Knight Sight
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Knight Sight clear sky chart from 2005-11-06 to 2024-02-20.

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
65%
24414
38%
79040
29%
24331
75%
24331
59%
33375

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
61%
749
38%
4248
28%
736
70%
736
37%
1437
January11th to 20thNight
65%
750
39%
3957
34%
740
75%
740
38%
1495
January21st to endNight
59%
827
27%
3884
32%
814
71%
814
35%
1715
February1st to 10thNight
58%
760
37%
2280
29%
760
70%
760
50%
1106
February11th to 20thNight
58%
738
40%
2211
31%
738
72%
738
56%
1021
February21st to endNight
51%
592
37%
1776
28%
592
66%
592
50%
837
March1st to 10thNight
51%
720
32%
2160
24%
720
67%
720
50%
1032
March11th to 20thNight
56%
720
32%
2093
24%
720
67%
720
53%
982
March21st to endNight
45%
792
37%
2026
16%
792
62%
792
57%
1013
April1st to 10thNight
44%
720
36%
1800
13%
720
59%
720
57%
928
April11th to 20thNight
47%
711
40%
1779
14%
711
62%
711
66%
835
April21st to endNight
50%
720
40%
1800
14%
720
63%
720
70%
814
May1st to 10thNight
44%
576
40%
1656
18%
576
57%
576
70%
670
May11th to 20thNight
51%
531
41%
1595
21%
531
65%
531
68%
623
May21st to endNight
47%
582
37%
1746
19%
582
61%
582
72%
659
June1st to 10thNight
57%
540
37%
1620
23%
540
67%
540
79%
605
June11th to 20thNight
61%
399
43%
1479
34%
399
76%
399
82%
447
June21st to endNight
70%
360
43%
1440
42%
360
83%
360
80%
418
July1st to 10thNight
86%
350
42%
1400
44%
350
92%
350
77%
422
July11th to 20thNight
82%
429
37%
1473
35%
429
85%
429
63%
566
July21st to endNight
83%
633
39%
1714
30%
598
84%
598
66%
766
August1st to 10thNight
80%
716
39%
1780
24%
712
82%
712
81%
801
August11th to 20thNight
85%
712
42%
1780
24%
712
88%
712
85%
774
August21st to endNight
86%
792
46%
1980
30%
792
88%
792
81%
887
September1st to 10thNight
83%
720
44%
1800
30%
720
88%
720
78%
824
September11th to 20thNight
80%
720
49%
1969
37%
720
89%
720
87%
780
September21st to endNight
80%
720
48%
1980
39%
720
90%
720
84%
784
October1st to 10thNight
69%
720
43%
1980
30%
720
83%
720
70%
861
October11th to 20thNight
75%
720
49%
2034
40%
720
86%
720
76%
832
October21st to endNight
72%
792
45%
2484
40%
792
84%
792
72%
950
November1st to 10thNight
74%
740
41%
2405
39%
740
83%
740
70%
912
November11th to 20thNight
79%
760
42%
2470
41%
760
86%
760
67%
975
November21st to endNight
68%
760
40%
2470
37%
760
76%
760
56%
1062
December1st to 10thNight
64%
760
35%
2470
31%
760
73%
760
50%
1144
December11th to 20thNight
62%
759
33%
2911
32%
758
70%
758
41%
1334
December21st to endNight
55%
824
22%
4390
27%
817
66%
817
27%
2064

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
2212223346%74%
79121
Night
2212223346%74%
80075
TransparencyDay
12%36%16%27%36%
78839
Night
13%37%18%29%30%
79878
SeeingDay
39%20%29%26%12%
14533
Night
25%24%41%25%3
24463

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
2213323447%69%
2539
11th to 20thDay
431442346%9%61%
2839
21st to endDay
6%42443445%6%59%
3498
February1st to 10thDay
231342335%6%67%
1900
11th to 20thDay
3212323348%70%
1841
21st to endDay
2224324347%68%
1480
March1st to 10thDay
332332345%9%63%
1800
11th to 20thDay
221332345%8%66%
1866
21st to endDay
121121345%7%73%
2326
April1st to 10thDay
3112323337%72%
2160
11th to 20thDay
111221223481%
2129
21st to endDay
1111212247%78%
2160
May1st to 10thDay
111212235%81%
2304
11th to 20thDay
112112135%83%
2301
21st to endDay
111221223481%
2530
June1st to 10thDay
111112236%81%
2340
11th to 20thDay
1112391%
2473
21st to endDay
111221221385%
2520
July1st to 10thDay
11122232481%
2520
11th to 20thDay
121321234477%
2432
21st to endDay
2113324446%70%
2499
August1st to 10thDay
211121223481%
2149
11th to 20thDay
111212235%81%
2122
21st to endDay
111222233480%
2376
September1st to 10thDay
11221234480%
2160
11th to 20thDay
111222289%
1990
21st to endDay
11111223386%
1980
October1st to 10thDay
1111222335%79%
1980
11th to 20thDay
111223385%
1922
21st to endDay
111111126%84%
1871
November1st to 10thDay
12213335%79%
1674
11th to 20thDay
2212222445%75%
1710
21st to endDay
3112223347%71%
1710
December1st to 10thDay
3322325%45%8%62%
1710
11th to 20thDay
33244245%6%9%57%
2169
21st to endDay
4426%5%45%6%7%7%49%
3141
January1st to 10thNight
2213323446%71%
4384
11th to 20thNight
231332345%8%65%
4101
21st to endNight
432332446%7%62%
4180
February1st to 10thNight
4413322346%68%
2280
11th to 20thNight
321222336%6%69%
2211
21st to endNight
3213324447%68%
1776
March1st to 10thNight
221332445%8%65%
2160
11th to 20thNight
321332335%8%68%
2093
21st to endNight
221232435%7%70%
2026
April1st to 10thNight
221222445%7%70%
1800
11th to 20thNight
1111223346%78%
1779
21st to endNight
111112246%82%
1800
May1st to 10thNight
1112346%81%
1656
11th to 20thNight
11221235%83%
1594
21st to endNight
1111111225%85%
1746
June1st to 10thNight
1111235%85%
1620
11th to 20thNight
1122390%
1479
21st to endNight
11111112390%
1440
July1st to 10thNight
11111222387%
1440
11th to 20thNight
1212213325%77%
1521
21st to endNight
1213222335%76%
1815
August1st to 10thNight
2121223483%
1790
11th to 20thNight
11111222487%
1780
21st to endNight
11121223484%
1980
September1st to 10thNight
111111223384%
1800
11th to 20thNight
1111112290%
1969
21st to endNight
111122388%
1980
October1st to 10thNight
111211333480%
1980
11th to 20thNight
11121223385%
2034
21st to endNight
11111233484%
2484
November1st to 10thNight
1111212245%80%
2405
11th to 20thNight
1112212346%77%
2470
21st to endNight
3112323347%71%
2470
December1st to 10thNight
3313423448%65%
2470
11th to 20thNight
32134235%6%10%60%
3041
21st to endNight
3325%6%35%5%5%7%56%
4521

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
14%46%34%33%9%
2539
11th to 20thDay
20%5%17%25%22%10%
2839
21st to endDay
24%5%10%27%24%10%
3498
February1st to 10thDay
19%37%19%28%24%
1900
11th to 20thDay
14%27%20%33%24%
1851
21st to endDay
17%48%21%32%18%
1480
March1st to 10thDay
18%38%23%28%20%
1800
11th to 20thDay
15%48%22%29%22%
1866
21st to endDay
11%49%25%32%19%
2326
April1st to 10thDay
15%36%20%31%24%
2160
11th to 20thDay
9%2419%36%31%
2132
21st to endDay
8%27%18%35%29%
2160
May1st to 10thDay
8%25%19%30%35%
2304
11th to 20thDay
7%1415%37%35%
2304
21st to endDay
9%25%16%37%32%
2530
June1st to 10thDay
8%2313%26%48%
2340
11th to 20thDay
3129%21%65%
2473
21st to endDay
8%22315%70%
2520
July1st to 10thDay
7%235%15%68%
2451
11th to 20thDay
12%249%20%53%
2357
21st to endDay
14%36%12%24%40%
2360
August1st to 10thDay
9%226%14%66%
2135
11th to 20thDay
7%239%21%58%
2122
21st to endDay
10%135%21%59%
2376
September1st to 10thDay
10%248%16%61%
2160
11th to 20thDay
4126%27%59%
1990
21st to endDay
6%128%31%52%
1980
October1st to 10thDay
10%3312%28%44%
1980
11th to 20thDay
6%2311%30%48%
1922
21st to endDay
7%1312%28%49%
1871
November1st to 10thDay
10%15%16%38%30%
1674
11th to 20thDay
11%36%17%31%32%
1710
21st to endDay
14%37%16%33%27%
1710
December1st to 10thDay
19%5%9%21%23%22%
1710
11th to 20thDay
22%7%16%19%26%10%
2168
21st to endDay
28%9%10%25%19%8%
3141
January1st to 10thNight
16%48%23%39%11%
4384
11th to 20thNight
18%312%31%23%12%
4101
21st to endNight
22%412%26%25%12%
4180
February1st to 10thNight
19%47%18%26%26%
2280
11th to 20thNight
15%46%19%30%26%
2212
21st to endNight
17%48%22%27%22%
1776
March1st to 10thNight
17%5%8%24%27%19%
2160
11th to 20thNight
15%5%10%22%27%21%
2093
21st to endNight
14%410%27%31%14%
2026
April1st to 10thNight
15%410%25%25%21%
1800
11th to 20thNight
9%26%28%29%25%
1779
21st to endNight
7%28%24%40%19%
1800
May1st to 10thNight
6%37%23%34%26%
1656
11th to 20thNight
8%16%18%40%27%
1595
21st to endNight
6%17%24%42%20%
1746
June1st to 10thNight
5%15%18%31%40%
1620
11th to 20thNight
22312%27%54%
1479
21st to endNight
5%125%22%66%
1440
July1st to 10thNight
5%215%19%68%
1400
11th to 20thNight
11%3411%21%50%
1473
21st to endNight
13%25%13%30%37%
1714
August1st to 10thNight
7%228%24%57%
1780
11th to 20thNight
4237%28%55%
1780
21st to endNight
7%227%27%57%
1980
September1st to 10thNight
8%246%25%55%
1800
11th to 20thNight
4137%32%53%
1969
21st to endNight
41210%30%53%
1980
October1st to 10thNight
9%2412%29%44%
1980
11th to 20thNight
7%2410%32%45%
2034
21st to endNight
7%2410%25%51%
2484
November1st to 10thNight
9%26%15%35%33%
2405
11th to 20thNight
10%26%15%31%36%
2470
21st to endNight
15%37%19%26%30%
2470
December1st to 10thNight
19%39%19%27%23%
2470
11th to 20thNight
18%6%14%21%29%12%
3041
21st to endNight
25%8%11%26%22%9%
4521

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
49%23%33%26%6%
180
11th to 20thDay
8%11%17%28%26%10%
292
21st to endDay
5%14%22%27%26%6%
506
February1st to 10thDay
5%14%24%27%20%10%
460
11th to 20thDay
6%15%26%29%16%8%
452
21st to endDay
6%16%25%31%19%3
346
March1st to 10thDay
9%18%25%28%15%4
420
11th to 20thDay
7%17%26%26%19%5%
420
21st to endDay
5%20%29%28%14%4
462
April1st to 10thDay
8%13%28%24%20%8%
420
11th to 20thDay
421%28%25%16%6%
412
21st to endDay
417%27%23%17%12%
420
May1st to 10thDay
5%14%29%23%22%6%
423
11th to 20thDay
313%28%27%17%12%
448
21st to endDay
415%21%27%21%11%
485
June1st to 10thDay
39%24%27%27%11%
450
11th to 20thDay
8%22%30%24%16%
450
21st to endDay
1326%29%27%14%
450
July1st to 10thDay
1116%36%31%14%
446
11th to 20thDay
29%33%32%23%
444
21st to endDay
217%32%33%25%
487
August1st to 10thDay
3213%35%31%16%
447
11th to 20thDay
2111%28%32%25%
437
21st to endDay
112%31%35%20%
495
September1st to 10thDay
1117%29%32%20%
450
11th to 20thDay
1320%34%31%11%
450
21st to endDay
26%15%32%31%15%
450
October1st to 10thDay
27%20%29%30%12%
450
11th to 20thDay
16%15%32%32%14%
450
21st to endDay
25%19%27%34%13%
386
November1st to 10thDay
19%17%30%32%11%
270
11th to 20thDay
25%14%34%31%13%
270
21st to endDay
310%15%29%34%9%
270
December1st to 10thDay
4317%41%27%8%
270
11th to 20thDay
47%16%35%29%9%
270
21st to endDay
7%12%23%30%24%3
295
January1st to 10thNight
5%6%23%37%26%4
760
11th to 20thNight
4422%43%25%3
760
21st to endNight
5%6%25%42%21%2
836
February1st to 10thNight
5%8%23%38%23%4
760
11th to 20thNight
37%29%36%22%3
742
21st to endNight
5%11%30%38%14%2
592
March1st to 10thNight
210%33%37%17%2
720
11th to 20thNight
310%28%37%20%2
720
21st to endNight
212%39%32%14%1
792
April1st to 10thNight
310%40%27%17%3
720
11th to 20thNight
112%38%33%15%1
711
21st to endNight
113%35%31%18%2
720
May1st to 10thNight
10%44%33%12%1
576
11th to 20thNight
10%36%39%15%1
531
21st to endNight
211%38%37%12%
584
June1st to 10thNight
15%36%47%10%
540
11th to 20thNight
435%48%13%
399
21st to endNight
1126%58%14%
360
July1st to 10thNight
11%59%28%1
350
11th to 20thNight
310%64%23%
429
21st to endNight
210%62%24%1
633
August1st to 10thNight
215%53%28%2
716
11th to 20thNight
111%48%36%4
712
21st to endNight
110%44%40%6%
792
September1st to 10thNight
2111%39%42%5%
720
11th to 20thNight
1117%41%36%4
720
21st to endNight
315%39%38%5%
720
October1st to 10thNight
1423%38%31%2
720
11th to 20thNight
1318%37%37%4
720
21st to endNight
1421%33%33%9%
792
November1st to 10thNight
1320%39%32%6%
740
11th to 20thNight
1314%47%29%7%
760
21st to endNight
4321%40%30%3
760
December1st to 10thNight
4422%41%26%3
760
11th to 20thNight
5%6%22%41%24%3
760
21st to endNight
48%26%39%20%2
836
Page generated at 2024-02-17 03:28:37. Version ac07

Copyright 2024 Attilla Danko


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