Rustic Valley Observator
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rustic Valley Observator clear sky chart from 2005-11-06 to 2024-01-12.

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
72%
24772
40%
74390
31%
24727
81%
24727
66%
31366

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
67%
758
36%
2457
30%
756
77%
756
54%
1074
January11th to 20thNight
69%
728
39%
2355
34%
728
80%
728
56%
1024
January21st to endNight
59%
792
42%
2376
29%
792
76%
792
52%
1121
February1st to 10thNight
64%
720
40%
2160
31%
720
78%
720
57%
991
February11th to 20thNight
59%
700
41%
2098
32%
700
75%
700
58%
934
February21st to endNight
55%
592
39%
1776
31%
592
70%
592
59%
783
March1st to 10thNight
55%
720
34%
2160
25%
720
72%
720
56%
969
March11th to 20thNight
62%
720
39%
2031
28%
720
76%
720
67%
884
March21st to endNight
57%
792
39%
2137
21%
792
73%
792
63%
975
April1st to 10thNight
55%
720
39%
1800
18%
720
69%
720
64%
883
April11th to 20thNight
56%
711
43%
1779
18%
711
70%
711
72%
814
April21st to endNight
60%
708
44%
1788
19%
708
73%
708
81%
771
May1st to 10thNight
63%
540
46%
1620
27%
540
74%
540
82%
585
May11th to 20thNight
68%
531
44%
1595
27%
531
77%
531
80%
596
May21st to endNight
64%
582
42%
1746
26%
582
74%
582
80%
633
June1st to 10thNight
75%
540
39%
1620
30%
540
79%
540
80%
607
June11th to 20thNight
72%
540
41%
1620
30%
540
79%
540
86%
589
June21st to endNight
79%
540
38%
1620
30%
540
84%
540
79%
624
July1st to 10thNight
90%
525
37%
1575
31%
525
92%
525
80%
602
July11th to 20thNight
89%
522
37%
1566
31%
522
90%
522
71%
644
July21st to endNight
90%
591
37%
1674
30%
558
91%
558
58%
767
August1st to 10thNight
89%
702
38%
1767
23%
699
90%
699
80%
790
August11th to 20thNight
93%
712
42%
1780
28%
712
93%
712
79%
813
August21st to endNight
91%
792
44%
1980
31%
792
91%
792
77%
918
September1st to 10thNight
89%
720
42%
1854
32%
720
91%
720
75%
843
September11th to 20thNight
89%
720
48%
1980
41%
720
94%
720
88%
779
September21st to endNight
84%
720
47%
1980
39%
720
91%
720
84%
790
October1st to 10thNight
74%
720
45%
1980
34%
720
84%
720
76%
836
October11th to 20thNight
80%
720
51%
1980
42%
720
88%
720
82%
802
October21st to endNight
76%
792
46%
2469
41%
792
87%
792
78%
906
November1st to 10thNight
76%
740
42%
2405
38%
740
87%
740
74%
892
November11th to 20thNight
78%
760
42%
2470
40%
760
88%
760
68%
959
November21st to endNight
68%
760
41%
2470
37%
760
78%
760
59%
1036
December1st to 10thNight
68%
760
38%
2470
34%
760
78%
760
53%
1110
December11th to 20thNight
64%
759
37%
2897
31%
758
76%
758
45%
1285
December21st to endNight
58%
823
24%
4355
30%
817
70%
817
34%
1737

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
2111212335%78%
74856
Night
1111212335%78%
74906
TransparencyDay
10%35%12%24%45%
74583
Night
10%36%14%25%42%
74701
SeeingDay
28%22%37%23%7%
14415
Night
2420%37%31%6%
24794

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
3213323347%69%
1708
11th to 20thDay
4312213248%71%
1641
21st to endDay
321231345%6%70%
1980
February1st to 10thDay
3212223337%73%
1800
11th to 20thDay
2112213348%73%
1750
21st to endDay
221221335%7%72%
1480
March1st to 10thDay
2212124349%71%
1800
11th to 20thDay
2212213348%72%
1927
21st to endDay
111113345%79%
2215
April1st to 10thDay
2212223246%75%
2160
11th to 20thDay
1111111225%84%
2129
21st to endDay
111111126%85%
2168
May1st to 10thDay
11112236%83%
2340
11th to 20thDay
111122389%
2301
21st to endDay
11123488%
2530
June1st to 10thDay
11111122487%
2340
11th to 20thDay
11112292%
2340
21st to endDay
21111212286%
2340
July1st to 10thDay
212112335%79%
2340
11th to 20thDay
221122235%5%76%
2340
21st to endDay
321333445%9%64%
2545
August1st to 10thDay
211223345%78%
2159
11th to 20thDay
211113346%78%
2122
21st to endDay
2212212335%78%
2376
September1st to 10thDay
211221344476%
2105
11th to 20thDay
111112390%
1980
21st to endDay
11111222485%
1980
October1st to 10thDay
111122246%80%
1980
11th to 20thDay
11132389%
1980
21st to endDay
1121223384%
1881
November1st to 10thDay
111221212482%
1674
11th to 20thDay
211111334478%
1710
21st to endDay
11222335%6%74%
1710
December1st to 10thDay
331231346%9%65%
1710
11th to 20thDay
43132345%6%9%60%
2169
21st to endDay
6%31333446%7%61%
3146
January1st to 10thNight
221232345%6%69%
2457
11th to 20thNight
221232345%5%72%
2355
21st to endNight
3312323345%70%
2376
February1st to 10thNight
121232325%5%73%
2160
11th to 20thNight
3212212446%73%
2098
21st to endNight
121232336%8%71%
1776
March1st to 10thNight
11123235%5%8%69%
2160
11th to 20thNight
111212447%75%
2031
21st to endNight
1111212347%76%
2137
April1st to 10thNight
221122225%5%76%
1800
11th to 20thNight
121121212385%
1779
21st to endNight
11111225%86%
1788
May1st to 10thNight
11125%89%
1620
11th to 20thNight
11122389%
1594
21st to endNight
11111391%
1746
June1st to 10thNight
111112389%
1620
11th to 20thNight
111112292%
1620
21st to endNight
11111122388%
1620
July1st to 10thNight
1111123386%
1620
11th to 20thNight
1111222335%80%
1620
21st to endNight
121222345%7%69%
1773
August1st to 10thNight
1111112235%83%
1776
11th to 20thNight
11111232483%
1780
21st to endNight
21111222483%
1980
September1st to 10thNight
12111223482%
1854
11th to 20thNight
1111111292%
1980
21st to endNight
11122390%
1980
October1st to 10thNight
1111212235%82%
1980
11th to 20thNight
1111112389%
1980
21st to endNight
1111123486%
2469
November1st to 10thNight
11111223484%
2405
11th to 20thNight
111221223382%
2470
21st to endNight
221221345%7%71%
2470
December1st to 10thNight
3213213448%69%
2470
11th to 20thNight
33133235%5%10%62%
3041
21st to endNight
421333345%7%64%
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
16%48%19%27%25%
1709
11th to 20thDay
15%46%16%31%29%
1641
21st to endDay
17%47%16%26%30%
1980
February1st to 10thDay
15%38%11%28%35%
1800
11th to 20thDay
11%26%16%30%35%
1760
21st to endDay
11%5%8%17%26%32%
1480
March1st to 10thDay
13%36%18%28%33%
1800
11th to 20thDay
11%48%15%28%34%
1927
21st to endDay
9%36%18%32%32%
2215
April1st to 10thDay
13%25%14%30%34%
2160
11th to 20thDay
6%2410%31%47%
2132
21st to endDay
5%2413%29%48%
2168
May1st to 10thDay
5%2412%30%47%
2340
11th to 20thDay
4228%29%55%
2304
21st to endDay
42411%29%51%
2530
June1st to 10thDay
5%128%24%60%
2340
11th to 20thDay
2125%16%74%
2340
21st to endDay
8%1249%77%
2340
July1st to 10thDay
9%237%14%64%
2276
11th to 20thDay
10%46%14%25%41%
2271
21st to endDay
17%6%8%17%21%31%
2404
August1st to 10thDay
10%45%8%20%53%
2144
11th to 20thDay
8%46%12%21%49%
2122
21st to endDay
10%449%22%51%
2376
September1st to 10thDay
12%35%10%15%54%
2105
11th to 20thDay
422419%70%
1980
21st to endDay
6%238%22%59%
1980
October1st to 10thDay
8%3410%23%53%
1980
11th to 20thDay
4249%22%60%
1980
21st to endDay
6%347%21%59%
1881
November1st to 10thDay
8%249%27%49%
1674
11th to 20thDay
9%35%13%25%46%
1710
21st to endDay
11%36%15%26%39%
1710
December1st to 10thDay
17%47%18%22%32%
1710
11th to 20thDay
19%6%11%23%20%20%
2168
21st to endDay
21%6%10%25%23%15%
3146
January1st to 10thNight
14%48%20%26%27%
2457
11th to 20thNight
13%5%7%16%29%29%
2355
21st to endNight
17%48%17%20%34%
2376
February1st to 10thNight
15%45%14%23%38%
2160
11th to 20thNight
13%46%16%25%36%
2099
21st to endNight
12%49%17%27%31%
1776
March1st to 10thNight
13%5%8%19%28%27%
2160
11th to 20thNight
9%48%18%31%31%
2031
21st to endNight
9%48%16%33%29%
2137
April1st to 10thNight
11%47%20%31%27%
1800
11th to 20thNight
8%2414%31%41%
1779
21st to endNight
416%13%35%41%
1788
May1st to 10thNight
22418%32%42%
1620
11th to 20thNight
425%9%34%46%
1595
21st to endNight
31313%38%41%
1746
June1st to 10thNight
42210%25%57%
1620
11th to 20thNight
3117%15%73%
1620
21st to endNight
6%2249%77%
1620
July1st to 10thNight
5%225%16%69%
1575
11th to 20thNight
8%45%13%26%45%
1566
21st to endNight
13%6%6%17%27%31%
1674
August1st to 10thNight
6%25%10%22%55%
1767
11th to 20thNight
6%3311%24%52%
1780
21st to endNight
8%239%22%56%
1980
September1st to 10thNight
8%349%20%56%
1854
11th to 20thNight
4125%18%70%
1980
21st to endNight
4127%24%61%
1980
October1st to 10thNight
7%249%30%47%
1980
11th to 20thNight
5%136%26%59%
1980
21st to endNight
435%9%19%60%
2469
November1st to 10thNight
6%249%31%47%
2405
11th to 20thNight
9%2412%26%46%
2470
21st to endNight
13%36%14%28%36%
2470
December1st to 10thNight
15%5%6%19%21%34%
2470
11th to 20thNight
17%6%10%19%27%22%
3041
21st to endNight
18%6%11%28%21%15%
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
49%26%40%18%2
270
11th to 20thDay
8%8%21%37%22%4
253
21st to endDay
413%27%39%13%3
462
February1st to 10thDay
413%27%34%18%5%
420
11th to 20thDay
418%32%33%12%
415
21st to endDay
320%35%29%12%1
346
March1st to 10thDay
419%32%34%10%1
420
11th to 20thDay
413%31%34%15%3
420
21st to endDay
220%37%30%9%2
462
April1st to 10thDay
5%14%27%30%20%4
420
11th to 20thDay
219%35%28%13%3
412
21st to endDay
215%30%28%17%7%
420
May1st to 10thDay
112%30%36%15%5%
423
11th to 20thDay
12%28%35%20%5%
448
21st to endDay
111%30%35%16%7%
485
June1st to 10thDay
27%23%36%24%9%
450
11th to 20thDay
5%22%39%25%9%
450
21st to endDay
2319%39%26%10%
450
July1st to 10thDay
19%43%32%15%
446
11th to 20thDay
117%37%37%17%
444
21st to endDay
315%37%37%17%
487
August1st to 10thDay
19%40%35%14%
447
11th to 20thDay
218%39%33%17%
437
21st to endDay
118%36%37%16%
495
September1st to 10thDay
2214%44%29%9%
450
11th to 20thDay
1316%44%30%7%
450
21st to endDay
1423%37%26%9%
450
October1st to 10thDay
17%24%40%24%4
450
11th to 20thDay
5%22%42%27%5%
450
21st to endDay
16%18%38%28%8%
336
November1st to 10thDay
9%19%37%30%5%
270
11th to 20thDay
26%19%37%31%5%
270
21st to endDay
17%29%31%27%6%
270
December1st to 10thDay
6%6%20%43%23%3
270
11th to 20thDay
35%25%34%29%4
270
21st to endDay
6%10%29%34%17%4
297
January1st to 10thNight
35%22%38%24%8%
760
11th to 20thNight
2422%39%26%7%
728
21st to endNight
46%28%38%21%4
792
February1st to 10thNight
2425%38%25%7%
720
11th to 20thNight
46%28%37%22%4
704
21st to endNight
27%34%35%18%4
592
March1st to 10thNight
28%32%38%18%2
720
11th to 20thNight
16%29%32%25%7%
720
21st to endNight
19%31%37%18%4
792
April1st to 10thNight
28%33%35%20%3
720
11th to 20thNight
29%32%35%20%4
711
21st to endNight
17%31%32%24%5%
708
May1st to 10thNight
7%29%42%19%2
540
11th to 20thNight
16%24%39%27%3
531
21st to endNight
18%26%39%24%2
584
June1st to 10thNight
418%48%27%2
540
11th to 20thNight
1124%41%31%1
540
21st to endNight
1216%42%36%3
540
July1st to 10thNight
116%40%49%4
525
11th to 20thNight
25%39%50%4
522
21st to endNight
21334%55%6%
591
August1st to 10thNight
17%37%45%9%
702
11th to 20thNight
21227%58%11%
712
21st to endNight
2423%57%13%
792
September1st to 10thNight
116%29%54%9%
720
11th to 20thNight
18%41%42%8%
720
21st to endNight
1113%35%41%9%
720
October1st to 10thNight
1221%39%34%3
720
11th to 20thNight
1315%38%36%8%
720
21st to endNight
418%34%33%11%
792
November1st to 10thNight
1219%37%32%9%
740
11th to 20thNight
2314%39%33%9%
760
21st to endNight
3323%38%27%6%
760
December1st to 10thNight
4422%38%26%6%
760
11th to 20thNight
4324%39%25%5%
760
21st to endNight
48%26%37%20%6%
836
Page generated at 2024-01-09 13:24:27. Version ac07

Copyright 2024 Attilla Danko


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