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 2018-02-22.

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%
16270
33%
48930
21%
16227
68%
16227
48%
24266

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%
778
33%
2522
22%
776
65%
776
48%
1189
January16th to endNight
45%
832
38%
2704
24%
832
65%
832
49%
1246
February1st to 15thNight
49%
763
34%
2360
21%
760
65%
760
52%
1088
February16th to endNight
36%
660
39%
1978
16%
660
59%
660
47%
953
March1st to 15thNight
47%
720
36%
2034
19%
720
61%
720
49%
1006
March16th to endNight
47%
717
38%
2061
19%
717
63%
717
53%
980
April1st to 15thNight
38%
539
35%
1798
15%
539
62%
539
46%
800
April16th to endNight
38%
540
40%
1800
20%
540
67%
540
53%
747
May1st to 15thNight
45%
540
28%
1799
19%
539
61%
539
46%
835
May16th to endNight
57%
562
32%
1663
20%
561
70%
561
51%
812
June1st to 15thNight
61%
540
29%
1440
20%
540
67%
540
54%
753
June16th to endNight
72%
540
24%
1440
20%
540
74%
540
47%
799
July1st to 15thNight
75%
510
20%
1503
19%
510
75%
510
36%
876
July16th to endNight
81%
564
20%
1593
19%
531
81%
531
36%
918
August1st to 15thNight
82%
539
18%
1755
20%
536
82%
536
31%
1037
August16th to endNight
81%
573
25%
1910
28%
573
82%
573
35%
1051
September1st to 15thNight
71%
540
26%
1800
27%
540
74%
540
32%
1042
September16th to endNight
72%
546
37%
1921
32%
546
81%
546
46%
889
October1st to 15thNight
63%
720
34%
2160
23%
720
71%
720
51%
1050
October16th to endNight
65%
768
41%
2304
25%
768
76%
768
61%
1015
November1st to 15thNight
58%
813
39%
2333
21%
813
70%
813
64%
1028
November16th to endNight
57%
975
39%
2535
22%
975
66%
975
54%
1301
December1st to 15thNight
49%
975
35%
2629
18%
975
62%
975
52%
1345
December16th to endNight
43%
1016
33%
2888
19%
1016
55%
1016
46%
1506

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%62%
49302
Night
321232345%7%63%
49127
TransparencyDay
21%5%9%18%27%18%
48998
Night
19%5%9%19%28%17%
48933
SeeingDay
6%10%23%31%22%6%
5904
Night
46%27%36%22%2
16274

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
2312222347%67%
1746
16th to endDay
4311212345%68%
1872
February1st to 15thDay
2312122245%71%
1832
16th to endDay
2412323337%67%
1642
March1st to 15thDay
2213424347%62%
1923
16th to endDay
221331335%6%67%
2162
April1st to 15thDay
2212213347%66%
2150
16th to endDay
22121233475%
2160
May1st to 15thDay
2112324446%64%
2151
16th to endDay
212213447%69%
2444
June1st to 15thDay
122235%5%8%68%
2520
16th to endDay
321222446%8%61%
2520
July1st to 15thDay
7%4245%347%7%9%43%
2363
16th to endDay
43246%47%7%9%11%36%
2467
August1st to 15thDay
5%3246%46%7%8%11%40%
2194
16th to endDay
5%325%6%36%5%7%10%44%
2292
September1st to 15thDay
7%5%25%435%5%6%7%46%
2160
16th to endDay
5%213322345%64%
2034
October1st to 15thDay
331322223469%
1800
16th to endDay
21221222476%
1920
November1st to 15thDay
121212235%74%
1841
16th to endDay
331321222471%
1755
December1st to 15thDay
3312112336%68%
1657
16th to endDay
4412323436%63%
1697
January1st to 15thNight
3312213346%67%
2522
16th to endNight
3212113246%69%
2704
February1st to 15thNight
2412212347%68%
2350
16th to endNight
321321345%6%65%
1978
March1st to 15thNight
221232335%7%65%
2034
16th to endNight
3212213335%71%
2061
April1st to 15thNight
3212213248%66%
1798
16th to endNight
2212212335%73%
1800
May1st to 15thNight
2213324346%64%
1799
16th to endNight
3112213448%66%
1663
June1st to 15thNight
12242445%8%62%
1440
16th to endNight
223325%6%7%9%55%
1440
July1st to 15thNight
43235%26%6%7%10%45%
1593
16th to endNight
3214336%6%8%14%45%
1701
August1st to 15thNight
4213435%8%10%12%42%
1764
16th to endNight
2222435%6%9%12%47%
1910
September1st to 15thNight
6%324435%6%7%9%46%
1800
16th to endNight
321332335%6%65%
1921
October1st to 15thNight
3212213346%68%
2160
16th to endNight
21221223376%
2304
November1st to 15thNight
111112246%74%
2333
16th to endNight
331222322471%
2535
December1st to 15thNight
432212336%67%
2629
16th to endNight
441222335%7%62%
2888

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
17%38%20%38%11%
1747
16th to endDay
18%36%18%36%16%
1872
February1st to 15thDay
15%27%20%32%20%
1833
16th to endDay
17%25%17%38%17%
1642
March1st to 15thDay
20%36%17%32%19%
1923
16th to endDay
17%25%16%35%22%
2162
April1st to 15thDay
17%36%16%33%22%
2150
16th to endDay
13%25%14%34%29%
2160
May1st to 15thDay
18%49%14%28%23%
2151
16th to endDay
15%5%6%16%25%30%
2447
June1st to 15thDay
13%49%16%23%33%
2520
16th to endDay
18%5%11%16%21%26%
2520
July1st to 15thDay
33%9%14%16%12%13%
2224
16th to endDay
33%13%19%20%11%1
2312
August1st to 15thDay
32%11%17%22%12%3
2179
16th to endDay
33%9%14%20%15%6%
2292
September1st to 15thDay
34%7%13%18%17%8%
2160
16th to endDay
21%5%8%18%26%19%
2034
October1st to 15thDay
19%37%15%30%23%
1800
16th to endDay
14%25%19%36%22%
1920
November1st to 15thDay
12%27%21%36%18%
1841
16th to endDay
18%1419%35%20%
1755
December1st to 15thDay
17%38%29%29%10%
1657
16th to endDay
22%5%11%24%29%6%
1697
January1st to 15thNight
18%49%18%37%11%
2522
16th to endNight
17%46%17%40%13%
2704
February1st to 15thNight
17%27%22%30%19%
2360
16th to endNight
18%35%18%36%18%
1978
March1st to 15thNight
17%36%19%33%18%
2034
16th to endNight
16%25%16%36%21%
2061
April1st to 15thNight
17%36%17%33%21%
1798
16th to endNight
13%35%15%34%28%
1800
May1st to 15thNight
19%39%13%30%24%
1800
16th to endNight
16%6%8%16%24%28%
1665
June1st to 15thNight
18%5%9%15%16%34%
1440
16th to endNight
21%7%12%15%14%28%
1440
July1st to 15thNight
27%8%14%22%14%11%
1503
16th to endNight
25%10%23%25%12%1
1593
August1st to 15thNight
28%11%21%20%13%3
1755
16th to endNight
23%11%15%28%14%5%
1910
September1st to 15thNight
30%8%15%20%14%10%
1800
16th to endNight
19%48%19%27%20%
1921
October1st to 15thNight
17%5%8%16%28%23%
2160
16th to endNight
12%35%17%33%27%
2304
November1st to 15thNight
11%26%20%36%21%
2333
16th to endNight
18%25%16%35%21%
2535
December1st to 15thNight
18%38%25%29%13%
2629
16th to endNight
21%410%25%29%8%
2888

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
9%13%34%28%11%2
135
16th to endDay
419%30%25%17%2
144
February1st to 15thDay
313%29%32%20%
135
16th to endDay
11%22%32%25%10%
100
March1st to 15thDay
6%19%33%28%10%1
213
16th to endDay
7%21%37%22%6%3
288
April1st to 15thDay
9%28%30%23%6%1
269
16th to endDay
9%25%41%18%32
270
May1st to 15thDay
422%38%25%6%2
288
16th to endDay
211%38%30%16%
426
June1st to 15thDay
2420%37%30%4
495
16th to endDay
2213%34%39%7%
495
July1st to 15thDay
6%7%38%37%9%
328
16th to endDay
6%425%36%26%
327
August1st to 15thDay
5%18%33%34%16%
315
16th to endDay
7%9%38%32%12%
332
September1st to 15thDay
8%212%40%27%8%
315
16th to endDay
5%5%20%39%26%
201
October1st to 15thDay
8%6%21%40%18%4
135
16th to endDay
5%424%31%21%12%
144
November1st to 15thDay
8%13%33%22%17%5%
135
16th to endDay
7%20%32%24%14%1
135
December1st to 15thDay
414%31%34%13%2
135
16th to endDay
11%18%31%33%4
144
January1st to 15thNight
46%34%37%14%3
780
16th to endNight
49%36%31%16%1
832
February1st to 15thNight
47%35%37%12%1
764
16th to endNight
413%44%33%5%
660
March1st to 15thNight
213%34%34%13%
720
16th to endNight
211%36%37%11%
717
April1st to 15thNight
415%40%31%7%
539
16th to endNight
412%42%34%6%
540
May1st to 15thNight
37%40%39%9%
540
16th to endNight
2431%45%15%
563
June1st to 15thNight
2227%46%21%
540
16th to endNight
2117%45%30%2
540
July1st to 15thNight
47%37%46%3
510
16th to endNight
3423%59%9%
564
August1st to 15thNight
4423%56%10%
539
16th to endNight
25%28%55%7%
573
September1st to 15thNight
6%12%35%41%2
540
16th to endNight
4215%45%27%4
546
October1st to 15thNight
3423%43%21%2
720
16th to endNight
25%23%37%25%5%
768
November1st to 15thNight
2431%37%21%2
813
16th to endNight
5%8%25%34%21%3
975
December1st to 15thNight
6%7%33%36%14%1
975
16th to endNight
8%10%35%35%9%
1016
Page generated at 2018-02-23 09:21:41. Version ac04

Copyright 2018 A. Danko


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