Ghost Pine Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ghost Pine Observatory clear sky chart from 2005-11-05 to 2019-06-02.

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
65%
17508
30%
53862
24%
17467
72%
17467
43%
27665

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
51%
840
20%
2827
17%
836
57%
836
25%
1717
January16th to endNight
52%
896
24%
2912
19%
896
60%
896
27%
1757
February1st to 15thNight
52%
818
26%
2678
20%
817
62%
817
28%
1585
February16th to endNight
51%
736
25%
2235
19%
736
60%
736
33%
1278
March1st to 15thNight
51%
840
17%
2346
13%
840
56%
840
28%
1524
March16th to endNight
49%
896
22%
2437
13%
896
57%
896
34%
1507
April1st to 15thNight
50%
839
24%
2099
9%
839
57%
839
35%
1343
April16th to endNight
61%
832
28%
2080
13%
832
66%
832
54%
1099
May1st to 15thNight
67%
656
33%
1916
22%
656
73%
656
60%
858
May16th to endNight
73%
438
28%
1752
29%
438
79%
438
51%
692
June1st to 15thNight
74%
392
31%
1568
35%
392
83%
392
53%
587
June16th to endNight
84%
390
36%
1560
47%
390
89%
390
70%
500
July1st to 15thNight
93%
370
37%
1480
50%
370
94%
370
75%
454
July16th to endNight
94%
608
39%
1733
37%
575
95%
575
84%
637
August1st to 15thNight
94%
574
42%
1719
35%
571
94%
571
80%
657
August16th to endNight
95%
819
44%
2061
29%
819
95%
819
86%
888
September1st to 15thNight
90%
780
45%
1950
32%
780
92%
780
83%
865
September16th to endNight
86%
776
45%
2130
39%
776
90%
776
76%
905
October1st to 15thNight
70%
780
35%
2340
30%
780
80%
780
55%
1059
October16th to endNight
70%
832
37%
2496
33%
832
78%
832
54%
1181
November1st to 15thNight
64%
820
30%
2583
26%
820
72%
820
42%
1315
November16th to endNight
57%
840
24%
2884
23%
840
63%
840
30%
1600
December1st to 15thNight
51%
840
22%
2940
17%
840
61%
840
25%
1745
December16th to endNight
46%
896
22%
3136
16%
896
57%
896
22%
1912

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
6%312212346%64%
54473
Night
7%212223346%63%
54046
TransparencyDay
22%49%19%25%18%
54156
Night
23%49%19%24%19%
53863
SeeingDay
8%7%18%25%26%13%
8101
Night
8%416%30%33%6%
17516

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 15thDay
16%6%34433346%43%
1770
16th to endDay
13%5%35%43335%6%46%
2016
February1st to 15thDay
14%6%24323246%49%
1846
16th to endDay
13%41443445%7%46%
1809
March1st to 15thDay
13%5%35%5%3446%8%39%
2271
16th to endDay
11%5%245%2445%7%45%
2490
April1st to 15thDay
11%5%25%5%3435%8%43%
2509
16th to endDay
322232345%7%63%
2485
May1st to 15thDay
321212248%70%
2690
16th to endDay
321332345%7%61%
3063
June1st to 15thDay
3112213446%69%
2746
16th to endDay
111122385%
2730
July1st to 15thDay
1112287%
2730
16th to endDay
111388%
2678
August1st to 15thDay
1112385%
2484
16th to endDay
111289%
2492
September1st to 15thDay
111112384%
2340
16th to endDay
21111113480%
2156
October1st to 15thDay
4212212245%71%
1950
16th to endDay
6%312212336%66%
2080
November1st to 15thDay
7%2133235%6%8%56%
1933
16th to endDay
10%424424346%52%
1733
December1st to 15thDay
13%6%34334337%46%
1680
16th to endDay
15%6%3441345%8%41%
1792
January1st to 15thNight
13%5%2433345%8%44%
2827
16th to endNight
13%424324436%48%
2912
February1st to 15thNight
12%42442445%7%46%
2666
16th to endNight
12%412314447%52%
2235
March1st to 15thNight
12%5%245%245%5%7%44%
2346
16th to endNight
11%5%24324346%51%
2437
April1st to 15thNight
6%425%5%35%447%51%
2099
16th to endNight
5%112212247%68%
2080
May1st to 15thNight
211212337%72%
1916
16th to endNight
31121245%6%70%
1752
June1st to 15thNight
3111112235%75%
1568
16th to endNight
111112384%
1560
July1st to 15thNight
1111287%
1560
16th to endNight
112288%
1840
August1st to 15thNight
1111188%
1728
16th to endNight
1111289%
2061
September1st to 15thNight
111112386%
1950
16th to endNight
111125%83%
2130
October1st to 15thNight
411112245%72%
2340
16th to endNight
5%112212346%68%
2496
November1st to 15thNight
6%21332235%8%58%
2583
16th to endNight
9%324423447%53%
2884
December1st to 15thNight
13%5%24423347%47%
2940
16th to endNight
14%4233345%5%7%45%
3136

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
43%5%12%16%14%7%
1770
16th to endDay
39%6%9%14%19%10%
2016
February1st to 15thDay
37%411%19%21%5%
1846
16th to endDay
38%5%10%25%15%4
1809
March1st to 15thDay
42%6%14%17%12%6%
2271
16th to endDay
38%6%14%18%17%4
2490
April1st to 15thDay
39%6%13%19%17%3
2509
16th to endDay
20%5%14%25%25%8%
2485
May1st to 15thDay
14%310%28%32%11%
2690
16th to endDay
20%6%14%29%20%9%
3067
June1st to 15thDay
16%49%23%25%19%
2746
16th to endDay
6%2415%36%34%
2730
July1st to 15thDay
5%1210%31%48%
2581
16th to endDay
41314%28%48%
2522
August1st to 15thDay
5%1412%37%38%
2468
16th to endDay
4316%39%35%
2492
September1st to 15thDay
6%15%13%34%38%
2340
16th to endDay
9%26%23%31%25%
2156
October1st to 15thDay
16%27%20%28%24%
1950
16th to endDay
21%37%24%27%14%
2080
November1st to 15thDay
24%6%12%28%18%9%
1933
16th to endDay
33%5%13%20%20%6%
1733
December1st to 15thDay
38%5%9%18%20%6%
1680
16th to endDay
40%6%10%19%17%5%
1792
January1st to 15thNight
38%5%11%21%15%8%
2827
16th to endNight
36%5%10%15%18%12%
2912
February1st to 15thNight
36%410%18%19%9%
2678
16th to endNight
31%414%23%21%4
2235
March1st to 15thNight
38%6%15%15%17%6%
2346
16th to endNight
34%411%22%20%6%
2437
April1st to 15thNight
32%7%13%21%17%7%
2099
16th to endNight
16%413%28%28%8%
2080
May1st to 15thNight
12%39%26%33%14%
1917
16th to endNight
13%5%15%33%21%10%
1752
June1st to 15thNight
12%49%25%28%19%
1568
16th to endNight
7%2315%31%40%
1560
July1st to 15thNight
6%16%30%53%
1480
16th to endNight
41310%22%57%
1733
August1st to 15thNight
6%210%31%48%
1719
16th to endNight
5%213%35%43%
2061
September1st to 15thNight
6%1410%34%44%
1950
16th to endNight
7%25%20%32%32%
2130
October1st to 15thNight
14%38%19%27%26%
2340
16th to endNight
17%37%23%26%21%
2496
November1st to 15thNight
23%5%13%26%20%11%
2583
16th to endNight
31%5%10%20%22%9%
2884
December1st to 15thNight
36%6%9%17%20%9%
2940
16th to endNight
38%7%10%17%20%6%
3136

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
27%7%24%23%15%
218
16th to endDay
14%10%24%22%21%6%
352
February1st to 15thDay
19%12%23%25%15%4
326
16th to endDay
16%12%27%26%11%5%
333
March1st to 15thDay
18%14%24%23%13%6%
390
16th to endDay
12%16%22%29%14%4
416
April1st to 15thDay
14%16%28%21%12%6%
389
16th to endDay
6%12%24%23%21%11%
378
May1st to 15thDay
7%6%23%30%22%10%
408
16th to endDay
6%5%19%25%25%17%
458
June1st to 15thDay
37%18%25%32%11%
380
16th to endDay
214%33%35%13%
375
July1st to 15thDay
25%25%46%19%
365
16th to endDay
6%25%41%25%
391
August1st to 15thDay
27%23%40%24%
359
16th to endDay
6%21%38%33%
396
September1st to 15thDay
27%30%39%19%
375
16th to endDay
2415%23%36%18%
375
October1st to 15thDay
5%11%20%27%23%10%
375
16th to endDay
9%5%16%27%28%14%
400
November1st to 15thDay
10%5%18%23%33%9%
259
16th to endDay
16%7%20%26%20%8%
135
December1st to 15thDay
24%9%18%24%14%10%
120
16th to endDay
10%12%28%19%25%3
128
January1st to 15thNight
16%5%18%31%21%5%
840
16th to endNight
14%5%21%31%20%6%
896
February1st to 15thNight
15%7%18%32%22%3
824
16th to endNight
14%8%19%33%19%4
736
March1st to 15thNight
15%7%19%30%24%3
840
16th to endNight
13%6%24%32%20%2
896
April1st to 15thNight
8%7%26%34%20%3
839
16th to endNight
5%7%22%32%25%6%
832
May1st to 15thNight
3421%32%33%5%
657
16th to endNight
3317%31%41%3
439
June1st to 15thNight
3316%33%42%1
392
16th to endNight
19%44%41%2
390
July1st to 15thNight
229%61%5%
370
16th to endNight
1220%63%12%
608
August1st to 15thNight
2224%59%11%
574
16th to endNight
226%61%9%
819
September1st to 15thNight
15%26%55%10%
780
16th to endNight
128%32%42%12%
776
October1st to 15thNight
46%15%33%31%7%
780
16th to endNight
6%217%25%36%11%
832
November1st to 15thNight
7%319%28%34%6%
820
16th to endNight
11%5%17%35%22%6%
840
December1st to 15thNight
15%6%19%30%22%5%
840
16th to endNight
16%9%21%29%21%1
896
Page generated at 2019-06-02 16:43:06. Version ac04

Copyright 2019 A. Danko


Ghost Pine Observatory Clear Sky Chart |Charts Home