Cahas Mountain Overlook
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cahas Mountain Overlook 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
40%
24299
22%
74474
12%
24247
50%
24247
24%
46347

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
17%
759
25%
2459
6%
757
39%
757
19%
1464
January11th to 20thNight
23%
729
23%
2367
8%
729
41%
729
18%
1496
January21st to endNight
18%
792
26%
2574
8%
792
41%
792
20%
1544
February1st to 10thNight
21%
720
21%
2340
9%
720
37%
720
20%
1460
February11th to 20thNight
13%
700
19%
2221
3%
699
31%
699
13%
1444
February21st to endNight
19%
592
26%
1705
8%
592
36%
592
19%
1115
March1st to 10thNight
23%
720
26%
1980
10%
720
39%
720
25%
1216
March11th to 20thNight
23%
720
19%
1980
6%
720
36%
720
20%
1319
March21st to endNight
26%
792
19%
2178
9%
792
35%
792
21%
1450
April1st to 10thNight
26%
720
21%
1919
6%
720
38%
720
23%
1239
April11th to 20thNight
34%
711
24%
1775
8%
711
43%
711
30%
1133
April21st to endNight
35%
614
25%
1694
9%
614
45%
614
29%
1065
May1st to 10thNight
37%
540
17%
1620
7%
540
44%
540
24%
1042
May11th to 20thNight
41%
531
15%
1593
8%
531
46%
531
23%
1084
May21st to endNight
58%
582
15%
1745
10%
582
61%
582
28%
1121
June1st to 10thNight
63%
540
17%
1620
16%
540
64%
540
31%
1026
June11th to 20thNight
62%
540
16%
1620
12%
540
65%
540
31%
1002
June21st to endNight
63%
540
19%
1620
15%
540
67%
540
32%
982
July1st to 10thNight
67%
525
14%
1575
12%
525
69%
525
28%
1014
July11th to 20thNight
73%
522
16%
1566
15%
522
74%
522
35%
941
July21st to endNight
69%
591
18%
1672
13%
558
71%
558
32%
1026
August1st to 10thNight
61%
537
15%
1600
11%
534
63%
534
27%
1068
August11th to 20thNight
63%
534
21%
1598
17%
534
65%
534
28%
1027
August21st to endNight
66%
748
19%
1936
13%
748
68%
748
33%
1262
September1st to 10thNight
62%
720
23%
1836
16%
720
64%
720
33%
1213
September11th to 20thNight
59%
720
24%
1980
20%
720
62%
720
30%
1284
September21st to endNight
44%
720
20%
1980
15%
720
49%
720
24%
1362
October1st to 10thNight
48%
720
22%
2142
19%
720
55%
720
28%
1337
October11th to 20thNight
42%
720
29%
2160
20%
720
56%
720
29%
1266
October21st to endNight
42%
792
31%
2376
21%
792
56%
792
32%
1341
November1st to 10thNight
41%
740
29%
2221
17%
740
55%
740
29%
1315
November11th to 20thNight
36%
760
28%
2426
15%
760
52%
760
25%
1375
November21st to endNight
35%
760
27%
2470
15%
760
51%
760
26%
1424
December1st to 10thNight
24%
760
24%
2598
8%
760
43%
760
16%
1625
December11th to 20thNight
26%
760
27%
2934
9%
758
45%
758
17%
1719
December21st to endNight
25%
828
15%
4394
8%
817
41%
817
11%
2546

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
14%6%25%5%35%5%6%8%40%
74770
Night
14%5%25%5%345%5%7%45%
74927
TransparencyDay
42%5%11%22%16%3
74492
Night
39%5%11%24%18%4
74724
SeeingDay
21%15%23%22%14%5%
14081
Night
18%13%23%28%16%2
24313

By Month

Percentage Cloud Cover SE (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
14%7%25%5%34447%45%
1706
11th to 20thDay
16%6%36%6%35%45%6%40%
1638
21st to endDay
14%8%36%434445%45%
1782
February1st to 10thDay
12%8%36%6%46%5%5%6%39%
1620
11th to 20thDay
17%6%35%6%35%446%40%
1623
21st to endDay
18%6%36%5%4435%7%39%
1549
March1st to 10thDay
13%42442445%7%49%
1980
11th to 20thDay
17%8%35%5%35%45%8%38%
1980
21st to endDay
17%7%36%6%35%5%5%6%38%
2178
April1st to 10thDay
10%5%24435%5%5%7%48%
2039
11th to 20thDay
14%5%245%35%45%8%44%
2134
21st to endDay
17%6%26%5%35%46%6%40%
2280
May1st to 10thDay
15%7%25%5%46%5%6%8%36%
2340
11th to 20thDay
17%6%37%6%35%5%6%8%33%
2301
21st to endDay
15%5%25%6%46%6%6%9%35%
2531
June1st to 10thDay
12%425%5%47%6%8%9%39%
2340
11th to 20thDay
10%425%6%46%7%7%11%37%
2340
21st to endDay
10%336%5%46%8%7%9%38%
2340
July1st to 10thDay
10%5%36%8%47%6%8%10%34%
2340
11th to 20thDay
7%425%6%5%8%8%8%11%35%
2340
21st to endDay
11%5%37%7%5%7%6%8%10%30%
2547
August1st to 10thDay
14%5%26%7%46%6%9%9%31%
2327
11th to 20thDay
14%5%36%7%47%7%8%8%30%
2303
21st to endDay
12%6%26%5%46%6%7%9%36%
2400
September1st to 10thDay
15%5%25%425%5%6%7%43%
2120
11th to 20thDay
17%6%346%4446%8%38%
1980
21st to endDay
24%6%25%425%45%6%36%
1980
October1st to 10thDay
18%5%24423446%49%
1816
11th to 20thDay
15%6%2332445%6%50%
1800
21st to endDay
14%5%25%434347%50%
1980
November1st to 10thDay
12%424424446%54%
1857
11th to 20thDay
15%5%24333447%50%
1752
21st to endDay
14%425%5%24447%49%
1710
December1st to 10thDay
13%8%26%6%46%45%7%38%
1540
11th to 20thDay
14%424324448%51%
2153
21st to endDay
19%7%25%5%35%5%6%8%35%
3124
January1st to 10thNight
13%5%344345%5%6%47%
2459
11th to 20thNight
15%7%25%5%35%45%7%42%
2367
21st to endNight
14%7%245%2445%6%46%
2574
February1st to 10thNight
14%8%25%4345%5%7%44%
2340
11th to 20thNight
19%7%35%5%3445%5%41%
2221
21st to endNight
15%5%35%6%35%45%7%43%
1705
March1st to 10thNight
13%4244245%5%6%51%
1980
11th to 20thNight
18%5%344346%6%7%39%
1980
21st to endNight
16%5%245%35%5%46%44%
2178
April1st to 10thNight
13%7%345%3345%7%45%
1919
11th to 20thNight
14%6%24433447%49%
1775
21st to endNight
16%4335%245%5%6%48%
1694
May1st to 10thNight
13%6%35%5%346%5%7%42%
1620
11th to 20thNight
16%8%36%5%3446%7%38%
1592
21st to endNight
16%424435%5%6%10%41%
1744
June1st to 10thNight
11%4145%36%6%8%11%42%
1620
11th to 20thNight
11%5%245%245%7%9%46%
1620
21st to endNight
8%325%5%35%5%7%13%44%
1620
July1st to 10thNight
10%5%25%5%36%6%7%9%41%
1620
11th to 20thNight
6%324446%6%8%12%45%
1620
21st to endNight
6%425%5%47%6%9%12%41%
1771
August1st to 10thNight
14%5%26%6%35%5%6%10%38%
1611
11th to 20thNight
12%425%5%35%6%7%9%42%
1598
21st to endNight
11%425%5%46%6%6%10%43%
1936
September1st to 10thNight
13%5%35%43445%7%47%
1836
11th to 20thNight
16%5%25%43445%7%45%
1980
21st to endNight
21%7%25%5%33445%41%
1980
October1st to 10thNight
18%5%24434347%47%
2142
11th to 20thNight
15%5%2342445%5%51%
2160
21st to endNight
14%424323446%55%
2376
November1st to 10thNight
14%6%24324335%53%
2221
11th to 20thNight
13%424424445%53%
2426
21st to endNight
13%5%2442445%8%49%
2470
December1st to 10thNight
16%6%35%5%3445%6%43%
2598
11th to 20thNight
14%6%245%3445%8%45%
3042
21st to endNight
18%5%25%5%35%5%6%8%38%
4532

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
40%410%23%18%5%
1707
11th to 20thDay
45%48%23%17%3
1638
21st to endDay
42%37%24%20%4
1782
February1st to 10thDay
46%410%21%16%3
1620
11th to 20thDay
46%38%23%16%4
1632
21st to endDay
46%410%16%17%6%
1549
March1st to 10thDay
35%48%25%22%5%
1980
11th to 20thDay
46%5%9%20%15%5%
1980
21st to endDay
48%5%9%22%14%3
2178
April1st to 10thDay
34%5%10%24%19%7%
2039
11th to 20thDay
38%411%22%18%5%
2134
21st to endDay
45%411%23%13%3
2280
May1st to 10thDay
45%6%15%19%12%3
2340
11th to 20thDay
48%6%13%21%9%2
2305
21st to endDay
44%7%15%24%9%
2531
June1st to 10thDay
39%7%16%25%12%1
2340
11th to 20thDay
39%8%17%20%14%2
2340
21st to endDay
40%8%14%24%12%2
2340
July1st to 10thDay
43%9%15%20%11%2
2275
11th to 20thDay
39%9%19%19%13%1
2271
21st to endDay
46%8%15%21%9%1
2405
August1st to 10thDay
47%6%16%22%8%1
2314
11th to 20thDay
47%8%14%21%9%1
2303
21st to endDay
43%7%17%19%11%3
2400
September1st to 10thDay
39%6%12%21%18%3
2120
11th to 20thDay
44%5%7%24%17%2
1980
21st to endDay
49%5%8%20%17%2
1980
October1st to 10thDay
38%49%25%19%4
1816
11th to 20thDay
36%49%26%21%5%
1800
21st to endDay
37%37%27%21%6%
1980
November1st to 10thDay
33%39%22%28%6%
1857
11th to 20thDay
35%37%24%24%7%
1752
21st to endDay
36%48%23%25%3
1710
December1st to 10thDay
46%5%10%17%18%4
1540
11th to 20thDay
34%48%23%24%7%
2150
21st to endDay
46%47%24%16%2
3124
January1st to 10thNight
38%410%23%19%7%
2459
11th to 20thNight
43%5%9%20%19%5%
2367
21st to endNight
39%39%25%21%4
2574
February1st to 10thNight
40%411%24%18%2
2340
11th to 20thNight
45%48%21%16%6%
2223
21st to endNight
42%410%24%14%5%
1705
March1st to 10thNight
34%5%9%26%20%6%
1980
11th to 20thNight
43%5%10%23%16%2
1980
21st to endNight
42%6%10%22%17%4
2178
April1st to 10thNight
39%410%21%21%4
1919
11th to 20thNight
36%312%21%22%6%
1775
21st to endNight
37%412%28%16%3
1694
May1st to 10thNight
41%5%15%24%13%2
1620
11th to 20thNight
45%6%14%23%11%1
1593
21st to endNight
39%6%19%27%9%
1745
June1st to 10thNight
34%10%17%26%13%
1620
11th to 20thNight
34%7%18%25%13%2
1620
21st to endNight
31%9%17%26%14%3
1620
July1st to 10thNight
37%9%17%20%12%5%
1575
11th to 20thNight
31%8%22%24%13%2
1566
21st to endNight
32%9%21%26%11%1
1672
August1st to 10thNight
42%7%19%21%10%1
1600
11th to 20thNight
39%7%16%25%12%1
1598
21st to endNight
38%6%18%25%11%3
1936
September1st to 10thNight
38%6%14%22%16%4
1836
11th to 20thNight
40%5%10%24%19%2
1980
21st to endNight
47%48%22%17%3
1980
October1st to 10thNight
39%48%24%21%4
2142
11th to 20thNight
35%38%29%20%5%
2160
21st to endNight
32%38%26%25%7%
2376
November1st to 10thNight
36%38%21%25%7%
2221
11th to 20thNight
34%37%23%25%8%
2426
21st to endNight
35%48%26%22%5%
2470
December1st to 10thNight
43%5%8%25%16%4
2598
11th to 20thNight
38%5%8%20%23%7%
3044
21st to endNight
43%49%22%20%2
4532

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
33%27%24%13%3
270
11th to 20thDay
30%28%30%11%
246
21st to endDay
30%31%28%8%3
264
February1st to 10thDay
31%25%33%10%2
240
11th to 20thDay
42%27%28%4
240
21st to endDay
33%28%23%13%2
267
March1st to 10thDay
25%27%28%16%5%
420
11th to 20thDay
30%25%25%15%5%1
420
21st to endDay
26%22%29%18%5%1
462
April1st to 10thDay
21%27%25%19%7%1
420
11th to 20thDay
23%17%27%18%11%3
412
21st to endDay
26%17%27%17%11%2
420
May1st to 10thDay
22%20%32%15%7%4
423
11th to 20thDay
18%14%25%25%12%6%
447
21st to endDay
20%7%21%25%20%7%
485
June1st to 10thDay
16%8%23%30%17%6%
450
11th to 20thDay
12%8%21%30%20%7%
450
21st to endDay
12%8%29%28%16%7%
450
July1st to 10thDay
12%5%14%30%28%11%
445
11th to 20thDay
6%5%16%34%30%9%
444
21st to endDay
12%6%16%31%25%11%
488
August1st to 10thDay
16%6%21%24%21%13%
446
11th to 20thDay
13%415%28%23%17%
439
21st to endDay
13%314%32%19%19%
495
September1st to 10thDay
17%415%26%25%14%
450
11th to 20thDay
19%414%28%24%11%
450
21st to endDay
28%9%17%26%14%4
450
October1st to 10thDay
23%8%19%26%19%6%
450
11th to 20thDay
17%17%24%23%16%3
450
21st to endDay
19%16%30%24%9%2
495
November1st to 10thDay
20%13%28%25%12%2
455
11th to 20thDay
25%21%27%18%8%1
312
21st to endDay
24%21%31%20%41
270
December1st to 10thDay
24%32%26%15%21
189
11th to 20thDay
23%25%32%15%5%
270
21st to endDay
28%21%31%14%5%
297
January1st to 10thNight
22%24%31%19%3
760
11th to 20thNight
23%20%30%25%3
729
21st to endNight
20%23%34%21%1
792
February1st to 10thNight
21%23%32%23%3
720
11th to 20thNight
29%25%29%16%1
703
21st to endNight
22%23%32%21%3
592
March1st to 10thNight
19%21%33%24%3
720
11th to 20thNight
24%19%29%20%7%1
720
21st to endNight
20%17%32%24%6%
792
April1st to 10thNight
22%19%29%23%7%
720
11th to 20thNight
19%14%28%26%12%1
711
21st to endNight
20%12%27%31%10%
614
May1st to 10thNight
19%9%29%27%14%1
540
11th to 20thNight
20%7%22%30%20%2
531
21st to endNight
16%314%31%30%5%
584
June1st to 10thNight
11%215%41%29%2
540
11th to 20thNight
12%5%13%33%34%4
540
21st to endNight
10%316%38%28%6%
540
July1st to 10thNight
12%49%36%34%6%
525
11th to 20thNight
8%9%33%44%6%
522
21st to endNight
6%211%38%37%5%
591
August1st to 10thNight
16%311%31%34%6%
537
11th to 20thNight
14%19%31%40%5%
534
21st to endNight
12%211%29%37%9%
748
September1st to 10thNight
15%311%30%33%8%
720
11th to 20thNight
18%311%30%31%7%
720
21st to endNight
25%6%16%27%23%3
720
October1st to 10thNight
19%8%18%23%25%6%
720
11th to 20thNight
20%11%23%28%16%2
720
21st to endNight
18%11%23%34%12%2
792
November1st to 10thNight
18%11%24%30%15%2
740
11th to 20thNight
20%16%24%29%10%1
760
21st to endNight
17%18%26%27%12%1
760
December1st to 10thNight
23%21%27%23%7%
760
11th to 20thNight
17%21%29%26%6%
760
21st to endNight
23%19%25%28%5%
836
Page generated at 2024-01-10 01:25:04. Version ac07

Copyright 2024 Attilla Danko


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