12%19%29%26%10%3
420
21st to endDay
12%26%33%18%9%1
462
April1st to 10thDay
8%18%36%21%14%3
420
11th to 20thDay
10%25%36%16%10%3
412
21st to endDay
6%25%34%20%10%4
420
May1st to 10thDay
8%18%38%24%9%4
423
11th to 20thDay
318%35%27%13%5%
448
21st to endDay
8%16%33%29%11%4
485
June1st to 10thDay
210%36%31%16%5%
450
11th to 20thDay
5%11%35%30%14%6%
450
21st to endDay
16%32%37%17%6%
450
July1st to 10thDay
323%43%23%8%
446
11th to 20thDay
4211%37%29%16%
444
21st to endDay
6%48%36%32%15%
487
August1st to 10thDay
4215%40%27%13%
447
11th to 20thDay
3310%43%27%13%
437
21st to endDay
6%111%35%33%15%
495
September1st to 10thDay
5%419%39%21%12%
450
11th to 20thDay
4328%36%21%7%
450
21st to endDay
5%10%22%37%18%8%
450
October1st to 10thDay
6%12%27%28%22%4
439
11th to 20thDay
47%24%32%28%4
270
21st to endDay
413%21%32%23%6%
297
November1st to 10thDay
7%9%23%36%22%3
270
11th to 20thDay
5%12%21%33%22%6%
270
21st to endDay
10%9%27%29%20%4
270
December1st to 10thDay
12%10%22%33%22%1
270
11th to 20thDay
315%27%36%17%3
270
21st to endDay
16%13%24%29%15%2
297
January1st to 10thNight
9%5%19%40%19%8%
760
11th to 20thNight
7%6%21%37%23%7%
760
21st to endNight
13%8%20%34%20%4
836
February1st to 10thNight
7%9%21%35%23%4
760
11th to 20thNight
7%8%23%41%18%2
742
21st to endNight
11%8%23%38%17%4
592
March1st to 10thNight
8%8%26%38%18%2
720
11th to 20thNight
9%7%19%31%28%6%
720
21st to endNight
6%8%25%36%22%2
792
April1st to 10thNight
38%26%40%20%3
720
11th to 20thNight
412%27%32%22%3
628
21st to endNight
29%31%32%22%4
540
May1st to 10thNight
36%22%41%24%3
540
11th to 20thNight
26%20%38%29%4
531
21st to endNight
35%20%41%28%4
584
June1st to 10thNight
2416%41%35%2
540
11th to 20thNight
1218%41%31%6%
540
21st to endNight
1110%38%44%5%
540
July1st to 10thNight
217%34%48%8%
525
11th to 20thNight
2323%54%16%
522
21st to endNight
42219%56%16%
591
August1st to 10thNight
3419%57%17%
537
11th to 20thNight
31321%58%14%
534
21st to endNight
32220%53%21%
728
September1st to 10thNight
42426%48%16%
720
11th to 20thNight
217%33%49%8%
720
21st to endNight
3313%33%40%8%
720
October1st to 10thNight
5%315%40%34%4
720
11th to 20thNight
3215%41%33%6%
720
21st to endNight
35%16%33%31%12%
792
November1st to 10thNight
4415%40%30%7%
740
11th to 20thNight
3419%38%29%8%
760
21st to endNight
8%5%19%35%27%6%
760
December1st to 10thNight
8%6%15%38%29%4
760
11th to 20thNight
11%5%16%41%23%4
760
21st to endNight
9%8%20%40%18%4
836
Page generated at 2024-02-17 04:28:38. Version ac07

Copyright 2024 Attilla Danko


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