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 2017-09-18.

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
42%
15985
20%
46883
12%
15943
50%
15943
32%
28138

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
27%
899
15%
2506
8%
895
34%
895
23%
1706
January16th to endNight
29%
783
20%
2511
11%
783
41%
783
25%
1568
February1st to 15thNight
23%
696
9%
2288
4%
696
30%
696
16%
1595
February16th to endNight
20%
632
16%
1915
4%
632
34%
632
22%
1259
March1st to 15thNight
32%
720
19%
2061
8%
720
43%
720
31%
1250
March16th to endNight
31%
716
19%
2060
10%
716
40%
716
30%
1278
April1st to 15thNight
34%
539
15%
1798
9%
539
43%
539
26%
1076
April16th to endNight
36%
540
18%
1800
14%
540
44%
540
25%
1096
May1st to 15thNight
43%
540
17%
1542
11%
540
49%
540
27%
995
May16th to endNight
55%
563
18%
1498
12%
561
59%
561
34%
919
June1st to 15thNight
60%
540
20%
1440
13%
540
65%
540
50%
758
June16th to endNight
70%
540
29%
1440
22%
540
74%
540
63%
695
July1st to 15thNight
77%
510
19%
1360
16%
510
78%
510
47%
746
July16th to endNight
83%
564
22%
1473
20%
531
83%
531
47%
793
August1st to 15thNight
77%
539
21%
1611
20%
536
78%
536
43%
845
August16th to endNight
78%
573
30%
1899
31%
573
82%
573
44%
950
September1st to 15thNight
68%
540
29%
1800
27%
540
76%
540
44%
896
September16th to endNight
63%
553
33%
1817
30%
553
68%
553
48%
869
October1st to 15thNight
43%
660
25%
1980
15%
660
52%
660
34%
1163
October16th to endNight
42%
704
28%
2112
13%
704
54%
704
39%
1133
November1st to 15thNight
33%
874
23%
2274
10%
874
42%
874
38%
1376
November16th to endNight
29%
900
23%
2490
8%
900
41%
900
34%
1466
December1st to 15thNight
19%
900
10%
2520
3%
900
25%
900
21%
1750
December16th to endNight
20%
960
13%
2688
4%
960
28%
960
18%
1956

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%35%5%35%5%6%8%47%
47918
Night
242443445%8%54%
47060
TransparencyDay
33%10%15%20%14%4
47597
Night
28%10%17%24%14%4
46883
SeeingDay
7%16%31%26%14%2
5887
Night
412%35%30%15%1
15994

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%6%6%8%45%
1432
16th to endDay
438%7%3446%9%46%
1722
February1st to 15thDay
45%9%9%5%6%6%6%8%37%
1575
16th to endDay
46%9%7%47%6%6%9%38%
1557
March1st to 15thDay
5%35%6%35%6%5%9%48%
1896
16th to endDay
26%46%6%35%6%7%8%41%
2163
April1st to 15thDay
29%45%5%45%5%6%8%42%
2150
16th to endDay
310%47%6%46%5%5%9%35%
2160
May1st to 15thDay
7%8%35%5%35%5%6%7%40%
2405
16th to endDay
6%6%27%6%46%6%7%10%36%
2616
June1st to 15thDay
43134345%6%9%51%
2520
16th to endDay
1123235%5%6%66%
2520
July1st to 15thDay
43246%36%6%5%7%49%
2520
16th to endDay
5%4245%47%5%6%9%44%
2591
August1st to 15thDay
5%5%25%7%36%6%6%8%42%
2340
16th to endDay
44145%46%5%5%8%50%
2301
September1st to 15thDay
5%32442345%6%56%
2160
16th to endDay
5%5%14323345%61%
1865
October1st to 15thDay
45%245%345%5%5%52%
1650
16th to endDay
35%2432345%7%55%
1749
November1st to 15thDay
15%45%425%46%7%52%
1583
16th to endDay
1336%5%345%5%7%53%
1467
December1st to 15thDay
6%39%7%36%6%7%11%37%
1440
16th to endDay
6%310%7%47%5%6%8%38%
1536
January1st to 15thNight
3245%36%5%6%10%51%
2506
16th to endNight
226%6%345%6%9%51%
2511
February1st to 15thNight
327%8%47%6%6%9%42%
2277
16th to endNight
5%48%6%345%6%8%46%
1915
March1st to 15thNight
1325%42346%8%56%
2061
16th to endNight
25%35%435%5%5%9%51%
2060
April1st to 15thNight
26%25%426%5%5%8%50%
1798
16th to endNight
48%36%3245%6%6%49%
1800
May1st to 15thNight
6%7%245%245%5%8%46%
1541
16th to endNight
4413435%5%6%9%51%
1497
June1st to 15thNight
3112224449%64%
1440
16th to endNight
2121235%6%73%
1440
July1st to 15thNight
321232436%10%60%
1440
16th to endNight
2122325%46%8%60%
1574
August1st to 15thNight
2334245%6%9%56%
1620
16th to endNight
22343346%8%60%
1899
September1st to 15thNight
4312323448%62%
1800
16th to endNight
4212212236%68%
1817
October1st to 15thNight
45%1342346%6%56%
1980
16th to endNight
3413323337%61%
2112
November1st to 15thNight
232432335%9%58%
2274
16th to endNight
122443336%9%57%
2490
December1st to 15thNight
6%26%5%346%6%10%44%
2520
16th to endNight
1438%7%45%6%6%10%41%
2688

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
36%16%23%14%7%1
1433
16th to endDay
36%12%20%20%8%1
1722
February1st to 15thDay
45%14%18%14%7%
1575
16th to endDay
41%12%21%17%6%
1557
March1st to 15thDay
31%13%21%22%10%
1896
16th to endDay
36%13%16%22%8%1
2163
April1st to 15thDay
38%12%16%19%11%2
2150
16th to endDay
41%12%16%21%7%
2160
May1st to 15thDay
39%10%16%21%11%
2405
16th to endDay
38%10%15%22%10%1
2620
June1st to 15thDay
25%8%15%20%21%8%
2520
16th to endDay
16%5%9%21%32%14%
2520
July1st to 15thDay
29%9%12%15%18%13%
2371
16th to endDay
32%9%13%19%14%10%
2429
August1st to 15thDay
36%10%11%14%17%9%
2325
16th to endDay
29%8%12%21%20%7%
2301
September1st to 15thDay
26%6%11%19%23%12%
2160
16th to endDay
24%5%11%29%25%3
1865
October1st to 15thDay
32%7%13%28%15%3
1650
16th to endDay
26%8%17%30%14%1
1749
November1st to 15thDay
30%9%17%22%17%2
1583
16th to endDay
29%9%22%27%10%
1467
December1st to 15thDay
40%15%22%15%4
1440
16th to endDay
45%16%13%18%5%1
1536
January1st to 15thNight
30%18%20%19%8%2
2506
16th to endNight
32%12%18%23%11%1
2511
February1st to 15thNight
39%16%19%15%6%
2288
16th to endNight
37%11%18%20%10%2
1915
March1st to 15thNight
27%11%20%26%12%1
2061
16th to endNight
32%8%19%28%8%1
2060
April1st to 15thNight
31%10%19%21%15%2
1798
16th to endNight
33%10%16%26%12%
1800
May1st to 15thNight
35%11%14%26%12%
1542
16th to endNight
27%11%18%28%13%1
1498
June1st to 15thNight
17%7%19%24%24%6%
1440
16th to endNight
12%5%9%23%29%20%
1440
July1st to 15thNight
19%8%18%18%19%14%
1360
16th to endNight
19%8%19%20%18%12%
1473
August1st to 15thNight
21%7%18%23%15%13%
1611
16th to endNight
19%8%14%22%27%8%
1899
September1st to 15thNight
21%5%14%21%24%12%
1800
16th to endNight
19%5%10%32%28%4
1817
October1st to 15thNight
29%8%12%29%16%4
1980
16th to endNight
23%7%16%34%16%2
2112
November1st to 15thNight
25%9%17%25%18%3
2274
16th to endNight
25%9%20%30%12%1
2490
December1st to 15thNight
36%16%22%17%7%
2520
16th to endNight
41%16%17%18%5%1
2688

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
324%31%21%18%1
90
16th to endDay
319%35%35%6%
96
February1st to 15thDay
437%37%20%
90
16th to endDay
237%30%25%3
81
March1st to 15thDay
7%30%38%17%6%
186
16th to endDay
5%38%39%13%3
288
April1st to 15thDay
7%34%34%20%2
269
16th to endDay
15%30%32%16%21
270
May1st to 15thDay
11%19%32%22%11%2
392
16th to endDay
12%14%28%25%15%2
517
June1st to 15thDay
5%9%32%27%21%3
495
16th to endDay
17%31%32%23%2
495
July1st to 15thDay
8%321%32%28%4
475
16th to endDay
8%320%35%25%5%
450
August1st to 15thDay
10%336%35%12%2
315
16th to endDay
7%5%21%40%18%6%
332
September1st to 15thDay
8%14%30%28%12%4
315
16th to endDay
5%11%34%27%16%4
179
October1st to 15thDay
416%35%26%13%3
90
16th to endDay
8%20%38%25%5%2
96
November1st to 15thDay
14%33%26%23%2
90
16th to endDay
8%25%58%6%
90
December1st to 15thDay
7%41%37%12%1
90
16th to endDay
431%41%18%4
96
January1st to 15thNight
223%42%22%7%
900
16th to endNight
116%47%27%6%
783
February1st to 15thNight
319%46%24%6%
704
16th to endNight
220%50%21%4
632
March1st to 15thNight
314%44%27%9%
720
16th to endNight
5%12%47%26%8%
716
April1st to 15thNight
5%14%41%31%6%
539
16th to endNight
8%13%37%27%12%
540
May1st to 15thNight
10%6%35%30%16%
540
16th to endNight
6%5%27%36%22%1
563
June1st to 15thNight
46%26%40%22%
540
16th to endNight
1222%47%25%
540
July1st to 15thNight
4110%42%38%2
510
16th to endNight
26%42%44%3
564
August1st to 15thNight
310%46%37%1
539
16th to endNight
2111%41%40%3
573
September1st to 15thNight
6%118%44%25%3
540
16th to endNight
5%325%30%30%4
553
October1st to 15thNight
8%6%38%31%14%1
660
16th to endNight
6%11%37%29%13%1
704
November1st to 15thNight
415%43%27%8%
874
16th to endNight
319%45%25%6%
900
December1st to 15thNight
6%21%48%20%3
900
16th to endNight
322%46%22%5%
960
Page generated at 2017-09-19 05:32:22. Version ac04

Copyright 2017 A. Danko


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