Knight Sight
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Knight Sight clear sky chart from 2005-11-05 to

2017-09-12
.

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
68%
15775
38%
46669
29%
15734
76%
15734
63%
20276

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
68%
716
30%
2468
29%
716
75%
716
49%
1101
January16th to endNight
64%
768
39%
2332
33%
768
74%
768
52%
1107
February1st to 15thNight
65%
698
35%
2107
31%
697
73%
697
54%
994
February16th to endNight
56%
632
35%
1895
30%
632
68%
632
48%
941
March1st to 15thNight
61%
720
33%
2160
29%
720
73%
720
55%
987
March16th to endNight
54%
768
37%
2025
21%
768
67%
768
61%
966
April1st to 15thNight
47%
719
35%
1799
12%
719
61%
719
59%
897
April16th to endNight
53%
720
40%
1800
15%
720
65%
720
72%
808
May1st to 15thNight
53%
564
38%
1643
21%
563
62%
563
72%
654
May16th to endNight
49%
561
36%
1685
20%
561
61%
561
70%
651
June1st to 15thNight
57%
506
36%
1586
25%
506
67%
506
77%
576
June16th to endNight
72%
360
42%
1440
43%
360
82%
360
83%
409
July1st to 15thNight
86%
340
37%
1360
40%
340
91%
340
67%
450
July16th to endNight
81%
588
35%
1615
28%
553
82%
553
63%
725
August1st to 15thNight
83%
717
39%
1790
23%
713
85%
713
84%
781
August16th to endNight
87%
764
46%
1910
29%
764
89%
764
80%
855
September1st to 15thNight
86%
706
42%
1816
31%
706
90%
706
78%
808
September16th to endNight
83%
656
48%
1815
40%
656
90%
656
84%
720
October1st to 15thNight
71%
660
43%
1815
33%
660
81%
660
68%
797
October16th to endNight
75%
704
45%
2157
41%
704
84%
704
69%
874
November1st to 15thNight
77%
700
39%
2275
40%
700
84%
700
65%
910
November16th to endNight
75%
720
40%
2340
40%
720
82%
720
61%
961
December1st to 15thNight
66%
720
35%
2340
32%
720
75%
720
51%
1075
December16th to endNight
60%
768
34%
2496
30%
768
69%
768
43%
1229

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
111212235%75%
47969
Night
111212235%75%
46861
TransparencyDay
12%25%15%26%36%
47656
Night
11%26%17%29%31%
46675
SeeingDay
310%22%31%23%9%
5831
Night
25%21%39%28%3
15787

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
3114323337%64%
1457
16th to endDay
4414323346%61%
1890
February1st to 15thDay
1112323347%68%
1751
16th to endDay
3213424347%62%
1579
March1st to 15thDay
11121245%9%68%
1800
16th to endDay
111121345%7%70%
2196
April1st to 15thDay
2111212237%73%
2149
16th to endDay
1111136%79%
2160
May1st to 15thDay
111125%82%
2307
16th to endDay
1111112482%
2429
June1st to 15thDay
1113484%
2370
16th to endDay
1111288%
2520
July1st to 15thDay
11121233476%
2520
16th to endDay
1112314345%71%
2436
August1st to 15thDay
111112482%
2160
16th to endDay
122222479%
2292
September1st to 15thDay
111233480%
2063
16th to endDay
1212286%
1815
October1st to 15thDay
111212335%76%
1815
16th to endDay
1111135%80%
1712
November1st to 15thDay
111112235%76%
1584
16th to endDay
312223337%70%
1620
December1st to 15thDay
221232435%9%61%
1620
16th to endDay
4324323446%60%
1724
January1st to 15thNight
2212313446%66%
2468
16th to endNight
3212223336%67%
2332
February1st to 15thNight
2212212347%68%
2101
16th to endNight
421232345%7%62%
1895
March1st to 15thNight
112313347%69%
2160
16th to endNight
11221235%8%71%
2025
April1st to 15thNight
1111112347%72%
1799
16th to endNight
1111135%82%
1800
May1st to 15thNight
112235%82%
1643
16th to endNight
111125%83%
1684
June1st to 15thNight
1122486%
1586
16th to endNight
11291%
1440
July1st to 15thNight
11111222381%
1440
16th to endNight
121221233475%
1724
August1st to 15thNight
11122385%
1800
16th to endNight
1112384%
1910
September1st to 15thNight
11122383%
1816
16th to endNight
1112288%
1815
October1st to 15thNight
11112245%78%
1815
16th to endNight
11111122381%
2157
November1st to 15thNight
11212235%77%
2275
16th to endNight
21212337%73%
2340
December1st to 15thNight
2212313348%65%
2340
16th to endNight
4213313346%63%
2496

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
19%29%23%28%15%
1457
16th to endDay
23%47%22%23%18%
1890
February1st to 15thDay
17%27%21%28%22%
1751
16th to endDay
21%37%22%30%12%
1579
March1st to 15thDay
12%28%25%29%21%
1800
16th to endDay
12%39%25%28%19%
2196
April1st to 15thDay
13%3421%34%22%
2149
16th to endDay
8%26%20%32%29%
2160
May1st to 15thDay
8%1419%31%35%
2307
16th to endDay
8%1415%37%31%
2432
June1st to 15thDay
6%1211%23%54%
2370
16th to endDay
5%11414%72%
2520
July1st to 15thDay
10%236%17%59%
2371
16th to endDay
15%2412%21%43%
2283
August1st to 15thDay
7%127%16%64%
2146
16th to endDay
10%126%24%55%
2292
September1st to 15thDay
9%138%21%54%
2063
16th to endDay
7%116%30%53%
1815
October1st to 15thDay
10%3313%32%35%
1815
16th to endDay
9%1414%28%41%
1712
November1st to 15thDay
12%26%17%37%24%
1584
16th to endDay
14%36%19%31%24%
1620
December1st to 15thDay
17%5%12%23%25%15%
1620
16th to endDay
23%7%10%26%20%12%
1724
January1st to 15thNight
18%38%19%30%19%
2468
16th to endNight
18%28%22%23%23%
2332
February1st to 15thNight
16%38%20%26%23%
2112
16th to endNight
19%48%23%28%15%
1895
March1st to 15thNight
14%38%24%26%21%
2160
16th to endNight
12%311%26%29%16%
2025
April1st to 15thNight
13%39%27%28%17%
1799
16th to endNight
6%17%28%32%22%
1800
May1st to 15thNight
6%26%22%35%26%
1644
16th to endNight
7%17%21%41%21%
1685
June1st to 15thNight
41415%28%45%
1586
16th to endNight
316%20%65%
1440
July1st to 15thNight
8%218%19%59%
1360
16th to endNight
13%25%11%24%41%
1615
August1st to 15thNight
5%127%28%55%
1790
16th to endNight
6%118%30%50%
1910
September1st to 15thNight
7%248%29%47%
1816
16th to endNight
41110%32%50%
1815
October1st to 15thNight
10%25%13%34%33%
1815
16th to endNight
9%25%11%28%43%
2157
November1st to 15thNight
11%25%16%35%29%
2275
16th to endNight
11%37%20%26%30%
2340
December1st to 15thNight
17%311%19%29%17%
2340
16th to endNight
21%411%22%25%13%
2496

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
9%12%20%38%15%4
65
16th to endDay
6%14%19%28%20%9%
258
February1st to 15thDay
113%24%28%21%10%
266
16th to endDay
5%21%22%26%17%6%
238
March1st to 15thDay
6%13%23%28%21%7%
270
16th to endDay
417%28%24%20%4
288
April1st to 15thDay
5%23%23%24%15%7%
269
16th to endDay
325%28%22%15%4
270
May1st to 15thDay
414%26%28%20%5%
288
16th to endDay
313%31%26%19%6%
330
June1st to 15thDay
111%30%29%19%7%
315
16th to endDay
429%32%21%10%
315
July1st to 15thDay
1217%38%26%13%
305
16th to endDay
312%40%26%16%
327
August1st to 15thDay
3122%34%26%12%
315
16th to endDay
1114%36%30%15%
332
September1st to 15thDay
219%40%26%11%
300
16th to endDay
15%16%36%30%10%
255
October1st to 15thDay
311%24%29%24%6%
255
16th to endDay
25%23%26%30%11%
205
November1st to 15thDay
17%13%21%32%24%
90
16th to endDay
116%12%33%34%2
90
December1st to 15thDay
15%18%40%25%8%
90
16th to endDay
8%12%13%37%25%2
95
January1st to 15thNight
2417%41%28%5%
720
16th to endNight
4421%38%27%2
768
February1st to 15thNight
3420%39%28%3
704
16th to endNight
48%28%36%18%3
632
March1st to 15thNight
18%24%39%22%2
720
16th to endNight
19%32%34%20%1
768
April1st to 15thNight
212%35%28%18%2
719
16th to endNight
11%32%33%18%2
720
May1st to 15thNight
7%37%38%15%1
564
16th to endNight
10%36%34%16%
563
June1st to 15thNight
6%35%45%12%
506
16th to endNight
26%56%15%
360
July1st to 15thNight
8%56%32%1
340
16th to endNight
210%55%31%1
588
August1st to 15thNight
112%47%34%4
717
16th to endNight
7%40%42%7%
764
September1st to 15thNight
19%36%45%6%
706
16th to endNight
212%35%42%6%
656
October1st to 15thNight
1421%36%33%2
660
16th to endNight
1217%32%37%7%
704
November1st to 15thNight
1214%41%33%6%
700
16th to endNight
2314%38%33%6%
720
December1st to 15thNight
3419%39%28%4
720
16th to endNight
5%7%21%41%22%2
768
Page generated at 2017-09-13 04:39:08. Version ac04

Copyright 2017 A. Danko


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