Chimney Rock
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chimney Rock clear sky chart from 2005-11-06 to 2024-01-14.

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
60%
24319
28%
74541
22%
24269
66%
24269
38%
41144

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%
803
27%
2500
21%
799
65%
799
39%
1344
January11th to 20thNight
54%
736
30%
2391
26%
736
63%
736
38%
1275
January21st to endNight
57%
792
30%
2574
27%
792
65%
792
37%
1399
February1st to 10thNight
52%
720
28%
2340
23%
720
62%
720
40%
1221
February11th to 20thNight
48%
703
27%
2191
20%
700
57%
700
33%
1263
February21st to endNight
44%
592
31%
1776
21%
592
56%
592
37%
1017
March1st to 10thNight
52%
720
28%
1998
19%
720
59%
720
40%
1149
March11th to 20thNight
55%
720
28%
1980
20%
720
59%
720
40%
1153
March21st to endNight
49%
771
28%
2157
16%
771
59%
771
36%
1279
April1st to 10thNight
46%
540
27%
1800
20%
540
58%
540
34%
958
April11th to 20thNight
49%
533
27%
1777
21%
533
60%
533
32%
960
April21st to endNight
50%
540
30%
1800
22%
540
63%
540
35%
965
May1st to 10thNight
54%
540
28%
1737
24%
540
62%
540
38%
906
May11th to 20thNight
58%
531
23%
1586
19%
531
62%
531
34%
934
May21st to endNight
59%
583
29%
1552
19%
582
65%
582
41%
878
June1st to 10thNight
71%
540
31%
1440
24%
540
75%
540
53%
766
June11th to 20thNight
71%
540
32%
1440
26%
540
74%
540
57%
724
June21st to endNight
76%
540
29%
1440
24%
540
78%
540
51%
769
July1st to 10thNight
72%
525
17%
1434
14%
525
73%
525
34%
887
July11th to 20thNight
74%
522
19%
1566
16%
522
75%
522
33%
939
July21st to endNight
71%
591
11%
1674
10%
558
72%
558
23%
1143
August1st to 10thNight
74%
537
17%
1602
17%
534
75%
534
31%
974
August11th to 20thNight
72%
534
23%
1713
24%
534
74%
534
31%
990
August21st to endNight
74%
594
22%
1980
25%
594
76%
594
31%
1157
September1st to 10thNight
72%
540
25%
1800
28%
540
74%
540
32%
1012
September11th to 20thNight
70%
540
35%
1800
35%
540
74%
540
37%
962
September21st to endNight
72%
691
32%
2049
26%
691
75%
691
48%
1063
October1st to 10thNight
63%
720
29%
2160
23%
720
67%
720
39%
1204
October11th to 20thNight
72%
720
38%
2160
28%
720
79%
720
56%
1001
October21st to endNight
69%
792
39%
2376
28%
792
77%
792
51%
1163
November1st to 10thNight
71%
740
39%
2220
30%
740
76%
740
55%
1047
November11th to 20thNight
66%
949
39%
2469
24%
949
74%
949
61%
1231
November21st to endNight
58%
950
32%
2607
21%
950
64%
950
42%
1475
December1st to 10thNight
54%
950
27%
2660
18%
950
61%
950
42%
1492
December11th to 20thNight
51%
948
25%
3127
17%
948
56%
948
29%
1873
December21st to endNight
45%
1032
14%
4665
15%
1026
50%
1026
21%
2571

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
5%5%244345%5%7%54%
74679
Night
6%6%2442445%6%56%
75096
TransparencyDay
27%6%9%22%25%11%
74401
Night
28%5%9%22%24%11%
74895
SeeingDay
10%11%28%30%17%4
14066
Night
10%419%44%22%2
24336

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
5%10%2342346%7%54%
1680
11th to 20thDay
7%10%24322345%58%
1647
21st to endDay
7%9%36%424445%54%
1782
February1st to 10thDay
49%345%32446%56%
1620
11th to 20thDay
6%10%37%4245%5%6%48%
1656
21st to endDay
6%12%46%5%34346%46%
1480
March1st to 10thDay
7%8%35%5%3345%8%49%
1960
11th to 20thDay
5%9%345%3446%7%50%
1980
21st to endDay
6%7%36%6%3445%8%48%
2197
April1st to 10thDay
6%5%24435%5%6%7%54%
2160
11th to 20thDay
46%245%35%5%6%8%52%
2131
21st to endDay
5%425%5%35%5%6%7%54%
2160
May1st to 10thDay
6%425%435%5%5%8%54%
2220
11th to 20thDay
6%6%245%35%6%7%7%49%
2305
21st to endDay
5%32343445%6%60%
2724
June1st to 10thDay
42123245%6%8%63%
2520
11th to 20thDay
321232335%6%71%
2520
21st to endDay
2213436%5%7%8%60%
2520
July1st to 10thDay
3225%6%46%7%6%9%50%
2480
11th to 20thDay
33245%46%7%9%11%46%
2340
21st to endDay
6%425%7%6%8%9%10%11%34%
2545
August1st to 10thDay
6%426%7%46%6%8%8%42%
2328
11th to 20thDay
5%425%5%47%7%7%8%45%
2185
21st to endDay
7%3245%46%7%7%10%46%
2376
September1st to 10thDay
8%4244346%6%7%51%
2160
11th to 20thDay
8%3135%245%5%7%56%
2160
21st to endDay
9%313323335%65%
1905
October1st to 10thDay
9%32442445%5%57%
1800
11th to 20thDay
6%31222332472%
1800
21st to endDay
6%423323335%67%
1980
November1st to 10thDay
5%312213345%70%
1840
11th to 20thDay
4313222346%69%
1710
21st to endDay
7%6%23423346%61%
1568
December1st to 10thDay
7%8%3331245%7%57%
1520
11th to 20thDay
7%9%45%4345%5%7%48%
1926
21st to endDay
5%11%36%42435%5%52%
2794
January1st to 10thNight
5%9%24324446%58%
2500
11th to 20thNight
6%8%3432333460%
2391
21st to endNight
7%8%3432335%6%57%
2574
February1st to 10thNight
6%9%24312335%61%
2340
11th to 20thNight
8%10%25%423446%54%
2190
21st to endNight
7%12%3442333456%
1776
March1st to 10thNight
7%7%24425%435%57%
1998
11th to 20thNight
6%9%35%42345%6%54%
1980
21st to endNight
8%7%345%33345%55%
2157
April1st to 10thNight
7%7%24435%45%6%55%
1800
11th to 20thNight
8%425%5%35%5%45%54%
1777
21st to endNight
7%6%24434445%58%
1800
May1st to 10thNight
6%5%244345%47%57%
1737
11th to 20thNight
9%5%25%5%345%5%7%51%
1586
21st to endNight
8%41443445%6%58%
1552
June1st to 10thNight
32134245%47%66%
1440
11th to 20thNight
3313323346%69%
1440
21st to endNight
3212435%5%7%8%59%
1440
July1st to 10thNight
3425%6%5%7%7%8%8%45%
1476
11th to 20thNight
4425%6%46%6%8%11%45%
1620
21st to endNight
7%5%26%6%5%7%9%10%11%32%
1773
August1st to 10thNight
45%26%6%46%6%7%10%44%
1611
11th to 20thNight
5%435%6%46%5%8%10%44%
1713
21st to endNight
5%325%6%46%7%8%10%43%
1980
September1st to 10thNight
6%326%6%35%6%8%9%46%
1800
11th to 20thNight
7%325%5%3445%7%56%
1800
21st to endNight
8%313323345%64%
2049
October1st to 10thNight
12%423323445%58%
2160
11th to 20thNight
5%213222335%72%
2160
21st to endNight
6%313322345%68%
2376
November1st to 10thNight
5%412213346%68%
2220
11th to 20thNight
3312212335%74%
2469
21st to endNight
9%8%2331333460%
2607
December1st to 10thNight
7%8%25%423336%58%
2660
11th to 20thNight
7%9%35%5%2445%6%49%
3271
21st to endNight
7%10%47%5%3334451%
4873

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
29%417%31%16%3
1681
11th to 20thDay
29%411%32%22%2
1647
21st to endDay
33%5%11%31%16%4
1782
February1st to 10thDay
30%5%15%26%20%4
1620
11th to 20thDay
37%48%27%21%3
1665
21st to endDay
39%47%17%27%5%
1480
March1st to 10thDay
34%47%24%25%6%
1960
11th to 20thDay
33%5%7%26%25%5%
1980
21st to endDay
34%6%7%24%24%5%
2197
April1st to 10thDay
28%5%8%23%25%12%
2160
11th to 20thDay
28%5%6%22%26%12%
2134
21st to endDay
27%6%7%23%29%8%
2160
May1st to 10thDay
26%5%8%21%31%8%
2220
11th to 20thDay
31%7%9%22%23%8%
2308
21st to endDay
23%5%7%16%32%17%
2724
June1st to 10thDay
17%6%7%21%28%21%
2520
11th to 20thDay
13%45%13%28%36%
2520
21st to endDay
18%6%7%16%26%27%
2520
July1st to 10thDay
27%9%12%16%16%21%
2413
11th to 20thDay
25%11%16%22%17%9%
2271
21st to endDay
35%13%22%19%9%2
2404
August1st to 10thDay
34%10%12%16%15%13%
2313
11th to 20thDay
30%10%11%18%19%12%
2185
21st to endDay
28%9%11%21%22%8%
2376
September1st to 10thDay
29%7%10%17%23%14%
2160
11th to 20thDay
24%8%8%17%25%17%
2160
21st to endDay
22%4418%37%13%
1905
October1st to 10thDay
28%6%7%21%24%14%
1800
11th to 20thDay
18%3419%40%16%
1800
21st to endDay
22%27%27%34%8%
1980
November1st to 10thDay
17%37%31%34%7%
1840
11th to 20thDay
17%38%33%35%5%
1710
21st to endDay
27%35%31%25%9%
1568
December1st to 10thDay
28%416%27%19%7%
1520
11th to 20thDay
36%7%9%28%18%3
1924
21st to endDay
32%5%11%18%27%7%
2794
January1st to 10thNight
29%412%32%21%3
2500
11th to 20thNight
29%311%31%22%3
2391
21st to endNight
29%5%8%36%17%5%
2574
February1st to 10thNight
28%313%30%19%7%
2340
11th to 20thNight
34%48%25%23%5%
2191
21st to endNight
33%38%19%31%6%
1776
March1st to 10thNight
29%47%23%28%8%
1998
11th to 20thNight
31%36%28%22%9%
1980
21st to endNight
32%46%23%27%6%
2157
April1st to 10thNight
31%37%18%27%13%
1800
11th to 20thNight
30%5%6%18%27%14%
1777
21st to endNight
29%45%21%30%11%
1800
May1st to 10thNight
26%5%6%20%31%11%
1737
11th to 20thNight
32%6%11%18%23%9%
1587
21st to endNight
25%6%9%15%27%18%
1552
June1st to 10thNight
19%5%8%18%24%25%
1440
11th to 20thNight
17%35%13%20%42%
1440
21st to endNight
19%6%9%14%23%28%
1440
July1st to 10thNight
32%8%15%13%10%22%
1434
11th to 20thNight
30%10%14%20%11%15%
1566
21st to endNight
38%15%23%14%8%3
1674
August1st to 10thNight
31%11%16%14%13%14%
1602
11th to 20thNight
32%7%15%17%17%12%
1713
21st to endNight
31%9%15%20%16%9%
1980
September1st to 10thNight
31%7%13%17%16%16%
1800
11th to 20thNight
28%6%9%15%21%22%
1800
21st to endNight
22%5%5%16%36%16%
2049
October1st to 10thNight
29%5%7%16%24%19%
2160
11th to 20thNight
17%35%18%39%19%
2160
21st to endNight
20%36%25%34%13%
2376
November1st to 10thNight
18%36%29%35%9%
2220
11th to 20thNight
15%37%33%35%7%
2469
21st to endNight
30%25%26%30%7%
2607
December1st to 10thNight
29%213%28%22%5%
2660
11th to 20thNight
35%5%11%26%21%3
3272
21st to endNight
36%5%9%20%25%5%
4873

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
19%5%31%28%15%3
270
11th to 20thDay
21%6%31%31%9%2
249
21st to endDay
8%8%34%39%9%3
264
February1st to 10thDay
8%11%35%37%8%2
240
11th to 20thDay
18%13%34%28%6%1
240
21st to endDay
18%20%33%22%7%1
198
March1st to 10thDay
16%21%28%25%10%
400
11th to 20thDay
17%18%32%22%9%3
420
21st to endDay
18%27%31%19%4
462
April1st to 10thDay
11%26%36%20%7%
420
11th to 20thDay
17%31%30%16%6%
412
21st to endDay
13%28%35%16%6%1
420
May1st to 10thDay
12%22%41%18%7%1
423
11th to 20thDay
11%15%35%26%12%2
452
21st to endDay
9%14%30%30%16%1
679
June1st to 10thDay
5%7%24%37%23%4
630
11th to 20thDay
49%31%31%20%4
630
21st to endDay
310%27%32%24%5%
630
July1st to 10thDay
3418%36%32%6%
583
11th to 20thDay
4318%35%28%12%
444
21st to endDay
7%211%36%34%9%
487
August1st to 10thDay
6%6%16%38%26%7%
447
11th to 20thDay
5%422%38%24%7%
437
21st to endDay
7%322%36%26%6%
495
September1st to 10thDay
7%324%34%24%8%
450
11th to 20thDay
5%5%27%40%20%3
450
21st to endDay
11%7%25%33%19%6%
350
October1st to 10thDay
12%9%21%29%22%7%
270
11th to 20thDay
10%11%26%30%19%6%
270
21st to endDay
12%10%26%30%20%3
297
November1st to 10thDay
9%13%28%31%17%2
270
11th to 20thDay
48%34%32%18%4
270
21st to endDay
15%5%31%26%20%3
270
December1st to 10thDay
14%9%30%32%10%5%
270
11th to 20thDay
11%8%30%35%13%2
270
21st to endDay
19%10%29%31%10%1
297
January1st to 10thNight
12%324%43%16%3
803
11th to 20thNight
10%324%45%15%3
736
21st to endNight
12%322%46%14%3
792
February1st to 10thNight
12%227%46%12%2
720
11th to 20thNight
13%428%43%12%1
704
21st to endNight
15%331%44%7%
592
March1st to 10thNight
10%6%27%45%12%
720
11th to 20thNight
10%5%22%44%18%1
720
21st to endNight
11%9%23%44%12%1
771
April1st to 10thNight
11%8%30%44%8%
540
11th to 20thNight
12%9%23%43%13%
533
21st to endNight
10%10%25%41%14%
540
May1st to 10thNight
8%6%26%45%16%
540
11th to 20thNight
10%221%45%20%1
531
21st to endNight
10%7%18%43%20%2
584
June1st to 10thNight
5%316%48%28%1
540
11th to 20thNight
4317%50%25%1
540
21st to endNight
4112%49%33%1
540
July1st to 10thNight
328%47%39%1
525
11th to 20thNight
426%36%44%8%
522
21st to endNight
7%25%30%47%9%
591
August1st to 10thNight
5%15%32%50%6%
537
11th to 20thNight
6%26%39%42%4
534
21st to endNight
6%25%40%43%5%
594
September1st to 10thNight
8%16%44%38%4
540
11th to 20thNight
8%210%46%32%2
540
21st to endNight
9%211%44%31%3
691
October1st to 10thNight
13%314%46%23%2
720
11th to 20thNight
7%214%52%23%3
720
21st to endNight
8%316%48%20%5%
792
November1st to 10thNight
7%215%52%21%3
740
11th to 20thNight
5%421%47%19%3
949
21st to endNight
14%419%37%22%3
950
December1st to 10thNight
12%5%23%45%13%2
950
11th to 20thNight
14%5%21%44%14%1
950
21st to endNight
14%5%24%45%11%1
1045
Page generated at 2024-01-11 11:32:01. Version ac07

Copyright 2024 Attilla Danko


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