Rainbow Park Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Rainbow Park Observatory clear sky chart from 2005-11-06 to 2024-11-02.

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
58%
24953
29%
95117
21%
24779
68%
24779
37%
46713

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
56%
754
29%
4018
24%
736
71%
736
29%
1918
January11th to 20thNight
49%
756
40%
3941
25%
740
63%
740
35%
1468
January21st to endNight
50%
825
22%
4319
22%
814
66%
814
25%
2248
February1st to 10thNight
49%
760
32%
2470
21%
760
65%
760
46%
1171
February11th to 20thNight
42%
741
30%
2233
16%
740
57%
740
41%
1181
February21st to endNight
39%
628
37%
1884
19%
628
58%
628
48%
923
March1st to 10thNight
47%
752
41%
3367
19%
744
61%
744
38%
1357
March11th to 20thNight
49%
752
26%
3465
18%
740
59%
740
26%
1944
March21st to endNight
44%
785
23%
3581
15%
771
60%
771
35%
1444
April1st to 10thNight
43%
570
35%
1900
19%
570
63%
570
45%
872
April11th to 20thNight
40%
563
32%
1877
19%
563
60%
563
40%
915
April21st to endNight
47%
570
32%
1900
19%
570
66%
570
44%
884
May1st to 10thNight
50%
566
36%
2980
22%
559
65%
559
37%
1072
May11th to 20thNight
53%
549
20%
2891
19%
541
61%
541
25%
1351
May21st to endNight
54%
606
25%
2820
19%
593
67%
593
46%
952
June1st to 10thNight
68%
570
29%
1520
22%
570
72%
570
49%
812
June11th to 20thNight
64%
570
32%
1520
24%
570
69%
570
59%
756
June21st to endNight
68%
570
21%
1520
16%
570
70%
570
41%
902
July1st to 10thNight
73%
538
25%
2350
16%
535
75%
535
25%
1191
July11th to 20thNight
75%
538
16%
2442
15%
533
76%
533
22%
1399
July21st to endNight
74%
606
11%
2714
14%
569
75%
569
16%
1711
August1st to 10thNight
78%
553
14%
2693
15%
545
79%
545
18%
1730
August11th to 20thNight
73%
544
15%
2819
22%
543
74%
543
20%
1510
August21st to endNight
80%
608
15%
3356
27%
605
81%
605
19%
2058
September1st to 10thNight
78%
570
30%
1900
32%
570
79%
570
35%
1048
September11th to 20thNight
77%
570
35%
1900
35%
570
80%
570
43%
950
September21st to endNight
75%
673
34%
2137
28%
673
80%
673
52%
1001
October1st to 10thNight
63%
760
32%
2280
23%
760
70%
760
45%
1200
October11th to 20thNight
66%
760
38%
2280
25%
760
76%
760
58%
1039
October21st to endNight
64%
836
41%
2508
24%
836
76%
836
56%
1165
November1st to 10thNight
70%
748
44%
2244
30%
748
80%
748
65%
966
November11th to 20thNight
66%
912
38%
2432
24%
912
73%
912
63%
1166
November21st to endNight
56%
950
36%
2470
21%
950
65%
950
48%
1350
December1st to 10thNight
54%
950
35%
2656
21%
950
64%
950
52%
1353
December11th to 20thNight
51%
948
29%
3128
17%
948
61%
948
39%
1631
December21st to endNight
45%
1002
20%
4602
18%
993
56%
993
31%
2075

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
331433436%8%62%
100797
Night
442444435%7%58%
98409
TransparencyDay
18%6%10%22%27%18%
100560
Night
22%7%10%20%25%16%
98235
SeeingDay
5%8%20%30%26%11%
14978
Night
6%5%24%42%21%2
25142

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
36%34224446%61%
2858
11th to 20thDay
231323335%6%69%
2860
21st to endDay
46%26%44435%7%55%
3146
February1st to 10thDay
36%2433236%6%62%
1710
11th to 20thDay
45%25%43325%7%61%
1833
21st to endDay
35%14423347%64%
1570
March1st to 10thDay
2313333346%67%
3384
11th to 20thDay
9%5%25%444447%51%
3490
21st to endDay
35%25%33335%7%60%
3901
April1st to 10thDay
331333335%7%67%
2280
11th to 20thDay
2414333345%67%
2251
21st to endDay
231323345%6%68%
2280
May1st to 10thDay
211222435%6%72%
3800
11th to 20thDay
331444447%9%57%
3942
21st to endDay
2111222245%78%
4720
June1st to 10thDay
221233437%9%64%
2660
11th to 20thDay
21223335%6%73%
2660
21st to endDay
431434446%8%59%
2660
July1st to 10thDay
221334447%8%62%
4175
11th to 20thDay
1213235%6%10%13%55%
4110
21st to endDay
2314446%6%11%12%45%
4454
August1st to 10thDay
2213346%5%10%13%50%
4041
11th to 20thDay
221333446%11%62%
3726
21st to endDay
3315%45%6%5%8%12%47%
4180
September1st to 10thDay
442434446%7%58%
2280
11th to 20thDay
4214335%36%6%62%
2280
21st to endDay
3212323345%71%
2037
October1st to 10thDay
6%21423335%6%64%
1900
11th to 20thDay
321322223475%
1900
21st to endDay
421222222477%
2090
November1st to 10thDay
2212233346%74%
1869
11th to 20thDay
2212223246%73%
1727
21st to endDay
5%424333245%66%
1710
December1st to 10thDay
45%23333336%66%
1520
11th to 20thDay
4325%34446%8%57%
1926
21st to endDay
45%24333247%63%
2867
January1st to 10thNight
37%35%43435%5%58%
4097
11th to 20thNight
4313222345%70%
4110
21st to endNight
6%8%25%43335%8%53%
4521
February1st to 10thNight
26%24323247%65%
2470
11th to 20thNight
6%5%25%333346%60%
2233
21st to endNight
35%24223345%67%
1884
March1st to 10thNight
4414333245%67%
3473
11th to 20thNight
13%7%35%434346%48%
3490
21st to endNight
341433435%6%64%
3747
April1st to 10thNight
441433335%7%64%
1900
11th to 20thNight
45%25%333345%63%
1877
21st to endNight
5%313333346%65%
1900
May1st to 10thNight
4324333345%66%
3170
11th to 20thNight
5%5%26%5%4446%7%51%
2958
21st to endNight
3213342335%71%
2863
June1st to 10thNight
32143345%6%11%58%
1520
11th to 20thNight
331432335%6%68%
1520
21st to endNight
4425%45%5%5%8%10%48%
1520
July1st to 10thNight
2224446%5%8%8%55%
2788
11th to 20thNight
2327%6%6%8%6%11%12%38%
2860
21st to endNight
5%6%26%6%7%8%6%9%11%34%
3109
August1st to 10thNight
2339%8%8%10%6%10%12%30%
2894
11th to 20thNight
3326%6%5%6%6%9%12%43%
3113
21st to endNight
3427%7%8%8%6%11%12%32%
3487
September1st to 10thNight
5%315%5%5%5%5%7%9%50%
1900
11th to 20thNight
5%413435%45%6%59%
1900
21st to endNight
4314333345%67%
2137
October1st to 10thNight
7%32433335%5%62%
2280
11th to 20thNight
421322233474%
2280
21st to endNight
431322223474%
2508
November1st to 10thNight
2213212235%77%
2244
11th to 20thNight
2312222246%75%
2432
21st to endNight
5%5%14332235%66%
2470
December1st to 10thNight
4414222346%67%
2656
11th to 20thNight
5%42334446%8%58%
3271
21st to endNight
5%6%25%333235%63%
4827

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
21%7%10%35%23%4
2859
11th to 20thDay
14%7%16%37%23%3
2860
21st to endDay
28%7%10%26%24%5%
3146
February1st to 10thDay
21%5%11%25%26%11%
1710
11th to 20thDay
23%49%25%28%11%
1843
21st to endDay
21%36%19%31%19%
1570
March1st to 10thDay
15%6%6%19%35%19%
3384
11th to 20thDay
22%14%12%21%23%9%
3490
21st to endDay
20%6%7%20%34%12%
3901
April1st to 10thDay
16%47%17%35%22%
2280
11th to 20thDay
18%48%16%29%25%
2254
21st to endDay
16%48%19%33%20%
2280
May1st to 10thDay
9%38%16%34%30%
3800
11th to 20thDay
16%8%10%20%29%16%
3945
21st to endDay
8%36%11%22%50%
4720
June1st to 10thDay
13%6%10%20%25%28%
2660
11th to 20thDay
11%5%5%11%22%46%
2660
21st to endDay
20%5%10%19%20%25%
2660
July1st to 10thDay
17%7%11%13%21%31%
4111
11th to 20thDay
15%8%16%31%23%8%
4041
21st to endDay
23%10%17%31%17%2
4314
August1st to 10thDay
19%9%20%26%18%8%
4027
11th to 20thDay
15%7%12%23%27%17%
3762
21st to endDay
25%9%18%23%19%6%
4179
September1st to 10thDay
23%8%11%19%25%15%
2280
11th to 20thDay
19%7%11%16%25%21%
2280
21st to endDay
14%5%7%20%32%22%
2037
October1st to 10thDay
20%7%8%19%24%22%
1900
11th to 20thDay
14%3413%36%30%
1900
21st to endDay
13%38%20%38%18%
2090
November1st to 10thDay
12%36%22%39%18%
1869
11th to 20thDay
13%5%8%24%38%12%
1727
21st to endDay
22%36%24%33%13%
1710
December1st to 10thDay
21%48%33%23%10%
1520
11th to 20thDay
23%8%13%27%23%6%
1924
21st to endDay
21%5%10%22%30%13%
2867
January1st to 10thNight
25%7%11%27%24%5%
4097
11th to 20thNight
17%6%9%35%27%6%
4110
21st to endNight
28%9%10%24%24%5%
4521
February1st to 10thNight
20%410%24%30%11%
2470
11th to 20thNight
25%5%8%21%27%13%
2233
21st to endNight
19%46%17%33%20%
1884
March1st to 10thNight
18%5%6%17%37%17%
3473
11th to 20thNight
30%11%10%17%23%10%
3490
21st to endNight
17%7%10%22%32%12%
3747
April1st to 10thNight
19%47%16%31%23%
1900
11th to 20thNight
22%46%13%26%28%
1877
21st to endNight
18%6%10%15%31%20%
1900
May1st to 10thNight
15%5%9%12%29%29%
3170
11th to 20thNight
23%11%14%17%19%17%
2959
21st to endNight
12%6%6%10%17%50%
2863
June1st to 10thNight
17%9%13%16%18%26%
1520
11th to 20thNight
15%5%7%10%21%43%
1520
21st to endNight
26%9%14%12%14%25%
1520
July1st to 10thNight
22%10%11%14%13%29%
2743
11th to 20thNight
27%11%18%27%12%5%
2806
21st to endNight
35%12%17%25%9%1
3011
August1st to 10thNight
35%14%16%18%10%6%
2885
11th to 20thNight
28%10%15%16%16%15%
3143
21st to endNight
36%11%18%18%12%5%
3487
September1st to 10thNight
27%9%13%18%20%14%
1900
11th to 20thNight
22%6%12%16%21%23%
1900
21st to endNight
17%5%7%16%28%26%
2137
October1st to 10thNight
23%6%9%15%23%25%
2280
11th to 20thNight
15%35%12%31%34%
2280
21st to endNight
16%35%17%38%21%
2508
November1st to 10thNight
11%3421%40%20%
2244
11th to 20thNight
13%46%20%40%17%
2432
21st to endNight
22%46%19%33%16%
2470
December1st to 10thNight
19%49%28%31%8%
2656
11th to 20thNight
22%7%11%26%26%8%
3272
21st to endNight
24%5%8%22%31%10%
4827

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
5%5%29%44%16%1
270
11th to 20thDay
7%9%26%35%18%4
270
21st to endDay
18%33%34%19%4
297
February1st to 10thDay
5%10%36%31%17%2
270
11th to 20thDay
9%7%33%41%9%1
270
21st to endDay
8%14%40%28%10%
225
March1st to 10thDay
6%18%29%30%15%2
422
11th to 20thDay
10%14%28%31%13%3
460
21st to endDay
10%20%34%23%10%2
506
April1st to 10thDay
7%16%33%29%12%3
460
11th to 20thDay
7%17%36%27%12%1
452
21st to endDay
6%16%33%28%13%3
460
May1st to 10thDay
5%13%31%31%17%3
463
11th to 20thDay
5%10%25%28%23%9%
488
21st to endDay
49%25%37%21%4
668
June1st to 10thDay
2415%35%35%9%
680
11th to 20thDay
2417%37%31%9%
680
21st to endDay
5%411%32%39%9%
680
July1st to 10thDay
238%28%42%17%
525
11th to 20thDay
32418%39%35%
484
21st to endDay
32216%39%37%
531
August1st to 10thDay
325%18%46%26%
487
11th to 20thDay
326%23%40%26%
477
21st to endDay
426%26%38%25%
539
September1st to 10thDay
5%27%26%37%23%
490
11th to 20thDay
3115%33%34%14%
490
21st to endDay
5%5%15%22%36%18%
354
October1st to 10thDay
5%5%19%23%35%13%
300
11th to 20thDay
7%6%17%30%30%10%
300
21st to endDay
8%7%14%34%30%7%
330
November1st to 10thDay
5%11%19%41%22%3
273
11th to 20thDay
35%19%40%24%9%
270
21st to endDay
10%7%27%32%20%4
270
December1st to 10thDay
8%5%29%37%17%4
270
11th to 20thDay
6%10%25%40%17%3
270
21st to endDay
11%8%29%41%9%1
297
January1st to 10thNight
6%330%45%15%1
760
11th to 20thNight
8%5%32%39%15%1
760
21st to endNight
7%6%32%41%14%1
836
February1st to 10thNight
5%7%34%41%12%1
760
11th to 20thNight
7%8%37%40%7%
744
21st to endNight
6%8%44%38%4
628
March1st to 10thNight
7%6%35%40%11%
760
11th to 20thNight
8%6%30%43%13%
760
21st to endNight
7%11%33%40%10%
793
April1st to 10thNight
411%38%38%8%
570
11th to 20thNight
5%13%38%35%8%
563
21st to endNight
7%8%33%44%6%1
570
May1st to 10thNight
48%32%45%10%1
570
11th to 20thNight
8%5%24%44%17%1
561
21st to endNight
4332%46%15%
617
June1st to 10thNight
3417%53%22%1
570
11th to 20thNight
35%23%46%23%1
570
21st to endNight
4216%49%29%
570
July1st to 10thNight
329%45%38%3
555
11th to 20thNight
335%33%51%4
552
21st to endNight
42428%53%9%
624
August1st to 10thNight
426%26%54%8%
567
11th to 20thNight
6%25%40%43%4
564
21st to endNight
42337%49%5%
627
September1st to 10thNight
5%26%45%40%2
570
11th to 20thNight
5%28%49%34%2
570
21st to endNight
5%412%48%29%1
673
October1st to 10thNight
7%5%19%45%23%2
760
11th to 20thNight
5%320%50%20%2
760
21st to endNight
6%422%44%21%3
836
November1st to 10thNight
3222%51%20%1
748
11th to 20thNight
3424%48%17%3
912
21st to endNight
8%8%24%37%22%2
950
December1st to 10thNight
6%431%44%14%1
950
11th to 20thNight
9%6%29%44%11%1
950
21st to endNight
8%6%33%42%10%
1012
Page generated at 2024-10-30 11:19:24. Version ac07

Copyright © 2024 Attilla Danko.


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