Cherry Road
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cherry Road clear sky chart from 2005-11-06 to 2024-01-13.

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%
24059
35%
74322
30%
24012
78%
24012
52%
35237

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
65%
760
34%
2457
30%
756
75%
756
45%
1187
January11th to 20thNight
65%
728
36%
2366
34%
728
72%
728
45%
1161
January21st to endNight
59%
792
36%
2574
32%
792
68%
792
40%
1337
February1st to 10thNight
64%
720
36%
2277
30%
720
77%
720
51%
1051
February11th to 20thNight
59%
700
34%
2099
28%
700
71%
700
47%
1067
February21st to endNight
60%
592
36%
1776
33%
592
67%
592
46%
911
March1st to 10thNight
58%
720
36%
1989
27%
720
68%
720
50%
1024
March11th to 20thNight
63%
720
36%
1980
27%
720
71%
720
51%
1031
March21st to endNight
62%
792
36%
2178
24%
792
72%
792
55%
1072
April1st to 10thNight
64%
720
33%
1980
20%
720
74%
720
59%
950
April11th to 20thNight
59%
607
38%
1828
25%
607
72%
607
57%
804
April21st to endNight
63%
540
45%
1620
31%
540
76%
540
70%
663
May1st to 10thNight
69%
540
39%
1620
29%
540
76%
540
61%
698
May11th to 20thNight
71%
531
40%
1594
32%
531
76%
531
66%
669
May21st to endNight
71%
582
39%
1746
30%
582
76%
582
74%
694
June1st to 10thNight
81%
540
36%
1620
31%
540
83%
540
72%
653
June11th to 20thNight
79%
540
37%
1620
31%
540
82%
540
76%
630
June21st to endNight
82%
540
33%
1620
31%
540
84%
540
64%
696
July1st to 10thNight
86%
525
27%
1575
24%
525
86%
525
51%
770
July11th to 20thNight
88%
522
25%
1566
22%
522
88%
522
50%
785
July21st to endNight
79%
591
23%
1674
19%
558
80%
558
35%
958
August1st to 10thNight
87%
537
27%
1602
23%
534
87%
534
48%
808
August11th to 20thNight
87%
534
31%
1602
28%
534
87%
534
48%
803
August21st to endNight
87%
692
33%
1970
29%
692
87%
692
49%
1050
September1st to 10thNight
82%
720
31%
1980
28%
720
83%
720
51%
1042
September11th to 20thNight
86%
720
42%
1980
35%
720
88%
720
67%
907
September21st to endNight
79%
720
40%
1980
30%
720
85%
720
64%
918
October1st to 10thNight
74%
720
38%
2009
28%
720
80%
720
57%
981
October11th to 20thNight
82%
720
43%
2160
38%
720
86%
720
70%
893
October21st to endNight
75%
792
45%
2376
36%
792
84%
792
68%
985
November1st to 10thNight
77%
740
41%
2231
37%
740
83%
740
61%
998
November11th to 20thNight
75%
760
41%
2470
38%
760
82%
760
62%
1025
November21st to endNight
68%
760
39%
2470
35%
760
76%
760
50%
1131
December1st to 10thNight
68%
760
36%
2470
35%
760
74%
760
47%
1183
December11th to 20thNight
65%
758
33%
2932
32%
758
72%
758
33%
1561
December21st to endNight
61%
824
22%
4331
30%
817
68%
817
24%
2141

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
431332445%6%64%
74942
Night
3313323446%67%
74827
TransparencyDay
20%36%15%28%29%
74669
Night
19%35%15%28%30%
74622
SeeingDay
6%10%24%31%21%8%
13838
Night
5%315%39%33%5%
24079

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
6%423423246%62%
1708
11th to 20thDay
5%42332335%5%66%
1638
21st to endDay
6%7%14333447%58%
1782
February1st to 10thDay
342432335%6%65%
1678
11th to 20thDay
5%5%345%23346%59%
1750
21st to endDay
5%6%25%333446%60%
1480
March1st to 10thDay
44244345%5%7%59%
1970
11th to 20thDay
5%423423346%63%
1980
21st to endDay
3324324446%64%
2178
April1st to 10thDay
2213333338%68%
1980
11th to 20thDay
2213223335%73%
2075
21st to endDay
2312223346%72%
2340
May1st to 10thDay
2213323346%70%
2340
11th to 20thDay
2213324346%72%
2301
21st to endDay
1223212335%76%
2530
June1st to 10thDay
1112213335%78%
2340
11th to 20thDay
111111123485%
2340
21st to endDay
1212313345%75%
2340
July1st to 10thDay
1213336%6%7%7%60%
2340
11th to 20thDay
43246%47%8%8%10%44%
2340
21st to endDay
5%435%8%5%7%8%10%11%34%
2545
August1st to 10thDay
4325%5%35%6%6%9%52%
2328
11th to 20thDay
33145%46%6%8%10%49%
2299
21st to endDay
5%324435%6%8%9%52%
2381
September1st to 10thDay
43245%345%6%7%56%
1980
11th to 20thDay
3112222445%75%
1980
21st to endDay
3312323245%73%
1980
October1st to 10thDay
3313323445%69%
1949
11th to 20thDay
222212225%81%
1800
21st to endDay
121222223478%
1980
November1st to 10thDay
121222345%6%73%
1845
11th to 20thDay
2213213345%74%
1710
21st to endDay
6%314322335%68%
1710
December1st to 10thDay
7%423424436%62%
1710
11th to 20thDay
6%5%25%6%3446%8%51%
2169
21st to endDay
9%6%26%5%23446%54%
3146
January1st to 10thNight
5%31342345%6%62%
2457
11th to 20thNight
6%423323445%64%
2366
21st to endNight
6%6%24423345%60%
2574
February1st to 10thNight
3313323335%70%
2277
11th to 20thNight
5%41432445%6%62%
2098
21st to endNight
6%5%22323446%63%
1776
March1st to 10thNight
342432336%8%62%
1989
11th to 20thNight
6%413412346%65%
1980
21st to endNight
331332335%7%67%
2178
April1st to 10thNight
3112323447%69%
1980
11th to 20thNight
2212222336%73%
1828
21st to endNight
1111222246%78%
1620
May1st to 10thNight
2212313345%74%
1620
11th to 20thNight
221231223478%
1594
21st to endNight
12221122483%
1746
June1st to 10thNight
1111212245%79%
1620
11th to 20thNight
111121212385%
1620
21st to endNight
221321233478%
1620
July1st to 10thNight
2234346%5%8%62%
1620
11th to 20thNight
12133246%9%10%57%
1620
21st to endNight
3425%6%46%7%8%12%43%
1773
August1st to 10thNight
1313335%5%6%10%60%
1611
11th to 20thNight
3213336%6%8%10%55%
1602
21st to endNight
32133346%6%9%59%
1970
September1st to 10thNight
23244245%7%9%58%
1980
11th to 20thNight
3212212345%76%
1980
21st to endNight
212323236%76%
1980
October1st to 10thNight
3213323446%70%
2009
11th to 20thNight
311221222481%
2160
21st to endNight
111221224480%
2376
November1st to 10thNight
2212212445%74%
2231
11th to 20thNight
2212322345%75%
2470
21st to endNight
6%312223336%68%
2470
December1st to 10thNight
6%412323447%64%
2470
11th to 20thNight
6%425%43445%7%54%
3041
21st to endNight
8%4145%345%45%57%
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
25%25%18%32%17%
1709
11th to 20thDay
23%4418%33%18%
1638
21st to endDay
26%26%18%32%16%
1782
February1st to 10thDay
22%26%15%28%26%
1678
11th to 20thDay
28%3317%26%23%
1760
21st to endDay
24%35%16%30%22%
1480
March1st to 10thDay
24%3317%30%23%
1970
11th to 20thDay
23%2416%33%21%
1980
21st to endDay
20%35%17%39%17%
2178
April1st to 10thDay
17%2417%35%26%
1980
11th to 20thDay
15%2312%33%35%
2078
21st to endDay
14%2412%36%33%
2340
May1st to 10thDay
14%2413%33%33%
2340
11th to 20thDay
13%25%13%32%35%
2304
21st to endDay
11%1311%31%42%
2530
June1st to 10thDay
9%227%33%48%
2340
11th to 20thDay
6%11321%68%
2340
21st to endDay
12%235%22%55%
2340
July1st to 10thDay
18%5%7%14%19%38%
2276
11th to 20thDay
29%8%13%19%19%12%
2271
21st to endDay
33%7%18%20%14%8%
2404
August1st to 10thDay
25%5%10%17%18%25%
2313
11th to 20thDay
24%5%12%22%19%18%
2299
21st to endDay
25%6%9%17%27%16%
2381
September1st to 10thDay
24%48%14%24%27%
1980
11th to 20thDay
11%2413%33%36%
1980
21st to endDay
14%3310%32%38%
1980
October1st to 10thDay
17%35%17%23%35%
1949
11th to 20thDay
9%1310%32%45%
1800
21st to endDay
11%2414%33%36%
1980
November1st to 10thDay
13%2319%36%27%
1845
11th to 20thDay
13%1417%31%33%
1710
21st to endDay
21%2316%32%26%
1710
December1st to 10thDay
26%36%18%24%23%
1710
11th to 20thDay
32%49%19%21%15%
2168
21st to endDay
32%35%20%29%10%
3146
January1st to 10thNight
23%35%22%33%15%
2457
11th to 20thNight
24%2318%32%20%
2366
21st to endNight
28%25%14%31%19%
2574
February1st to 10thNight
19%25%16%30%28%
2277
11th to 20thNight
23%25%18%27%24%
2099
21st to endNight
24%25%12%34%23%
1776
March1st to 10thNight
21%3416%31%25%
1989
11th to 20thNight
22%3216%31%26%
1980
21st to endNight
18%37%16%36%21%
2178
April1st to 10thNight
16%3414%35%28%
1980
11th to 20thNight
15%1310%34%37%
1828
21st to endNight
10%2411%37%37%
1620
May1st to 10thNight
14%25%12%29%39%
1620
11th to 20thNight
12%2410%31%41%
1595
21st to endNight
9%1310%32%46%
1746
June1st to 10thNight
9%215%26%57%
1620
11th to 20thNight
7%12317%70%
1620
21st to endNight
13%215%17%61%
1620
July1st to 10thNight
19%5%7%11%18%40%
1575
11th to 20thNight
18%6%16%20%24%16%
1566
21st to endNight
30%7%16%21%15%11%
1674
August1st to 10thNight
19%7%11%16%19%28%
1602
11th to 20thNight
21%5%15%21%18%21%
1602
21st to endNight
21%6%8%21%26%18%
1970
September1st to 10thNight
21%5%11%17%20%26%
1980
11th to 20thNight
12%3413%30%38%
1980
21st to endNight
12%4310%30%42%
1980
October1st to 10thNight
18%2416%23%36%
2009
11th to 20thNight
11%139%26%49%
2160
21st to endNight
10%25%11%29%43%
2376
November1st to 10thNight
15%2315%36%29%
2231
11th to 20thNight
13%3415%30%35%
2470
21st to endNight
19%3314%32%29%
2470
December1st to 10thNight
22%36%19%25%26%
2470
11th to 20thNight
30%46%17%27%16%
3041
21st to endNight
30%6%5%19%27%13%
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
15%8%25%30%22%
270
11th to 20thDay
14%425%34%21%2
246
21st to endDay
6%11%23%33%22%5%
264
February1st to 10thDay
6%11%26%36%14%7%
298
11th to 20thDay
13%17%31%27%13%
415
21st to endDay
14%22%29%24%10%1
346
March1st to 10thDay
9%22%28%28%10%3
420
11th to 20thDay
10%16%30%23%18%4
420
21st to endDay
9%23%34%21%11%2
462
April1st to 10thDay
6%18%33%24%12%6%
420
11th to 20thDay
9%22%35%21%10%3
412
21st to endDay
6%20%34%23%12%6%
420
May1st to 10thDay
5%19%33%26%13%4
423
11th to 20thDay
314%32%30%17%5%
448
21st to endDay
6%14%35%26%15%5%
485
June1st to 10thDay
110%30%34%18%7%
450
11th to 20thDay
311%30%33%16%8%
450
21st to endDay
2425%40%22%7%
450
July1st to 10thDay
1220%38%29%11%
446
11th to 20thDay
5%110%36%32%16%
444
21st to endDay
426%32%36%21%
487
August1st to 10thDay
2214%37%30%15%
447
11th to 20thDay
3212%35%34%14%
437
21st to endDay
5%110%33%30%21%
495
September1st to 10thDay
5%218%33%30%12%
450
11th to 20thDay
3424%34%29%7%
450
21st to endDay
6%8%20%35%21%9%
450
October1st to 10thDay
5%12%26%26%22%10%
419
11th to 20thDay
45%18%31%31%11%
270
21st to endDay
410%16%28%32%9%
297
November1st to 10thDay
7%7%18%35%27%7%
270
11th to 20thDay
6%6%16%33%29%10%
270
21st to endDay
10%8%21%34%21%6%
270
December1st to 10thDay
10%7%19%33%28%3
270
11th to 20thDay
28%25%40%21%4
270
21st to endDay
18%11%19%32%18%3
297
January1st to 10thNight
7%318%45%21%5%
760
11th to 20thNight
7%5%18%42%24%4
728
21st to endNight
8%5%20%43%22%2
792
February1st to 10thNight
5%422%41%25%2
720
11th to 20thNight
7%5%24%44%19%1
704
21st to endNight
10%6%21%44%17%2
592
March1st to 10thNight
6%6%26%44%17%1
720
11th to 20thNight
8%420%37%27%3
720
21st to endNight
46%23%43%22%2
792
April1st to 10thNight
45%23%46%21%2
720
11th to 20thNight
410%24%39%22%1
607
21st to endNight
15%28%39%23%4
540
May1st to 10thNight
25%19%45%28%1
540
11th to 20thNight
2318%41%34%2
531
21st to endNight
3220%43%28%4
584
June1st to 10thNight
2212%47%36%2
540
11th to 20thNight
1216%46%33%3
540
21st to endNight
2110%35%48%4
540
July1st to 10thNight
2432%55%6%
525
11th to 20thNight
2220%60%17%
522
21st to endNight
32217%60%16%
591
August1st to 10thNight
3220%63%12%
537
11th to 20thNight
31221%63%10%
534
21st to endNight
31217%60%17%
692
September1st to 10thNight
315%27%52%12%
720
11th to 20thNight
216%35%50%7%
720
21st to endNight
2113%36%42%6%
720
October1st to 10thNight
4313%42%35%3
720
11th to 20thNight
3210%47%34%4
720
21st to endNight
3415%36%34%8%
792
November1st to 10thNight
3213%45%31%4
740
11th to 20thNight
2316%44%31%5%
760
21st to endNight
7%319%40%28%3
760
December1st to 10thNight
8%417%41%29%1
760
11th to 20thNight
11%315%46%24%1
760
21st to endNight
10%419%46%18%3
836
Page generated at 2024-01-09 23:25:04. Version ac07

Copyright 2024 Attilla Danko


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