Dedication Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dedication Point clear sky chart from 2005-11-05 to 2017-09-21.

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
55%
14826
21%
46870
17%
14802
60%
14802
31%
27772

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
42%
716
9%
2506
9%
716
45%
716
13%
1871
January16th to endNight
48%
768
11%
2688
10%
768
51%
768
18%
1862
February1st to 15thNight
50%
696
11%
2235
8%
696
54%
696
22%
1494
February16th to endNight
43%
632
17%
1895
14%
632
49%
632
22%
1302
March1st to 15thNight
43%
720
12%
2157
8%
720
49%
720
22%
1481
March16th to endNight
41%
768
18%
2037
11%
768
47%
768
26%
1371
April1st to 15thNight
48%
719
22%
1799
9%
719
54%
719
33%
1170
April16th to endNight
50%
581
27%
1661
16%
581
56%
581
36%
962
May1st to 15thNight
52%
539
24%
1619
16%
539
59%
539
42%
858
May16th to endNight
59%
385
20%
1507
23%
385
65%
385
29%
799
June1st to 15thNight
54%
360
17%
1440
20%
360
62%
360
30%
750
June16th to endNight
63%
360
27%
1440
34%
360
75%
360
46%
579
July1st to 15thNight
72%
340
24%
1360
31%
340
82%
340
53%
510
July16th to endNight
74%
376
34%
1416
42%
354
82%
354
62%
484
August1st to 15thNight
74%
485
33%
1558
27%
483
79%
483
55%
685
August16th to endNight
78%
709
39%
1855
24%
709
82%
709
69%
847
September1st to 15thNight
77%
720
36%
1847
23%
720
81%
720
67%
897
September16th to endNight
69%
680
34%
1881
28%
680
73%
680
48%
1014
October1st to 15thNight
61%
660
29%
1846
24%
660
66%
660
42%
1034
October16th to endNight
60%
704
26%
2288
24%
704
66%
704
34%
1280
November1st to 15thNight
56%
700
23%
2275
22%
700
62%
700
29%
1364
November16th to endNight
50%
720
16%
2352
11%
720
57%
720
25%
1501
December1st to 15thNight
49%
720
10%
2520
7%
720
53%
720
17%
1718
December16th to endNight
37%
768
13%
2688
10%
768
43%
768
16%
1939

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
7%5%2442445%7%52%
48006
Night
8%5%2442445%7%49%
47043
TransparencyDay
30%5%12%20%18%11%
47677
Night
34%6%12%21%16%9%
46871
SeeingDay
9%7%24%29%20%8%
5411
Night
10%421%34%23%3
14840

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
12%8%5%8%7%46%6%5%8%26%
1432
16th to endDay
11%8%410%10%46%448%24%
1536
February1st to 15thDay
9%7%5%7%7%35%6%6%7%35%
1623
16th to endDay
6%10%5%6%5%35%5%6%8%36%
1579
March1st to 15thDay
9%9%36%6%36%5%6%8%33%
1803
16th to endDay
10%7%35%6%35%6%5%8%36%
2184
April1st to 15thDay
8%5%35%5%35%5%7%9%40%
2149
16th to endDay
7%42442346%6%52%
2298
May1st to 15thDay
5%31342435%6%59%
2331
16th to endDay
7%5%2342446%8%49%
2603
June1st to 15thDay
7%424425%6%5%8%48%
2520
16th to endDay
221112346%72%
2520
July1st to 15thDay
222213245%71%
2520
16th to endDay
21211222477%
2657
August1st to 15thDay
222223345%69%
2394
16th to endDay
111111223476%
2345
September1st to 15thDay
121121223476%
2112
16th to endDay
6%313213345%63%
1871
October1st to 15thDay
7%413413347%56%
1780
16th to endDay
7%5%145%245%5%8%47%
1584
November1st to 15thDay
10%6%25%5%3445%9%42%
1584
16th to endDay
11%6%35%6%36%5%7%9%34%
1605
December1st to 15thDay
14%8%37%6%25%5%5%7%32%
1440
16th to endDay
16%10%38%9%45%45%6%25%
1536
January1st to 15thNight
10%10%410%8%36%5%5%7%28%
2506
16th to endNight
12%8%49%43445%7%34%
2688
February1st to 15thNight
12%7%25%435%5%6%7%39%
2224
16th to endNight
8%7%47%6%35%6%7%8%34%
1895
March1st to 15thNight
11%9%35%436%5%5%7%37%
2157
16th to endNight
11%8%245%25%46%7%40%
2037
April1st to 15thNight
8%5%24436%5%6%7%44%
1799
16th to endNight
8%31343445%7%52%
1661
May1st to 15thNight
3214334447%59%
1619
16th to endNight
5%2245%26%5%6%9%48%
1507
June1st to 15thNight
7%3232245%5%8%51%
1440
16th to endNight
321231335%6%67%
1440
July1st to 15thNight
12132335%6%70%
1440
16th to endNight
111212235%75%
1512
August1st to 15thNight
322213346%69%
1566
16th to endNight
111112245%76%
1855
September1st to 15thNight
112212245%75%
1847
16th to endNight
6%312324345%62%
1881
October1st to 15thNight
7%31432445%5%56%
1846
16th to endNight
8%5%135%25%45%7%50%
2288
November1st to 15thNight
12%6%1442446%7%45%
2275
16th to endNight
13%6%35%43445%7%41%
2352
December1st to 15thNight
14%8%36%6%35%45%7%35%
2520
16th to endNight
18%11%36%6%34446%31%
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
54%12%16%15%1
1432
16th to endDay
56%11%17%14%1
1536
February1st to 15thDay
44%9%19%19%5%
1623
16th to endDay
43%8%17%23%6%
1579
March1st to 15thDay
45%8%15%22%6%1
1803
16th to endDay
43%7%16%21%9%1
2184
April1st to 15thDay
38%6%16%22%14%1
2149
16th to endDay
30%5%12%27%19%4
2298
May1st to 15thDay
25%48%27%26%6%
2331
16th to endDay
29%6%14%26%18%5%
2607
June1st to 15thDay
31%6%11%21%22%6%
2520
16th to endDay
13%35%20%37%19%
2520
July1st to 15thDay
14%26%14%29%32%
2371
16th to endDay
12%146%26%49%
2490
August1st to 15thDay
16%36%13%26%32%
2377
16th to endDay
12%16%14%35%29%
2345
September1st to 15thDay
13%25%17%32%29%
2112
16th to endDay
23%37%25%29%10%
1871
October1st to 15thDay
27%5%13%29%19%5%
1780
16th to endDay
32%5%13%31%16%1
1584
November1st to 15thDay
38%6%17%26%9%
1584
16th to endDay
43%9%20%22%4
1605
December1st to 15thDay
48%10%21%15%3
1440
16th to endDay
56%6%17%15%3
1536
January1st to 15thNight
53%10%15%15%3
2506
16th to endNight
48%7%17%21%4
2688
February1st to 15thNight
41%9%21%20%5%
2235
16th to endNight
44%8%15%23%6%
1895
March1st to 15thNight
45%7%13%22%8%1
2157
16th to endNight
40%6%13%26%11%
2037
April1st to 15thNight
35%6%12%28%15%1
1799
16th to endNight
30%48%29%24%2
1661
May1st to 15thNight
23%5%10%21%34%4
1620
16th to endNight
29%7%10%28%16%7%
1507
June1st to 15thNight
29%6%11%22%24%5%
1440
16th to endNight
16%45%20%30%23%
1440
July1st to 15thNight
14%26%12%27%36%
1360
16th to endNight
10%147%25%50%
1416
August1st to 15thNight
16%36%13%23%37%
1558
16th to endNight
10%25%14%28%38%
1855
September1st to 15thNight
12%3413%31%34%
1847
16th to endNight
23%4420%28%18%
1881
October1st to 15thNight
27%49%26%24%7%
1846
16th to endNight
31%412%27%21%2
2288
November1st to 15thNight
36%5%13%26%15%1
2275
16th to endNight
41%5%17%26%8%
2352
December1st to 15thNight
47%8%22%17%4
2520
16th to endNight
53%7%16%19%4
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
16%6%15%26%23%11%
60
16th to endDay
20%421%23%20%9%
64
February1st to 15thDay
14%7%25%18%24%9%
185
16th to endDay
10%15%29%30%9%4
238
March1st to 15thDay
16%12%34%23%10%1
270
16th to endDay
16%13%35%27%5%1
288
April1st to 15thDay
8%16%31%21%14%8%
269
16th to endDay
9%16%33%24%12%3
270
May1st to 15thDay
6%11%28%32%15%4
288
16th to endDay
11%6%18%29%22%10%
330
June1st to 15thDay
7%10%25%32%16%7%
315
16th to endDay
16%24%37%22%8%
315
July1st to 15thDay
2223%33%25%11%
305
16th to endDay
221%40%26%8%
327
August1st to 15thDay
4126%31%27%8%
315
16th to endDay
3115%34%30%15%
332
September1st to 15thDay
4119%23%31%20%
315
16th to endDay
6%419%30%24%14%
276
October1st to 15thDay
10%6%25%26%23%8%
252
16th to endDay
23%220%28%19%5%
96
November1st to 15thDay
16%112%33%36%
90
16th to endDay
21%16%22%29%9%
87
December1st to 15thDay
30%10%20%31%5%3
60
16th to endDay
34%412%26%14%7%
64
January1st to 15thNight
12%5%23%33%20%4
720
16th to endNight
16%317%30%28%3
768
February1st to 15thNight
15%420%37%21%1
704
16th to endNight
10%6%30%32%18%1
632
March1st to 15thNight
15%6%27%30%17%2
720
16th to endNight
14%7%30%32%12%1
768
April1st to 15thNight
10%8%25%34%18%2
719
16th to endNight
9%8%27%34%16%3
581
May1st to 15thNight
48%28%32%22%2
540
16th to endNight
5%321%35%27%5%
386
June1st to 15thNight
9%6%24%34%21%3
360
16th to endNight
46%23%32%30%3
360
July1st to 15thNight
1217%45%31%2
340
16th to endNight
2119%43%32%2
376
August1st to 15thNight
4115%42%35%1
485
16th to endNight
2212%44%32%5%
709
September1st to 15thNight
2115%33%38%8%
720
16th to endNight
8%314%31%31%10%
680
October1st to 15thNight
7%321%33%27%6%
660
16th to endNight
10%318%35%24%6%
704
November1st to 15thNight
14%419%33%25%3
700
16th to endNight
15%423%33%19%3
720
December1st to 15thNight
16%419%39%18%2
720
16th to endNight
22%425%31%14%
768
Page generated at 2017-09-22 05:35:37. Version ac04

Copyright 2017 A. Danko


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