Independence Mountain
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Independence Mountain clear sky chart from 2005-11-05 to 2018-10-08.

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
42%
17398
21%
51045
13%
17356
50%
17356
32%
30435

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 15thNight
26%
974
15%
2716
7%
970
33%
970
24%
1832
January16th to endNight
29%
848
21%
2720
11%
848
40%
848
26%
1672
February1st to 15thNight
22%
756
9%
2483
4%
756
29%
756
15%
1752
February16th to endNight
21%
684
17%
2073
4%
684
35%
684
22%
1349
March1st to 15thNight
32%
780
20%
2233
9%
780
43%
780
32%
1335
March16th to endNight
30%
776
18%
2232
10%
776
39%
776
30%
1384
April1st to 15thNight
31%
584
15%
1948
8%
584
41%
584
25%
1177
April16th to endNight
36%
579
18%
1929
14%
579
45%
579
26%
1155
May1st to 15thNight
44%
585
18%
1670
11%
585
49%
585
27%
1076
May16th to endNight
57%
611
18%
1626
12%
609
61%
609
35%
987
June1st to 15thNight
61%
585
23%
1560
15%
585
66%
585
52%
805
June16th to endNight
69%
585
28%
1560
22%
585
73%
585
62%
759
July1st to 15thNight
78%
555
20%
1480
17%
555
79%
555
48%
804
July16th to endNight
83%
612
22%
1606
20%
579
83%
579
48%
855
August1st to 15thNight
77%
575
23%
1719
21%
572
78%
572
44%
897
August16th to endNight
77%
621
29%
2058
30%
621
81%
621
43%
1045
September1st to 15thNight
70%
585
31%
1950
30%
585
77%
585
45%
963
September16th to endNight
60%
644
33%
2113
28%
644
67%
644
47%
1014
October1st to 15thNight
42%
752
25%
2256
14%
752
51%
752
34%
1319
October16th to endNight
42%
768
30%
2304
15%
768
55%
768
39%
1227
November1st to 15thNight
33%
949
23%
2469
10%
949
41%
949
38%
1491
November16th to endNight
28%
975
23%
2698
8%
975
41%
975
35%
1583
December1st to 15thNight
20%
975
11%
2730
4%
975
26%
975
22%
1862
December16th to endNight
20%
1040
14%
2912
4%
1040
29%
1040
18%
2092

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
35%25%5%35%5%6%8%47%
52098
Night
242442445%8%54%
51222
TransparencyDay
33%10%15%20%15%4
51777
Night
27%10%17%24%15%4
51045
SeeingDay
7%18%31%25%14%2
7299
Night
412%35%30%15%1
17407

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 15thDay
237%6%46%7%6%8%45%
1552
16th to endDay
438%7%3346%9%48%
1866
February1st to 15thDay
45%9%9%5%6%6%7%8%36%
1710
16th to endDay
45%9%6%47%6%6%9%39%
1685
March1st to 15thDay
426%6%345%6%9%49%
2054
16th to endDay
26%47%6%35%6%7%9%40%
2343
April1st to 15thDay
29%46%5%45%6%6%7%42%
2330
16th to endDay
310%37%6%46%6%5%9%36%
2306
May1st to 15thDay
7%8%35%6%35%6%6%7%39%
2607
16th to endDay
6%6%27%6%46%6%7%10%37%
2840
June1st to 15thDay
431343446%9%53%
2730
16th to endDay
2123235%5%7%65%
2730
July1st to 15thDay
43246%36%6%5%7%50%
2730
16th to endDay
5%4245%46%6%6%9%44%
2810
August1st to 15thDay
45%25%7%36%6%6%8%42%
2485
16th to endDay
34145%46%5%5%8%50%
2494
September1st to 15thDay
5%32442345%6%56%
2340
16th to endDay
5%5%14323345%61%
2174
October1st to 15thDay
5%6%245%345%5%5%51%
1873
16th to endDay
25%2432445%7%56%
1908
November1st to 15thDay
15%45%425%46%7%52%
1718
16th to endDay
1335%5%345%47%54%
1589
December1st to 15thDay
6%39%6%35%5%7%10%39%
1560
16th to endDay
6%310%7%37%5%6%8%39%
1664
January1st to 15thNight
324436%5%6%10%52%
2716
16th to endNight
226%6%345%6%9%52%
2720
February1st to 15thNight
327%7%47%6%7%9%42%
2472
16th to endNight
447%6%445%6%9%46%
2073
March1st to 15thNight
32442346%8%57%
2233
16th to endNight
25%25%435%5%5%9%51%
2232
April1st to 15thNight
26%25%426%5%5%8%50%
1948
16th to endNight
48%35%32445%6%50%
1929
May1st to 15thNight
6%7%245%245%5%8%46%
1669
16th to endNight
4413335%5%7%9%51%
1625
June1st to 15thNight
312214448%66%
1560
16th to endNight
11121235%6%72%
1560
July1st to 15thNight
321122436%9%60%
1560
16th to endNight
1112325%46%8%60%
1707
August1st to 15thNight
2234245%6%9%57%
1728
16th to endNight
2234335%6%8%60%
2058
September1st to 15thNight
4212323448%62%
1950
16th to endNight
5%312212236%68%
2113
October1st to 15thNight
5%5%1342336%6%56%
2256
16th to endNight
3413323337%62%
2304
November1st to 15thNight
232432345%8%58%
2469
16th to endNight
122443446%9%57%
2698
December1st to 15thNight
6%26%5%346%6%10%46%
2730
16th to endNight
15%38%7%35%6%6%10%41%
2912

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 15thDay
35%16%22%14%8%1
1553
16th to endDay
35%12%21%20%8%1
1866
February1st to 15thDay
45%14%18%14%6%
1710
16th to endDay
39%12%21%18%7%
1685
March1st to 15thDay
31%12%21%21%12%
2054
16th to endDay
37%13%16%21%8%1
2343
April1st to 15thDay
38%11%16%19%11%2
2330
16th to endDay
40%11%16%21%8%
2306
May1st to 15thDay
40%10%16%21%11%
2607
16th to endDay
38%10%15%23%11%1
2844
June1st to 15thDay
24%7%14%20%23%9%
2730
16th to endDay
17%5%9%21%32%13%
2730
July1st to 15thDay
29%8%12%16%19%13%
2581
16th to endDay
31%9%14%19%15%10%
2648
August1st to 15thDay
36%10%11%14%17%9%
2470
16th to endDay
29%9%11%21%21%6%
2494
September1st to 15thDay
27%6%10%18%23%13%
2340
16th to endDay
24%5%10%29%26%3
2174
October1st to 15thDay
32%8%12%26%16%2
1873
16th to endDay
26%8%17%29%15%2
1908
November1st to 15thDay
29%9%17%23%16%2
1718
16th to endDay
28%8%21%29%10%
1589
December1st to 15thDay
39%15%22%16%5%
1560
16th to endDay
43%16%13%18%6%1
1664
January1st to 15thNight
30%18%20%19%9%2
2716
16th to endNight
31%12%19%23%11%2
2720
February1st to 15thNight
40%17%19%15%6%
2483
16th to endNight
36%11%19%20%10%2
2073
March1st to 15thNight
25%11%20%26%14%1
2233
16th to endNight
31%9%19%28%8%1
2232
April1st to 15thNight
32%10%19%20%14%2
1948
16th to endNight
32%10%15%26%14%
1929
May1st to 15thNight
35%10%14%26%11%
1670
16th to endNight
26%11%18%27%13%1
1626
June1st to 15thNight
16%6%18%24%26%8%
1560
16th to endNight
12%49%23%30%19%
1560
July1st to 15thNight
19%8%18%18%20%13%
1480
16th to endNight
18%8%19%22%18%11%
1606
August1st to 15thNight
21%7%17%24%15%12%
1719
16th to endNight
20%8%14%22%26%8%
2058
September1st to 15thNight
21%5%14%21%24%13%
1950
16th to endNight
19%410%31%28%5%
2113
October1st to 15thNight
28%8%11%27%18%5%
2256
16th to endNight
22%7%16%33%16%3
2304
November1st to 15thNight
25%9%16%26%18%2
2469
16th to endNight
25%9%20%30%13%1
2698
December1st to 15thNight
35%15%22%18%8%
2730
16th to endNight
40%15%17%19%5%1
2912

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 15thDay
229%32%21%12%
135
16th to endDay
224%39%27%6%
144
February1st to 15thDay
8%45%31%15%
135
16th to endDay
243%30%21%2
120
March1st to 15thDay
6%32%38%17%6%
239
16th to endDay
5%40%38%12%2
352
April1st to 15thDay
8%39%33%16%2
329
16th to endDay
14%30%31%16%42
318
May1st to 15thDay
10%19%32%22%12%2
461
16th to endDay
11%13%28%26%17%2
597
June1st to 15thDay
5%10%31%27%21%3
570
16th to endDay
28%32%32%21%2
570
July1st to 15thDay
8%321%31%29%5%
550
16th to endDay
8%321%35%24%5%
525
August1st to 15thDay
8%5%36%34%12%3
359
16th to endDay
7%7%24%38%17%5%
396
September1st to 15thDay
8%13%29%29%13%5%
375
16th to endDay
5%14%40%25%12%2
274
October1st to 15thDay
8%20%35%24%8%2
157
16th to endDay
6%26%36%24%41
144
November1st to 15thDay
125%33%22%15%1
135
16th to endDay
7%33%49%8%1
135
December1st to 15thDay
5%36%38%15%3
135
16th to endDay
437%38%15%4
144
January1st to 15thNight
223%42%22%7%
975
16th to endNight
117%47%26%5%
848
February1st to 15thNight
322%44%23%5%
764
16th to endNight
221%50%22%3
684
March1st to 15thNight
214%44%28%9%
780
16th to endNight
412%47%26%7%
776
April1st to 15thNight
6%16%41%29%5%
584
16th to endNight
8%13%37%26%12%
579
May1st to 15thNight
11%6%33%31%16%
585
16th to endNight
6%5%26%37%22%1
611
June1st to 15thNight
36%25%41%22%
585
16th to endNight
2222%47%23%
585
July1st to 15thNight
4110%41%39%3
555
16th to endNight
16%43%43%3
612
August1st to 15thNight
49%46%36%1
575
16th to endNight
2112%41%38%3
621
September1st to 15thNight
5%117%45%26%3
585
16th to endNight
5%327%31%27%4
644
October1st to 15thNight
8%7%38%31%13%
752
16th to endNight
6%12%36%29%13%1
768
November1st to 15thNight
416%43%27%7%
949
16th to endNight
319%46%24%5%
975
December1st to 15thNight
5%21%48%21%3
975
16th to endNight
323%46%21%4
1040
Page generated at 2018-10-09 08:39:15. Version ac04

Copyright 2018 A. Danko


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