Cameron
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cameron clear sky chart from 2005-11-06 to 2024-03-18.

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
39%
24794
21%
80496
12%
24686
48%
24686
27%
50054

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
26%
942
16%
4095
9%
926
37%
926
16%
2842
January11th to 20thNight
22%
949
20%
4020
6%
930
33%
930
15%
2669
January21st to endNight
24%
1037
12%
4497
5%
1023
33%
1023
13%
3248
February1st to 10thNight
23%
950
16%
2470
5%
950
29%
950
23%
1741
February11th to 20thNight
28%
929
18%
2404
6%
925
35%
925
27%
1615
February21st to endNight
20%
624
22%
1880
6%
624
34%
624
26%
1165
March1st to 10thNight
26%
570
23%
2090
11%
570
42%
570
24%
1209
March11th to 20thNight
28%
564
19%
2068
11%
564
39%
564
19%
1300
March21st to endNight
20%
594
12%
2178
6%
594
28%
594
14%
1532
April1st to 10thNight
29%
540
21%
1854
12%
540
42%
540
26%
1066
April11th to 20thNight
28%
533
21%
1775
13%
533
42%
533
24%
1094
April21st to endNight
30%
540
21%
1682
12%
540
44%
540
25%
1076
May1st to 10thNight
32%
540
16%
1620
9%
540
41%
540
23%
1075
May11th to 20thNight
42%
531
19%
1594
14%
531
50%
531
28%
1003
May21st to endNight
47%
584
19%
1573
11%
582
53%
582
31%
1010
June1st to 10thNight
65%
540
23%
1440
14%
540
69%
540
44%
818
June11th to 20thNight
60%
540
22%
1440
13%
540
63%
540
41%
851
June21st to endNight
59%
540
25%
1440
14%
540
63%
540
51%
774
July1st to 10thNight
71%
525
19%
1443
14%
525
72%
525
44%
814
July11th to 20thNight
72%
522
23%
1566
20%
522
75%
522
48%
794
July21st to endNight
71%
591
24%
1673
24%
558
74%
558
41%
896
August1st to 10thNight
70%
537
22%
1601
22%
534
74%
534
42%
869
August11th to 20thNight
69%
534
29%
1600
30%
534
74%
534
42%
862
August21st to endNight
72%
594
28%
1934
30%
594
75%
594
43%
987
September1st to 10thNight
63%
540
26%
1800
25%
540
68%
540
36%
975
September11th to 20thNight
63%
540
30%
1916
30%
540
69%
540
38%
994
September21st to endNight
57%
556
29%
1996
24%
556
65%
556
37%
1001
October1st to 10thNight
47%
720
24%
2160
17%
720
51%
720
36%
1238
October11th to 20thNight
34%
720
27%
2160
13%
720
46%
720
34%
1241
October21st to endNight
31%
792
25%
2376
11%
792
42%
792
28%
1451
November1st to 10thNight
41%
740
31%
2220
16%
740
54%
740
39%
1166
November11th to 20thNight
30%
945
25%
2621
9%
945
43%
945
32%
1572
November21st to endNight
30%
950
22%
2660
9%
950
41%
950
29%
1673
December1st to 10thNight
30%
950
19%
2660
7%
950
40%
950
25%
1744
December11th to 20thNight
26%
949
21%
3149
7%
948
35%
948
22%
1943
December21st to endNight
22%
1042
13%
4841
6%
1026
35%
1026
10%
3746

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
12%7%36%5%3445%7%42%
78789
Night
11%7%36%5%3445%6%46%
81047
TransparencyDay
41%6%13%24%14%2
78509
Night
39%5%12%25%16%3
80847
SeeingDay
15%10%29%28%15%4
14746
Night
14%9%32%32%11%1
24815

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%10%48%6%2446%8%34%
2815
11th to 20thDay
10%12%5%9%7%48%335%35%
2850
21st to endDay
13%14%7%13%6%44445%26%
3135
February1st to 10thDay
14%9%5%7%6%35%46%6%35%
1710
11th to 20thDay
12%9%6%6%5%3335%8%41%
1664
21st to endDay
11%10%47%43445%6%42%
1589
March1st to 10thDay
13%10%37%5%3445%5%41%
2090
11th to 20thDay
17%12%46%434346%37%
2057
21st to endDay
22%12%48%6%34446%28%
2178
April1st to 10thDay
14%7%46%5%335%5%7%42%
2106
11th to 20thDay
15%8%37%5%25%45%7%39%
2134
21st to endDay
21%7%37%5%345%46%35%
2276
May1st to 10thDay
16%9%45%5%45%5%6%7%34%
2340
11th to 20thDay
16%7%36%6%35%448%38%
2302
21st to endDay
14%7%47%5%45%5%6%7%37%
2699
June1st to 10thDay
6%4246%35%6%7%9%47%
2520
11th to 20thDay
7%5%25%5%35%5%7%9%47%
2520
21st to endDay
8%4245%35%6%6%9%48%
2520
July1st to 10thDay
8%434435%5%7%9%48%
2469
11th to 20thDay
7%4245%35%5%6%8%50%
2340
21st to endDay
7%335%5%35%5%6%10%47%
2546
August1st to 10thDay
7%5%25%6%45%6%8%9%42%
2328
11th to 20thDay
9%5%25%436%46%8%48%
2301
21st to endDay
9%425%43446%8%53%
2422
September1st to 10thDay
12%5%2343445%7%52%
2160
11th to 20thDay
9%4345%245%5%8%51%
2039
21st to endDay
9%423434445%57%
1944
October1st to 10thDay
13%7%2443435%6%49%
1800
11th to 20thDay
14%6%25%434345%53%
1800
21st to endDay
14%7%35%434346%47%
1980
November1st to 10thDay
9%5%2442346%7%53%
1858
11th to 20thDay
13%6%345%2345%6%48%
1556
21st to endDay
16%9%45%32335%7%43%
1520
December1st to 10thDay
10%9%37%6%435%5%8%42%
1520
11th to 20thDay
12%9%47%6%44446%41%
1918
21st to endDay
17%14%7%13%5%34445%24%
2783
January1st to 10thNight
9%9%412%9%45%45%6%34%
4136
11th to 20thNight
11%9%5%7%6%38%6%6%5%35%
4120
21st to endNight
14%12%6%12%5%34445%31%
4532
February1st to 10thNight
11%11%5%8%5%4445%5%37%
2470
11th to 20thNight
12%7%47%5%3445%6%42%
2403
21st to endNight
12%8%4443345%5%47%
1880
March1st to 10thNight
11%7%45%424445%48%
2090
11th to 20thNight
15%9%36%5%2445%7%41%
2068
21st to endNight
22%10%47%5%3445%6%31%
2178
April1st to 10thNight
10%6%36%434447%50%
1854
11th to 20thNight
14%7%35%5%34446%45%
1775
21st to endNight
15%8%45%4235%5%6%43%
1682
May1st to 10thNight
14%6%26%5%35%5%6%8%40%
1620
11th to 20thNight
14%6%25%42445%8%45%
1593
21st to endNight
9%5%25%6%35%45%9%46%
1572
June1st to 10thNight
5%214335%5%7%10%55%
1440
11th to 20thNight
4324446%47%10%51%
1440
21st to endNight
5%31342435%11%60%
1440
July1st to 10thNight
6%425%32446%9%54%
1485
11th to 20thNight
431333446%9%61%
1620
21st to endNight
5%3145%45%5%6%10%52%
1772
August1st to 10thNight
5%323435%5%7%11%53%
1611
11th to 20thNight
6%42443435%8%57%
1600
21st to endNight
7%324434347%60%
1934
September1st to 10thNight
10%424424447%56%
1800
11th to 20thNight
10%4133345%5%7%55%
1916
21st to endNight
7%424424447%58%
1996
October1st to 10thNight
11%6%24423446%55%
2160
11th to 20thNight
14%5%24433345%54%
2160
21st to endNight
17%7%25%42324451%
2376
November1st to 10thNight
8%423323347%61%
2220
11th to 20thNight
11%6%24433445%53%
2621
21st to endNight
14%8%25%423345%49%
2660
December1st to 10thNight
11%9%35%5%35%5%5%6%44%
2660
11th to 20thNight
12%9%37%423446%45%
3279
21st to endNight
19%16%7%10%5%3333427%
4884

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
48%6%14%22%10%1
2816
11th to 20thDay
54%413%19%10%
2850
21st to endDay
60%5%10%16%8%1
3135
February1st to 10thDay
50%5%12%20%10%3
1710
11th to 20thDay
44%412%24%14%2
1673
21st to endDay
42%5%11%22%18%3
1589
March1st to 10thDay
45%5%11%23%14%2
2090
11th to 20thDay
49%5%8%23%12%2
2057
21st to endDay
57%5%12%17%7%1
2178
April1st to 10thDay
42%5%12%25%14%2
2106
11th to 20thDay
45%5%13%22%14%1
2134
21st to endDay
49%6%12%22%11%1
2276
May1st to 10thDay
48%8%13%19%12%1
2340
11th to 20thDay
45%6%14%23%12%
2306
21st to endDay
46%7%14%20%11%2
2699
June1st to 10thDay
30%10%15%31%13%2
2520
11th to 20thDay
31%7%15%26%19%1
2520
21st to endDay
30%7%16%29%15%3
2520
July1st to 10thDay
31%8%17%28%12%4
2402
11th to 20thDay
31%8%13%27%17%4
2271
21st to endDay
30%6%15%32%16%1
2405
August1st to 10thDay
34%9%18%25%13%1
2314
11th to 20thDay
33%6%12%31%17%1
2301
21st to endDay
29%7%13%26%19%6%
2422
September1st to 10thDay
31%6%12%27%18%6%
2160
11th to 20thDay
31%6%12%27%22%2
2039
21st to endDay
29%5%9%33%22%3
1944
October1st to 10thDay
35%5%12%27%19%2
1800
11th to 20thDay
35%47%27%22%5%
1800
21st to endDay
40%411%23%17%5%
1980
November1st to 10thDay
30%5%14%27%20%4
1858
11th to 20thDay
36%5%11%27%19%2
1556
21st to endDay
42%5%10%26%17%
1520
December1st to 10thDay
41%7%13%24%14%1
1520
11th to 20thDay
45%6%15%27%7%1
1915
21st to endDay
63%410%15%6%1
2783
January1st to 10thNight
50%6%11%21%11%1
4136
11th to 20thNight
49%5%12%21%12%1
4120
21st to endNight
55%5%13%16%8%1
4532
February1st to 10thNight
48%412%19%13%3
2470
11th to 20thNight
42%413%22%16%3
2404
21st to endNight
38%5%11%23%18%6%
1880
March1st to 10thNight
38%412%26%18%3
2090
11th to 20thNight
43%6%10%22%15%3
2068
21st to endNight
54%5%12%18%9%2
2178
April1st to 10thNight
35%5%11%27%18%4
1854
11th to 20thNight
40%5%10%28%14%3
1775
21st to endNight
41%5%11%25%16%1
1682
May1st to 10thNight
42%7%13%22%14%2
1620
11th to 20thNight
38%7%13%26%16%1
1594
21st to endNight
37%7%15%26%13%2
1573
June1st to 10thNight
23%8%17%32%16%3
1440
11th to 20thNight
26%9%15%28%20%3
1440
21st to endNight
21%5%17%34%19%4
1440
July1st to 10thNight
26%5%15%32%18%3
1443
11th to 20thNight
19%8%16%32%22%3
1566
21st to endNight
25%6%13%37%18%2
1673
August1st to 10thNight
25%7%20%30%18%2
1601
11th to 20thNight
26%413%34%22%1
1600
21st to endNight
24%412%27%24%8%
1934
September1st to 10thNight
29%5%11%27%21%8%
1800
11th to 20thNight
27%5%12%29%24%3
1916
21st to endNight
27%49%30%26%4
1996
October1st to 10thNight
31%410%26%24%5%
2160
11th to 20thNight
33%38%27%22%8%
2160
21st to endNight
38%39%22%23%3
2376
November1st to 10thNight
25%5%14%28%23%6%
2220
11th to 20thNight
34%49%29%20%4
2621
21st to endNight
39%411%27%17%3
2660
December1st to 10thNight
40%6%12%27%14%1
2660
11th to 20thNight
41%412%30%12%1
3281
21st to endNight
63%46%17%8%1
4884

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
20%17%34%23%6%
270
11th to 20thDay
25%13%45%15%1
270
21st to endDay
15%16%43%23%3
297
February1st to 10thDay
21%21%40%17%2
270
11th to 20thDay
18%18%44%13%6%1
270
21st to endDay
16%22%44%17%2
225
March1st to 10thDay
19%15%47%17%2
270
11th to 20thDay
29%11%33%22%4
261
21st to endDay
39%16%28%15%2
264
April1st to 10thDay
21%14%37%21%7%1
366
11th to 20thDay
17%14%39%24%7%
412
21st to endDay
24%13%35%18%8%1
536
May1st to 10thDay
19%12%35%24%8%1
603
11th to 20thDay
20%10%32%25%12%2
625
21st to endDay
17%8%27%27%18%3
679
June1st to 10thDay
6%5%20%36%24%8%
630
11th to 20thDay
8%425%40%19%4
630
21st to endDay
7%7%33%38%13%2
630
July1st to 10thDay
9%413%32%32%10%
621
11th to 20thDay
7%421%35%24%8%
618
21st to endDay
7%215%42%29%4
684
August1st to 10thDay
7%218%38%28%6%
626
11th to 20thDay
8%417%36%28%7%
615
21st to endDay
10%115%36%27%11%
541
September1st to 10thDay
13%218%31%29%6%
450
11th to 20thDay
10%218%36%27%6%
329
21st to endDay
13%8%27%32%15%5%
270
October1st to 10thDay
19%7%26%29%15%5%
270
11th to 20thDay
14%23%36%19%7%1
270
21st to endDay
19%16%35%21%8%1
297
November1st to 10thDay
15%10%40%26%7%3
270
11th to 20thDay
17%18%34%23%5%3
270
21st to endDay
21%15%34%23%6%1
270
December1st to 10thDay
11%18%37%26%6%2
270
11th to 20thDay
21%14%35%23%6%1
270
21st to endDay
21%21%39%18%1
297
January1st to 10thNight
13%14%41%26%6%
950
11th to 20thNight
16%14%41%23%6%1
950
21st to endNight
16%13%40%27%4
1045
February1st to 10thNight
16%14%42%25%3
950
11th to 20thNight
16%14%37%28%4
929
21st to endNight
18%16%44%18%4
624
March1st to 10thNight
14%14%41%25%6%
570
11th to 20thNight
20%11%36%26%6%1
564
21st to endNight
26%10%37%22%5%
594
April1st to 10thNight
13%14%40%29%4
540
11th to 20thNight
19%11%38%26%7%
533
21st to endNight
20%9%36%26%6%1
540
May1st to 10thNight
18%9%35%30%7%1
540
11th to 20thNight
17%6%30%34%11%1
531
21st to endNight
12%5%28%37%16%2
584
June1st to 10thNight
6%421%46%20%3
540
11th to 20thNight
6%326%46%18%2
540
21st to endNight
6%426%51%13%
540
July1st to 10thNight
8%211%43%33%3
525
11th to 20thNight
4216%49%27%2
522
21st to endNight
7%113%46%32%2
591
August1st to 10thNight
5%216%50%26%1
537
11th to 20thNight
7%215%44%30%2
534
21st to endNight
7%213%45%30%3
594
September1st to 10thNight
11%318%40%24%4
540
11th to 20thNight
11%220%42%22%3
540
21st to endNight
7%5%25%40%20%2
556
October1st to 10thNight
13%5%31%33%16%2
720
11th to 20thNight
16%9%36%30%8%
720
21st to endNight
21%10%34%27%8%
792
November1st to 10thNight
10%11%35%34%9%1
740
11th to 20thNight
14%15%39%25%8%
945
21st to endNight
18%11%35%29%6%
950
December1st to 10thNight
16%12%37%27%7%1
950
11th to 20thNight
20%8%39%27%6%
950
21st to endNight
20%15%37%25%3
1045
Page generated at 2024-03-15 13:01:41. Version ac07

Copyright © 2024 Attilla Danko.


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