This page made possible by the sponsorship of: Robert & Elaine White.

Majestic Skies Ranch
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Majestic Skies Ranch clear sky chart from 2005-11-05 to 2019-09-17.

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
56%
18228
33%
54857
21%
18185
68%
18185
47%
27322

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%
838
33%
2717
22%
836
65%
836
46%
1297
January16th to endNight
45%
896
37%
2912
23%
896
64%
896
50%
1328
February1st to 15thNight
48%
823
36%
2545
22%
820
65%
820
51%
1183
February16th to endNight
36%
736
37%
2206
16%
736
58%
736
49%
1055
March1st to 15thNight
44%
840
37%
2374
18%
840
61%
840
49%
1174
March16th to endNight
47%
837
37%
2405
18%
837
64%
837
53%
1138
April1st to 15thNight
38%
629
37%
2098
16%
629
63%
629
46%
933
April16th to endNight
39%
624
37%
2079
19%
624
66%
624
50%
889
May1st to 15thNight
47%
630
29%
2099
21%
629
62%
629
47%
973
May16th to endNight
55%
658
32%
1949
20%
657
69%
657
53%
932
June1st to 15thNight
61%
630
30%
1680
21%
630
68%
630
53%
880
June16th to endNight
72%
630
25%
1680
20%
630
74%
630
48%
917
July1st to 15thNight
74%
600
20%
1768
19%
600
74%
600
36%
1042
July16th to endNight
80%
660
19%
1881
18%
627
80%
627
35%
1094
August1st to 15thNight
82%
620
18%
2018
21%
617
82%
617
32%
1181
August16th to endNight
82%
669
23%
2230
26%
669
83%
669
36%
1220
September1st to 15thNight
71%
630
27%
2100
29%
630
74%
630
32%
1207
September16th to endNight
73%
595
35%
2092
31%
595
81%
595
46%
967
October1st to 15thNight
62%
780
34%
2340
23%
780
70%
780
48%
1160
October16th to endNight
64%
832
39%
2496
23%
832
74%
832
57%
1137
November1st to 15thNight
58%
877
41%
2517
22%
877
70%
877
64%
1113
November16th to endNight
57%
1050
38%
2730
21%
1050
66%
1050
55%
1391
December1st to 15thNight
49%
1050
36%
2831
19%
1050
62%
1050
51%
1461
December16th to endNight
42%
1094
31%
3110
18%
1094
54%
1094
44%
1650

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
321332345%7%61%
55813
Night
321232345%7%63%
55054
TransparencyDay
21%5%9%19%27%17%
55509
Night
19%5%9%19%28%17%
54860
SeeingDay
6%10%24%30%21%6%
8067
Night
46%27%36%22%2
18232

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
3313222347%65%
1881
16th to endDay
4312212345%68%
2016
February1st to 15thDay
2312122246%69%
1977
16th to endDay
2411223337%67%
1840
March1st to 15thDay
2213424348%61%
2243
16th to endDay
211331335%7%67%
2522
April1st to 15thDay
2212213347%66%
2510
16th to endDay
221212335%74%
2486
May1st to 15thDay
2112323446%66%
2511
16th to endDay
112212447%70%
2861
June1st to 15thDay
122235%5%8%66%
2940
16th to endDay
321222345%8%63%
2940
July1st to 15thDay
6%3246%35%7%7%9%42%
2757
16th to endDay
33246%47%7%9%11%37%
2883
August1st to 15thDay
43246%46%7%8%11%40%
2514
16th to endDay
4225%6%36%6%7%10%44%
2676
September1st to 15thDay
6%5%25%4345%6%7%47%
2520
16th to endDay
5%313322345%64%
2217
October1st to 15thDay
432322224467%
1950
16th to endDay
31221222474%
2080
November1st to 15thDay
122212235%74%
1986
16th to endDay
3313213225%70%
1890
December1st to 15thDay
3412222336%67%
1785
16th to endDay
45%13323436%61%
1828
January1st to 15thNight
3312213346%65%
2717
16th to endNight
3212113346%69%
2912
February1st to 15thNight
2412212347%68%
2535
16th to endNight
3213213347%66%
2206
March1st to 15thNight
221232335%7%65%
2374
16th to endNight
2212213346%70%
2405
April1st to 15thNight
3212223348%66%
2098
16th to endNight
2212212346%70%
2079
May1st to 15thNight
221332445%7%64%
2099
16th to endNight
2112213347%68%
1949
June1st to 15thNight
12232445%8%61%
1680
16th to endNight
213325%6%7%8%57%
1680
July1st to 15thNight
43235%26%7%7%11%44%
1858
16th to endNight
2214436%6%7%14%44%
1989
August1st to 15thNight
3213435%8%10%12%42%
2027
16th to endNight
2222445%6%9%12%46%
2230
September1st to 15thNight
5%324435%6%6%9%47%
2100
16th to endNight
321332335%6%65%
2092
October1st to 15thNight
3212323346%67%
2340
16th to endNight
321221223474%
2496
November1st to 15thNight
111112246%74%
2517
16th to endNight
331222322471%
2730
December1st to 15thNight
432212346%65%
2831
16th to endNight
45%12213347%61%
3110

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
18%48%19%36%11%
1882
16th to endDay
18%36%19%36%15%
2016
February1st to 15thDay
16%38%20%30%20%
1978
16th to endDay
17%25%16%39%18%
1840
March1st to 15thDay
21%36%19%30%19%
2243
16th to endDay
17%26%18%34%20%
2522
April1st to 15thDay
17%36%17%33%22%
2510
16th to endDay
13%35%15%34%27%
2486
May1st to 15thDay
18%49%15%30%22%
2511
16th to endDay
14%5%6%17%25%31%
2864
June1st to 15thDay
14%49%16%24%30%
2940
16th to endDay
17%5%10%15%23%27%
2940
July1st to 15thDay
33%10%14%16%12%12%
2618
16th to endDay
31%13%20%21%11%1
2728
August1st to 15thDay
32%11%18%22%11%3
2499
16th to endDay
31%10%15%20%15%6%
2676
September1st to 15thDay
32%7%13%19%19%8%
2520
16th to endDay
22%5%7%18%26%18%
2217
October1st to 15thDay
20%38%15%29%21%
1950
16th to endDay
15%35%20%33%20%
2080
November1st to 15thDay
12%27%23%36%17%
1986
16th to endDay
18%1419%35%19%
1890
December1st to 15thDay
19%38%28%29%10%
1785
16th to endDay
23%411%23%29%7%
1828
January1st to 15thNight
19%49%18%35%11%
2717
16th to endNight
16%46%18%41%12%
2912
February1st to 15thNight
17%27%22%29%19%
2545
16th to endNight
17%35%18%35%19%
2206
March1st to 15thNight
18%36%19%32%19%
2374
16th to endNight
16%37%18%35%20%
2405
April1st to 15thNight
17%26%18%33%21%
2098
16th to endNight
14%36%16%32%25%
2079
May1st to 15thNight
19%39%13%30%22%
2100
16th to endNight
15%5%7%16%23%30%
1951
June1st to 15thNight
18%5%9%17%17%32%
1680
16th to endNight
20%7%11%14%15%30%
1680
July1st to 15thNight
28%8%14%22%14%11%
1768
16th to endNight
25%11%23%25%11%1
1881
August1st to 15thNight
27%12%22%22%12%3
2018
16th to endNight
23%11%16%27%15%6%
2230
September1st to 15thNight
30%8%16%19%15%9%
2100
16th to endNight
19%48%19%27%19%
2092
October1st to 15thNight
18%5%8%16%28%22%
2340
16th to endNight
14%36%17%32%25%
2496
November1st to 15thNight
11%26%22%36%20%
2517
16th to endNight
17%26%16%35%21%
2730
December1st to 15thNight
19%38%24%29%13%
2831
16th to endNight
23%49%24%29%8%
3110

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
12%10%33%31%11%2
180
16th to endDay
5%17%33%28%14%1
192
February1st to 15thDay
420%31%27%17%
180
16th to endDay
10%27%33%22%6%
159
March1st to 15thDay
8%18%36%26%8%
323
16th to endDay
6%21%39%22%8%2
416
April1st to 15thDay
10%23%32%23%8%1
389
16th to endDay
8%21%39%20%6%2
378
May1st to 15thDay
319%36%26%10%3
408
16th to endDay
312%38%30%14%
570
June1st to 15thDay
2322%38%28%3
645
16th to endDay
3214%35%37%7%
645
July1st to 15thDay
6%7%36%37%11%
452
16th to endDay
5%423%38%27%
455
August1st to 15thDay
5%7%33%34%18%
419
16th to endDay
5%8%36%34%14%
460
September1st to 15thDay
8%211%34%29%12%
435
16th to endDay
7%419%35%28%4
257
October1st to 15thDay
10%9%25%36%15%3
180
16th to endDay
7%6%22%31%19%11%
192
November1st to 15thDay
6%15%35%22%14%6%
180
16th to endDay
5%17%32%23%18%1
180
December1st to 15thDay
5%14%30%37%10%1
180
16th to endDay
13%16%32%34%3
192
January1st to 15thNight
46%33%37%14%3
840
16th to endNight
49%37%32%15%1
896
February1st to 15thNight
5%8%35%37%11%1
824
16th to endNight
412%44%33%4
736
March1st to 15thNight
313%36%33%12%
840
16th to endNight
211%37%36%12%
837
April1st to 15thNight
414%40%32%7%
629
16th to endNight
411%42%34%6%
624
May1st to 15thNight
36%38%39%11%
630
16th to endNight
25%33%44%14%
659
June1st to 15thNight
2227%46%20%
630
16th to endNight
2117%46%29%1
630
July1st to 15thNight
47%37%45%4
600
16th to endNight
35%22%59%8%
660
August1st to 15thNight
4425%55%9%
620
16th to endNight
25%30%54%6%
669
September1st to 15thNight
6%11%36%41%2
630
16th to endNight
4214%45%28%3
595
October1st to 15thNight
4423%43%20%2
780
16th to endNight
45%22%37%25%4
832
November1st to 15thNight
25%31%38%20%2
877
16th to endNight
5%8%25%35%21%3
1050
December1st to 15thNight
7%7%32%37%14%
1050
16th to endNight
8%9%35%35%9%
1094
Page generated at 2019-09-17 19:12:15. Version ac04

Copyright 2019 A. Danko


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