Elizabeth Ridge
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Elizabeth Ridge 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
37%
24515
23%
74590
13%
24465
47%
24465
28%
43902

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
35%
757
20%
2457
13%
756
44%
756
21%
1581
January11th to 20thNight
35%
732
24%
2379
16%
732
46%
732
23%
1496
January21st to endNight
31%
792
21%
2574
15%
792
40%
792
21%
1668
February1st to 10thNight
26%
720
19%
2340
11%
720
38%
720
17%
1534
February11th to 20thNight
28%
700
18%
2273
11%
700
39%
700
20%
1430
February21st to endNight
20%
592
21%
1785
8%
592
34%
592
17%
1208
March1st to 10thNight
24%
720
20%
1985
7%
720
37%
720
20%
1325
March11th to 20thNight
32%
720
22%
1980
10%
720
42%
720
29%
1199
March21st to endNight
23%
792
18%
2178
5%
792
34%
792
19%
1470
April1st to 10thNight
24%
648
18%
1908
8%
648
33%
648
20%
1238
April11th to 20thNight
22%
533
20%
1708
10%
533
34%
533
20%
1055
April21st to endNight
33%
540
19%
1620
10%
540
41%
540
23%
1020
May1st to 10thNight
34%
540
19%
1620
10%
540
41%
540
26%
1002
May11th to 20thNight
45%
531
20%
1595
15%
531
50%
531
32%
910
May21st to endNight
37%
584
17%
1635
10%
582
45%
582
30%
972
June1st to 10thNight
42%
540
21%
1440
11%
540
51%
540
39%
804
June11th to 20thNight
40%
540
27%
1440
12%
540
54%
540
44%
745
June21st to endNight
53%
540
30%
1440
19%
540
64%
540
57%
708
July1st to 10thNight
58%
525
21%
1501
14%
525
66%
525
43%
789
July11th to 20thNight
57%
522
22%
1566
19%
522
62%
522
39%
841
July21st to endNight
66%
591
23%
1674
17%
558
70%
558
40%
906
August1st to 10thNight
55%
537
24%
1602
15%
534
62%
534
40%
861
August11th to 20thNight
62%
534
33%
1602
22%
534
69%
534
48%
793
August21st to endNight
58%
594
35%
1849
26%
594
67%
594
47%
876
September1st to 10thNight
58%
574
35%
1834
24%
574
72%
574
47%
847
September11th to 20thNight
51%
720
33%
1980
18%
720
64%
720
48%
1006
September21st to endNight
48%
720
35%
1980
19%
720
59%
720
46%
1009
October1st to 10thNight
43%
720
24%
2119
13%
720
53%
720
31%
1208
October11th to 20thNight
44%
720
32%
2160
17%
720
57%
720
37%
1155
October21st to endNight
39%
792
28%
2376
15%
792
51%
792
31%
1325
November1st to 10thNight
36%
740
25%
2346
15%
740
47%
740
27%
1320
November11th to 20thNight
31%
831
25%
2541
13%
831
43%
831
27%
1455
November21st to endNight
34%
950
23%
2660
12%
950
44%
950
27%
1640
December1st to 10thNight
29%
950
18%
2660
8%
950
37%
950
24%
1731
December11th to 20thNight
26%
950
22%
3102
9%
949
36%
949
20%
1924
December21st to endNight
21%
1024
11%
4681
6%
1014
29%
1014
10%
2851

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
49%48%7%35%5%6%7%43%
74629
Night
26%47%6%35%5%6%8%49%
75144
TransparencyDay
41%49%21%18%7%
74354
Night
35%411%24%19%7%
74940
SeeingDay
16%29%28%17%8%2
14202
Night
9%20%28%27%13%2
24531

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
110%7%11%7%35%45%7%40%
1708
11th to 20thDay
18%7%12%7%5%5%45%5%42%
1642
21st to endDay
18%6%14%10%3445%6%40%
1782
February1st to 10thDay
112%6%12%10%45%45%6%34%
1620
11th to 20thDay
8%8%15%8%445%47%36%
1575
21st to endDay
8%8%13%14%5%5%47%6%30%
1467
March1st to 10thDay
8%6%12%11%45%5%6%9%34%
1975
11th to 20thDay
110%7%11%6%45%5%6%8%38%
1980
21st to endDay
113%9%15%10%35%5%5%7%27%
2178
April1st to 10thDay
314%6%10%7%3446%7%37%
2052
11th to 20thDay
215%7%12%8%35%45%6%33%
2195
21st to endDay
414%6%10%6%345%5%7%37%
2340
May1st to 10thDay
6%13%5%8%7%45%6%6%7%34%
2340
11th to 20thDay
5%13%47%7%36%5%7%9%35%
2301
21st to endDay
5%13%48%7%46%6%7%8%31%
2637
June1st to 10thDay
6%6%36%5%46%5%6%7%47%
2520
11th to 20thDay
6%6%3442345%8%54%
2520
21st to endDay
4424425%5%5%8%57%
2520
July1st to 10thDay
6%5%36%6%46%5%6%8%45%
2409
11th to 20thDay
6%6%36%6%36%6%6%7%45%
2340
21st to endDay
8%6%37%7%5%5%6%6%7%40%
2545
August1st to 10thDay
7%6%37%7%5%6%6%6%7%41%
2328
11th to 20thDay
5%5%36%6%45%6%6%8%47%
2299
21st to endDay
6%6%36%7%35%5%6%6%46%
2507
September1st to 10thDay
6%5%25%5%4445%5%56%
2123
11th to 20thDay
5%6%25%4345%5%7%55%
1980
21st to endDay
6%8%25%42243460%
1980
October1st to 10thDay
413%36%5%33446%50%
1841
11th to 20thDay
39%25%5%22445%59%
1800
21st to endDay
18%47%5%3445%7%53%
1980
November1st to 10thDay
28%5%9%4245%7%7%48%
1729
11th to 20thDay
210%5%6%5%2446%7%49%
1616
21st to endDay
16%410%9%45%6%5%7%45%
1520
December1st to 10thDay
18%5%10%7%5%6%45%8%42%
1520
11th to 20thDay
18%5%11%8%45%6%7%9%36%
1926
21st to endDay
6%6%11%9%45%45%7%41%
2834
January1st to 10thNight
18%5%10%10%36%45%8%40%
2457
11th to 20thNight
16%6%10%7%5%5%45%7%45%
2379
21st to endNight
16%7%13%8%45%45%8%40%
2574
February1st to 10thNight
10%6%10%8%45%5%6%8%38%
2340
11th to 20thNight
15%6%11%9%45%5%6%7%41%
2272
21st to endNight
6%411%13%45%46%8%38%
1785
March1st to 10thNight
16%6%10%10%45%5%6%9%39%
1985
11th to 20thNight
5%49%5%35%5%6%10%47%
1980
21st to endNight
110%6%11%7%345%6%7%41%
2178
April1st to 10thNight
210%6%7%6%35%5%46%45%
1908
11th to 20thNight
211%48%7%25%5%6%9%42%
1708
21st to endNight
311%6%9%435%45%8%43%
1620
May1st to 10thNight
49%45%5%46%6%7%8%42%
1620
11th to 20thNight
47%246%35%5%7%9%48%
1594
21st to endNight
46%25%5%35%7%8%11%44%
1635
June1st to 10thNight
34235%35%5%6%11%53%
1440
11th to 20thNight
3314314448%65%
1440
21st to endNight
221332246%7%69%
1440
July1st to 10thNight
32135%36%48%8%57%
1546
11th to 20thNight
3415%5%446%6%8%53%
1620
21st to endNight
33145%37%7%8%8%52%
1773
August1st to 10thNight
33145%346%7%8%54%
1611
11th to 20thNight
332242347%9%60%
1602
21st to endNight
2213425%46%8%63%
1849
September1st to 10thNight
231232345%7%67%
1834
11th to 20thNight
23233235%6%7%64%
1980
21st to endNight
35%1332335%5%67%
1980
October1st to 10thNight
26%35%5%4446%5%56%
2119
11th to 20thNight
36%3432445%6%61%
2160
21st to endNight
28%36%32445%7%55%
2376
November1st to 10thNight
18%46%43446%8%52%
2346
11th to 20thNight
17%46%5%245%7%8%49%
2541
21st to endNight
16%49%6%35%45%7%49%
2660
December1st to 10thNight
18%5%9%8%4446%7%44%
2660
11th to 20thNight
17%310%8%35%6%7%11%40%
3271
21st to endNight
16%5%10%11%5%5%6%6%8%37%
4861

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
46%5%12%21%14%3
1709
11th to 20thDay
46%412%18%14%7%
1642
21st to endDay
47%412%20%12%5%
1782
February1st to 10thDay
52%6%7%16%15%3
1620
11th to 20thDay
49%5%9%19%13%4
1584
21st to endDay
55%5%9%16%11%4
1467
March1st to 10thDay
49%411%22%11%2
1975
11th to 20thDay
46%5%15%18%10%6%
1980
21st to endDay
58%411%16%7%2
2178
April1st to 10thDay
49%412%19%13%4
2052
11th to 20thDay
55%39%21%11%2
2198
21st to endDay
47%411%26%10%1
2340
May1st to 10thDay
49%39%23%15%1
2340
11th to 20thDay
46%412%28%10%1
2304
21st to endDay
50%412%21%12%1
2637
June1st to 10thDay
35%410%29%18%4
2520
11th to 20thDay
31%37%21%28%10%
2520
21st to endDay
25%3420%31%16%
2520
July1st to 10thDay
37%45%16%24%14%
2345
11th to 20thDay
37%46%16%22%15%
2271
21st to endDay
42%48%14%22%10%
2404
August1st to 10thDay
40%5%7%18%19%12%
2313
11th to 20thDay
35%46%19%25%12%
2299
21st to endDay
37%5%5%20%24%9%
2507
September1st to 10thDay
31%45%15%28%18%
2123
11th to 20thDay
31%37%22%23%14%
1980
21st to endDay
30%36%26%29%7%
1980
October1st to 10thDay
39%36%25%19%8%
1841
11th to 20thDay
29%39%29%24%6%
1800
21st to endDay
34%312%27%20%4
1980
November1st to 10thDay
36%6%10%25%19%5%
1729
11th to 20thDay
35%413%23%20%5%
1616
21st to endDay
40%5%10%21%17%7%
1520
December1st to 10thDay
42%6%15%18%13%7%
1520
11th to 20thDay
46%311%22%17%1
1924
21st to endDay
45%35%17%16%15%
2834
January1st to 10thNight
45%313%19%15%5%
2457
11th to 20thNight
42%411%21%15%7%
2379
21st to endNight
46%410%21%12%7%
2574
February1st to 10thNight
45%6%11%21%16%2
2340
11th to 20thNight
42%49%20%19%6%
2273
21st to endNight
47%5%9%18%15%6%
1785
March1st to 10thNight
44%411%23%16%2
1985
11th to 20thNight
34%417%26%13%6%
1980
21st to endNight
44%5%14%23%10%3
2178
April1st to 10thNight
42%5%11%20%14%7%
1908
11th to 20thNight
40%5%13%26%14%2
1708
21st to endNight
42%315%27%13%1
1620
May1st to 10thNight
38%412%29%14%2
1620
11th to 20thNight
32%416%33%15%1
1595
21st to endNight
34%417%31%12%2
1635
June1st to 10thNight
25%415%30%20%5%
1440
11th to 20thNight
21%210%24%33%10%
1440
21st to endNight
15%3422%40%16%
1440
July1st to 10thNight
24%48%19%32%13%
1501
11th to 20thNight
27%49%19%25%16%
1566
21st to endNight
26%6%13%22%22%11%
1674
August1st to 10thNight
25%6%12%21%23%13%
1602
11th to 20thNight
21%49%25%28%13%
1602
21st to endNight
20%39%27%28%12%
1849
September1st to 10thNight
18%37%22%30%19%
1834
11th to 20thNight
20%212%25%27%14%
1980
21st to endNight
20%36%29%35%6%
1980
October1st to 10thNight
31%310%25%22%8%
2119
11th to 20thNight
26%48%31%25%7%
2160
21st to endNight
30%413%28%18%6%
2376
November1st to 10thNight
32%5%12%24%22%6%
2346
11th to 20thNight
33%415%25%18%5%
2541
21st to endNight
36%410%21%19%9%
2660
December1st to 10thNight
41%5%14%20%14%7%
2660
11th to 20thNight
40%412%26%15%3
3272
21st to endNight
47%36%18%12%12%
4861

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
23%25%25%16%10%1
270
11th to 20thDay
15%32%27%18%9%
248
21st to endDay
11%33%34%16%41
264
February1st to 10thDay
26%40%22%8%3
240
11th to 20thDay
21%37%24%12%6%
240
21st to endDay
20%45%26%6%2
333
March1st to 10thDay
17%46%25%9%2
420
11th to 20thDay
16%35%31%14%3
420
21st to endDay
20%42%28%8%1
462
April1st to 10thDay
23%40%20%12%41
420
11th to 20thDay
28%40%23%5%31
412
21st to endDay
23%38%21%13%5%
420
May1st to 10thDay
22%30%30%12%5%1
423
11th to 20thDay
20%27%28%16%6%2
448
21st to endDay
20%22%28%16%11%2
592
June1st to 10thDay
11%24%30%23%10%3
630
11th to 20thDay
14%30%30%18%7%1
630
21st to endDay
7%23%36%20%10%3
630
July1st to 10thDay
7%21%31%26%12%3
515
11th to 20thDay
7%24%38%19%10%2
444
21st to endDay
9%14%36%25%12%4
487
August1st to 10thDay
10%23%30%27%8%2
447
11th to 20thDay
7%19%36%26%10%3
437
21st to endDay
8%25%30%24%10%2
495
September1st to 10thDay
11%24%28%24%11%3
450
11th to 20thDay
13%32%27%16%10%3
450
21st to endDay
15%25%28%21%9%2
450
October1st to 10thDay
16%26%27%18%11%2
311
11th to 20thDay
17%24%24%20%13%1
270
21st to endDay
20%31%24%19%6%
297
November1st to 10thDay
24%32%20%16%7%1
270
11th to 20thDay
20%29%27%14%6%3
270
21st to endDay
10%26%33%22%8%2
270
December1st to 10thDay
18%31%24%18%8%2
270
11th to 20thDay
19%27%32%18%41
270
21st to endDay
21%35%25%12%6%1
297
January1st to 10thNight
12%22%25%26%13%3
760
11th to 20thNight
11%22%27%25%13%2
732
21st to endNight
7%25%31%26%9%2
792
February1st to 10thNight
14%27%28%21%8%2
720
11th to 20thNight
9%30%28%24%9%2
704
21st to endNight
15%27%34%20%41
592
March1st to 10thNight
10%29%33%19%7%2
720
11th to 20thNight
6%24%33%25%11%1
720
21st to endNight
10%32%31%21%7%
792
April1st to 10thNight
14%29%29%20%7%1
648
11th to 20thNight
15%27%32%19%7%
533
21st to endNight
12%23%26%25%11%2
540
May1st to 10thNight
12%16%34%26%10%1
540
11th to 20thNight
10%13%28%32%15%3
531
21st to endNight
11%17%29%28%13%2
584
June1st to 10thNight
6%16%32%29%16%1
540
11th to 20thNight
7%17%32%31%11%1
540
21st to endNight
39%32%32%21%3
540
July1st to 10thNight
47%26%33%26%4
525
11th to 20thNight
46%22%43%21%3
522
21st to endNight
3417%39%34%3
591
August1st to 10thNight
5%6%26%39%23%2
537
11th to 20thNight
4423%39%27%2
534
21st to endNight
47%26%31%28%3
594
September1st to 10thNight
412%21%35%24%4
574
11th to 20thNight
6%13%26%29%21%6%
720
21st to endNight
7%17%24%26%19%7%
720
October1st to 10thNight
9%22%23%29%13%4
720
11th to 20thNight
9%19%25%29%15%4
720
21st to endNight
11%25%24%26%11%4
792
November1st to 10thNight
13%22%26%24%14%2
740
11th to 20thNight
13%24%29%23%10%2
831
21st to endNight
9%27%26%24%11%3
950
December1st to 10thNight
13%25%28%25%8%1
950
11th to 20thNight
10%25%34%22%7%1
950
21st to endNight
15%27%30%21%6%2
1033
Page generated at 2024-01-10 17:35:24. Version ac07

Copyright 2024 Attilla Danko


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