Sky Pony Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sky Pony 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
60%
17667
31%
53955
22%
17627
69%
17627
42%
28052

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
49%
836
35%
2508
21%
836
63%
836
42%
1321
January16th to endNight
51%
896
36%
2688
22%
896
65%
896
44%
1346
February1st to 15thNight
53%
822
36%
2469
22%
818
68%
818
47%
1210
February16th to endNight
42%
736
33%
2206
16%
736
57%
736
44%
1086
March1st to 15thNight
47%
840
33%
2486
18%
840
60%
840
43%
1273
March16th to endNight
49%
764
35%
2332
20%
764
63%
764
46%
1146
April1st to 15thNight
47%
629
36%
2098
23%
629
65%
629
40%
1002
April16th to endNight
49%
624
35%
2079
24%
624
67%
624
48%
928
May1st to 15thNight
49%
629
29%
2099
23%
629
63%
629
43%
1016
May16th to endNight
59%
657
26%
2076
24%
657
68%
657
41%
1072
June1st to 15thNight
71%
588
25%
1764
23%
588
76%
588
46%
910
June16th to endNight
75%
585
24%
1755
23%
585
77%
585
40%
970
July1st to 15thNight
76%
555
17%
1839
20%
555
77%
555
34%
1046
July16th to endNight
80%
612
21%
1931
24%
579
81%
579
35%
1085
August1st to 15thNight
84%
575
23%
1908
29%
572
84%
572
38%
1020
August16th to endNight
78%
621
19%
2070
22%
621
78%
621
29%
1238
September1st to 15thNight
75%
585
21%
1955
23%
585
75%
585
29%
1179
September16th to endNight
72%
582
24%
2145
27%
582
74%
582
28%
1253
October1st to 15thNight
69%
618
31%
2178
30%
618
72%
618
39%
1093
October16th to endNight
68%
832
36%
2496
25%
832
74%
832
52%
1206
November1st to 15thNight
65%
907
39%
2547
23%
907
72%
907
58%
1210
November16th to endNight
61%
1050
39%
2730
21%
1050
70%
1050
56%
1396
December1st to 15thNight
53%
1050
36%
2730
19%
1050
62%
1050
45%
1531
December16th to endNight
46%
1074
36%
2866
18%
1074
58%
1074
45%
1515

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
432443445%7%54%
54325
Night
431342445%8%57%
54178
Cloud CoverDay
43244345%5%7%53%
54323
Night
331342445%7%57%
54178
TransparencyDay
25%5%9%17%24%17%
54045
Night
22%5%10%18%24%18%
53960
SeeingDay
6%9%23%30%23%6%
7383
Night
5%6%21%37%25%3
17676

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
4423314447%58%
2090
16th to endDay
3313323445%62%
2240
February1st to 15thDay
2213423446%63%
2050
16th to endDay
2213223346%67%
1840
March1st to 15thDay
34245%3445%6%55%
2131
16th to endDay
2413323447%62%
2593
April1st to 15thDay
2213325%346%61%
2510
16th to endDay
2213212237%69%
2486
May1st to 15thDay
332332335%6%62%
2511
16th to endDay
321222345%7%63%
2737
June1st to 15thDay
111332447%8%60%
2549
16th to endDay
5%2245%25%6%7%10%47%
2527
July1st to 15thDay
9%435%6%5%8%7%8%9%30%
2340
16th to endDay
6%425%7%5%8%7%8%8%33%
2469
August1st to 15thDay
6%425%5%5%7%7%9%12%33%
2294
16th to endDay
7%5%36%8%5%6%6%7%9%32%
2484
September1st to 15thDay
11%6%36%6%46%6%5%7%34%
2334
16th to endDay
10%6%25%6%35%5%5%7%42%
2145
October1st to 15thDay
5%31432335%8%58%
2108
16th to endDay
5%21331324466%
2080
November1st to 15thDay
3312213435%67%
1955
16th to endDay
431331223469%
1890
December1st to 15thDay
5%423423347%57%
1890
16th to endDay
241322345%7%61%
2072
January1st to 15thNight
3425%42335%6%58%
2508
16th to endNight
4313323447%61%
2688
February1st to 15thNight
231332445%7%61%
2462
16th to endNight
321332445%8%62%
2206
March1st to 15thNight
4313325%45%7%57%
2486
16th to endNight
3323423446%62%
2332
April1st to 15thNight
4323324446%61%
2098
16th to endNight
2212323345%68%
2079
May1st to 15thNight
3324324446%61%
2099
16th to endNight
3213435%45%6%58%
2075
June1st to 15thNight
31134345%7%10%53%
1764
16th to endNight
4214337%6%6%10%48%
1755
July1st to 15thNight
43245%35%6%9%10%44%
1939
16th to endNight
4324426%6%7%11%46%
2051
August1st to 15thNight
3213435%7%10%16%42%
1919
16th to endNight
43245%36%7%8%13%40%
2070
September1st to 15thNight
7%424435%6%7%9%42%
1955
16th to endNight
7%5%15%435%5%7%8%43%
2145
October1st to 15thNight
5%214423447%57%
2178
16th to endNight
421331234467%
2496
November1st to 15thNight
2212213346%68%
2547
16th to endNight
3213313236%68%
2730
December1st to 15thNight
5%32442335%7%57%
2730
16th to endNight
3313324435%63%
2866

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
4424314447%57%
2090
16th to endDay
3323333445%62%
2240
February1st to 15thDay
2214334446%63%
2050
16th to endDay
2213213346%66%
1840
March1st to 15thDay
3424435%45%5%55%
2131
16th to endDay
2313324447%61%
2591
April1st to 15thDay
221342445%7%60%
2510
16th to endDay
2312312346%68%
2486
May1st to 15thDay
332332335%6%62%
2511
16th to endDay
32123245%5%7%62%
2737
June1st to 15thDay
111332447%9%59%
2549
16th to endDay
3324435%6%7%10%47%
2527
July1st to 15thDay
8%5%35%7%5%8%9%7%9%30%
2340
16th to endDay
5%435%8%5%8%7%9%9%32%
2469
August1st to 15thDay
5%415%6%5%8%8%9%12%32%
2294
16th to endDay
7%5%37%8%5%7%7%7%9%31%
2484
September1st to 15thDay
11%6%26%7%45%6%6%8%32%
2334
16th to endDay
9%6%25%5%45%5%6%7%40%
2145
October1st to 15thDay
5%31432345%7%57%
2108
16th to endDay
431332234466%
2080
November1st to 15thDay
2313223435%66%
1955
16th to endDay
3313312245%68%
1890
December1st to 15thDay
5%42342335%7%56%
1890
16th to endDay
241332445%7%60%
2072
January1st to 15thNight
34245%2435%6%57%
2508
16th to endNight
4323333347%60%
2688
February1st to 15thNight
22143245%48%61%
2462
16th to endNight
221332445%7%61%
2206
March1st to 15thNight
331442445%7%56%
2486
16th to endNight
2323423445%62%
2332
April1st to 15thNight
3213424346%61%
2098
16th to endNight
1212324345%67%
2079
May1st to 15thNight
3323424347%60%
2099
16th to endNight
3214425%46%6%57%
2075
June1st to 15thNight
22134345%8%10%53%
1764
16th to endNight
3214436%5%7%10%49%
1755
July1st to 15thNight
32145%36%6%8%10%44%
1939
16th to endNight
4324426%6%8%10%46%
2051
August1st to 15thNight
2213425%7%10%15%42%
1919
16th to endNight
4325%5%46%6%8%13%39%
2070
September1st to 15thNight
6%4145%36%6%7%10%42%
1955
16th to endNight
5%5%25%436%6%8%8%43%
2145
October1st to 15thNight
4214423448%57%
2178
16th to endNight
321232334467%
2496
November1st to 15thNight
222323346%68%
2547
16th to endNight
2313312336%67%
2730
December1st to 15thNight
43245%2435%6%57%
2730
16th to endNight
3313324335%62%
2866

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
24%46%18%29%16%
2091
16th to endDay
20%36%14%35%19%
2240
February1st to 15thDay
19%47%16%24%27%
2051
16th to endDay
17%25%14%32%27%
1840
March1st to 15thDay
25%36%15%24%23%
2131
16th to endDay
19%37%12%30%26%
2593
April1st to 15thDay
21%37%10%29%28%
2510
16th to endDay
15%25%11%33%31%
2486
May1st to 15thDay
20%46%13%26%29%
2511
16th to endDay
17%5%8%16%25%27%
2740
June1st to 15thDay
17%5%12%19%26%19%
2549
16th to endDay
26%8%11%20%19%13%
2527
July1st to 15thDay
40%11%14%20%11%1
2211
16th to endDay
37%11%17%23%9%
2326
August1st to 15thDay
34%11%18%24%9%1
2281
16th to endDay
42%10%17%18%9%1
2484
September1st to 15thDay
41%10%14%16%12%4
2334
16th to endDay
37%6%10%18%20%6%
2145
October1st to 15thDay
22%6%10%22%21%16%
2108
16th to endDay
20%25%15%29%26%
2080
November1st to 15thDay
16%48%20%28%20%
1955
16th to endDay
17%26%17%32%23%
1890
December1st to 15thDay
23%37%19%31%14%
1890
16th to endDay
20%47%20%32%15%
2072
January1st to 15thNight
25%36%15%29%19%
2508
16th to endNight
21%36%14%36%17%
2688
February1st to 15thNight
18%47%13%25%29%
2472
16th to endNight
19%46%10%29%28%
2206
March1st to 15thNight
21%48%15%25%24%
2486
16th to endNight
20%37%13%29%25%
2332
April1st to 15thNight
21%37%12%28%26%
2098
16th to endNight
17%36%15%25%31%
2079
May1st to 15thNight
21%47%14%24%27%
2100
16th to endNight
23%6%9%18%20%22%
2077
June1st to 15thNight
21%6%13%23%21%13%
1764
16th to endNight
26%6%14%18%20%13%
1755
July1st to 15thNight
27%9%19%28%13%2
1839
16th to endNight
26%10%20%28%13%1
1931
August1st to 15thNight
21%11%22%28%15%
1908
16th to endNight
30%11%18%24%12%2
2070
September1st to 15thNight
31%10%18%20%12%6%
1955
16th to endNight
33%8%13%20%17%6%
2145
October1st to 15thNight
24%6%12%22%17%16%
2178
16th to endNight
19%36%13%28%28%
2496
November1st to 15thNight
15%36%20%34%19%
2547
16th to endNight
17%25%14%33%26%
2730
December1st to 15thNight
24%36%19%28%17%
2730
16th to endNight
21%37%17%33%16%
2866

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
10%16%27%32%13%
180
16th to endDay
226%26%27%13%3
192
February1st to 15thDay
416%31%26%21%
180
16th to endDay
5%25%35%23%10%
159
March1st to 15thDay
6%12%47%25%8%
211
16th to endDay
418%44%23%7%1
416
April1st to 15thDay
5%20%41%24%8%
389
16th to endDay
422%40%27%4
378
May1st to 15thDay
419%36%30%8%
408
16th to endDay
45%36%38%12%1
568
June1st to 15thDay
2113%47%29%4
576
16th to endDay
5%9%36%39%8%
562
July1st to 15thDay
8%5%29%40%16%
365
16th to endDay
6%5%26%44%17%
391
August1st to 15thDay
5%15%24%43%19%
359
16th to endDay
11%1426%39%15%
396
September1st to 15thDay
11%18%30%35%11%
369
16th to endDay
11%216%31%26%11%
180
October1st to 15thDay
12%218%36%23%6%
180
16th to endDay
7%325%22%27%13%
192
November1st to 15thDay
7%10%25%33%15%7%
180
16th to endDay
8%13%27%25%20%5%
180
December1st to 15thDay
11%11%28%35%12%1
180
16th to endDay
6%21%37%26%8%
192
January1st to 15thNight
5%7%31%36%17%1
840
16th to endNight
5%12%26%38%15%1
896
February1st to 15thNight
410%28%37%17%1
824
16th to endNight
313%37%37%7%
736
March1st to 15thNight
5%11%29%36%15%1
840
16th to endNight
410%30%39%14%1
764
April1st to 15thNight
5%13%31%39%10%
629
16th to endNight
210%33%42%10%
624
May1st to 15thNight
5%7%33%41%11%
630
16th to endNight
4426%47%16%
659
June1st to 15thNight
318%50%26%1
588
16th to endNight
410%49%32%1
585
July1st to 15thNight
46%36%48%2
555
16th to endNight
4338%48%5%
612
August1st to 15thNight
3222%61%9%
575
16th to endNight
6%226%57%6%
621
September1st to 15thNight
8%427%51%6%
585
16th to endNight
10%8%39%36%5%
582
October1st to 15thNight
6%214%40%32%3
618
16th to endNight
6%317%33%30%8%
832
November1st to 15thNight
4322%36%28%5%
907
16th to endNight
47%21%37%25%3
1050
December1st to 15thNight
7%8%26%37%18%2
1050
16th to endNight
5%14%29%35%13%1
1074
Page generated at 2019-06-02 18:43:07. Version ac04

Copyright 2019 A. Danko


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