Cooksburg
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cooksburg 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
31%
15052
13%
46922
9%
15012
36%
15012
16%
34137

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
9%
717
7%
2401
3%
716
14%
716
5%
2023
January16th to endNight
11%
768
7%
2496
2%
768
17%
768
7%
2080
February1st to 15thNight
11%
704
7%
2287
3%
701
17%
701
7%
1924
February16th to endNight
13%
631
10%
1971
3%
631
21%
631
9%
1571
March1st to 15thNight
18%
720
14%
1980
7%
720
25%
720
13%
1565
March16th to endNight
21%
768
17%
2112
8%
768
29%
768
18%
1521
April1st to 15thNight
22%
718
13%
1823
4%
718
27%
718
18%
1373
April16th to endNight
31%
613
18%
1693
7%
613
38%
613
26%
1146
May1st to 15thNight
33%
540
14%
1620
8%
540
40%
540
19%
1149
May16th to endNight
47%
385
17%
1508
16%
385
54%
385
21%
935
June1st to 15thNight
50%
360
15%
1440
16%
360
58%
360
21%
885
June16th to endNight
46%
360
15%
1440
15%
360
54%
360
21%
893
July1st to 15thNight
52%
347
14%
1367
16%
347
56%
347
23%
810
July16th to endNight
65%
564
16%
1595
14%
531
67%
531
32%
962
August1st to 15thNight
62%
539
19%
1609
16%
536
64%
536
33%
964
August16th to endNight
63%
657
21%
1803
15%
657
66%
657
35%
1117
September1st to 15thNight
51%
720
20%
1809
13%
720
53%
720
31%
1203
September16th to endNight
47%
669
21%
1873
17%
669
51%
669
27%
1256
October1st to 15thNight
42%
660
17%
1980
15%
660
48%
660
24%
1312
October16th to endNight
25%
704
12%
2112
6%
704
34%
704
15%
1582
November1st to 15thNight
32%
700
18%
2275
13%
700
40%
700
19%
1540
November16th to endNight
19%
720
11%
2520
8%
720
25%
720
9%
1959
December1st to 15thNight
14%
720
6%
2520
4%
720
17%
720
6%
2096
December16th to endNight
10%
768
5%
2688
1%
768
15%
768
5%
2271

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
18%10%47%5%3445%6%28%
47866
Night
17%10%47%5%3445%6%31%
47105
Cloud CoverDay
18%10%47%5%3445%6%28%
47876
Night
16%10%47%5%34446%31%
47109
TransparencyDay
55%5%10%17%9%
47567
Night
53%5%11%17%10%1
46922
SeeingDay
24%12%25%20%12%5%
5453
Night
23%13%27%23%10%1
15056

By Month

Percentage Cloud Cover NE (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
20%15%8%14%6%2332417%
1534
16th to endDay
17%17%9%13%10%3433412%
1728
February1st to 15thDay
17%20%7%11%8%35%33314%
1575
16th to endDay
17%16%5%11%7%3434421%
1500
March1st to 15thDay
19%13%6%8%6%24445%23%
1969
16th to endDay
18%11%6%6%43435%5%29%
2112
April1st to 15thDay
22%12%46%5%34336%28%
2125
16th to endDay
22%9%25%333345%36%
2277
May1st to 15thDay
20%9%36%6%2445%6%28%
2331
16th to endDay
16%6%25%5%35%5%6%7%34%
2606
June1st to 15thDay
17%7%26%5%3445%8%33%
2520
16th to endDay
17%6%25%6%35%6%6%9%30%
2520
July1st to 15thDay
13%6%36%5%35%6%6%8%33%
2510
16th to endDay
13%6%35%6%5%7%5%6%8%31%
2465
August1st to 15thDay
12%6%36%5%46%5%6%9%30%
2340
16th to endDay
13%6%35%5%35%6%7%8%35%
2386
September1st to 15thDay
18%8%36%5%3445%5%35%
2149
16th to endDay
18%7%36%433348%34%
1812
October1st to 15thDay
23%7%35%5%3335%5%34%
1650
16th to endDay
24%11%37%5%245%45%26%
1760
November1st to 15thDay
13%10%45%5%235%5%7%35%
1581
16th to endDay
23%17%36%5%2443423%
1440
December1st to 15thDay
21%22%9%8%5%2333314%
1440
16th to endDay
23%18%9%11%6%2334411%
1536
January1st to 15thNight
21%17%7%12%6%3433316%
2401
16th to endNight
15%19%7%10%7%45%445%15%
2496
February1st to 15thNight
16%16%6%11%8%46%43318%
2285
16th to endNight
18%12%6%11%8%34435%22%
1971
March1st to 15thNight
18%12%5%7%7%3445%5%24%
1968
16th to endNight
17%10%46%424347%34%
2112
April1st to 15thNight
21%10%35%5%2345%6%31%
1823
16th to endNight
14%8%3441445%8%39%
1693
May1st to 15thNight
19%6%36%42445%6%35%
1620
16th to endNight
12%6%245%3445%8%41%
1506
June1st to 15thNight
10%6%25%4245%5%8%42%
1440
16th to endNight
12%5%36%5%3446%8%39%
1440
July1st to 15thNight
9%5%245%3446%7%43%
1447
16th to endNight
11%3234246%7%8%45%
1703
August1st to 15thNight
9%415%43447%9%46%
1620
16th to endNight
10%4133245%6%8%48%
1803
September1st to 15thNight
14%6%15%423446%45%
1809
16th to endNight
16%5%25%5%2435%6%41%
1873
October1st to 15thNight
18%5%25%423446%40%
1980
16th to endNight
25%10%25%42445%5%28%
2112
November1st to 15thNight
17%10%245%3445%6%36%
2275
16th to endNight
21%15%5%6%5%34346%22%
2520
December1st to 15thNight
21%17%9%8%6%2434416%
2520
16th to endNight
21%16%8%9%7%34345%14%
2688

Percentage Cloud Cover SE (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
20%15%7%14%7%3332318%
1534
16th to endDay
16%18%8%12%10%4433412%
1728
February1st to 15thDay
17%19%7%11%9%35%24314%
1575
16th to endDay
17%15%6%11%6%35%345%21%
1500
March1st to 15thDay
19%13%6%8%6%2344423%
1980
16th to endDay
18%11%5%7%43435%6%29%
2111
April1st to 15thDay
21%12%46%433335%28%
2125
16th to endDay
21%9%34433445%36%
2277
May1st to 15thDay
20%9%36%5%25%45%6%28%
2331
16th to endDay
16%6%35%5%35%46%7%34%
2606
June1st to 15thDay
17%6%26%6%3445%8%33%
2520
16th to endDay
17%6%25%6%35%6%6%9%29%
2520
July1st to 15thDay
12%6%37%6%36%6%6%8%32%
2510
16th to endDay
13%6%36%6%47%5%6%8%31%
2465
August1st to 15thDay
12%6%37%5%5%6%6%6%8%30%
2340
16th to endDay
14%5%25%5%35%7%6%7%34%
2386
September1st to 15thDay
18%8%36%5%3445%5%35%
2149
16th to endDay
18%6%36%5%3445%6%35%
1812
October1st to 15thDay
23%7%35%5%33345%34%
1650
16th to endDay
24%10%47%5%245%35%26%
1760
November1st to 15thDay
13%9%46%5%245%47%35%
1581
16th to endDay
23%17%46%5%2434422%
1440
December1st to 15thDay
20%23%9%9%5%2333315%
1440
16th to endDay
23%17%10%11%6%2333411%
1536
January1st to 15thNight
21%17%7%12%7%3333316%
2401
16th to endNight
14%19%8%9%7%45%5%45%15%
2496
February1st to 15thNight
16%15%7%11%8%5%7%33318%
2278
16th to endNight
17%12%5%11%7%44335%22%
1971
March1st to 15thNight
18%12%5%8%6%34445%24%
1980
16th to endNight
16%10%5%6%5%25%347%34%
2112
April1st to 15thNight
20%10%36%5%23446%30%
1823
16th to endNight
14%8%3442445%8%40%
1693
May1st to 15thNight
19%6%26%43445%7%34%
1619
16th to endNight
12%7%245%345%5%8%40%
1506
June1st to 15thNight
10%6%35%425%5%6%8%42%
1440
16th to endNight
12%5%36%5%3446%9%38%
1440
July1st to 15thNight
10%5%25%5%35%45%7%43%
1447
16th to endNight
11%3234246%7%9%45%
1703
August1st to 15thNight
9%415%43347%8%47%
1620
16th to endNight
10%3234245%5%8%48%
1803
September1st to 15thNight
14%5%24424446%46%
1809
16th to endNight
16%5%25%5%2445%6%41%
1873
October1st to 15thNight
18%6%25%433347%40%
1980
16th to endNight
25%9%25%43445%5%27%
2112
November1st to 15thNight
16%10%245%34446%36%
2275
16th to endNight
21%15%5%7%5%3435%5%22%
2520
December1st to 15thNight
21%17%9%8%6%3434415%
2520
16th to endNight
21%16%8%10%7%34345%14%
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
71%48%9%4
1535
16th to endDay
76%39%7%2
1728
February1st to 15thDay
75%46%9%3
1577
16th to endDay
65%411%13%5%
1500
March1st to 15thDay
62%5%11%15%5%
1980
16th to endDay
55%49%20%8%1
2112
April1st to 15thDay
57%49%16%10%
2125
16th to endDay
50%48%18%15%2
2277
May1st to 15thDay
54%5%10%19%9%
2331
16th to endDay
46%7%15%17%11%1
2610
June1st to 15thDay
48%6%11%21%11%
2520
16th to endDay
48%7%13%20%9%
2520
July1st to 15thDay
47%7%9%20%12%2
2361
16th to endDay
47%7%12%20%11%
2310
August1st to 15thDay
48%8%12%21%8%
2327
16th to endDay
43%7%12%21%12%2
2386
September1st to 15thDay
49%6%8%20%14%1
2149
16th to endDay
48%5%9%20%15%
1812
October1st to 15thDay
52%412%17%12%
1650
16th to endDay
59%5%13%16%5%
1760
November1st to 15thDay
47%5%12%17%13%3
1581
16th to endDay
64%48%14%6%
1440
December1st to 15thDay
74%310%8%2
1440
16th to endDay
76%5%7%8%1
1536
January1st to 15thNight
73%47%9%4
2401
16th to endNight
69%5%10%9%3
2496
February1st to 15thNight
71%5%7%11%4
2287
16th to endNight
64%5%8%15%6%
1971
March1st to 15thNight
61%5%7%17%7%
1980
16th to endNight
51%410%19%12%1
2112
April1st to 15thNight
54%5%9%18%12%
1823
16th to endNight
42%6%10%21%15%3
1693
May1st to 15thNight
48%6%11%19%12%1
1620
16th to endNight
40%7%14%20%14%2
1508
June1st to 15thNight
38%8%12%25%14%
1440
16th to endNight
40%7%13%20%15%1
1440
July1st to 15thNight
38%6%12%21%19%1
1367
16th to endNight
32%7%15%23%18%2
1595
August1st to 15thNight
32%7%15%28%15%
1609
16th to endNight
31%8%13%28%15%3
1803
September1st to 15thNight
39%5%12%22%17%2
1809
16th to endNight
42%5%8%25%16%1
1873
October1st to 15thNight
43%5%14%19%15%1
1980
16th to endNight
56%5%14%16%6%
2112
November1st to 15thNight
48%5%12%17%12%4
2275
16th to endNight
62%5%8%15%6%
2520
December1st to 15thNight
71%5%9%9%3
2520
16th to endNight
73%5%10%9%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
32%36%22%35%
77
16th to endDay
41%29%23%41
96
February1st to 15thDay
32%40%25%2
90
16th to endDay
26%20%45%7%
120
March1st to 15thDay
32%18%29%14%4
270
16th to endDay
27%20%29%13%6%1
288
April1st to 15thDay
33%17%23%16%8%1
270
16th to endDay
22%12%30%18%9%5%
270
May1st to 15thDay
32%14%21%18%9%2
288
16th to endDay
20%10%26%22%12%7%
331
June1st to 15thDay
21%9%27%26%12%1
315
16th to endDay
25%11%25%20%12%3
315
July1st to 15thDay
18%6%28%24%14%7%
305
16th to endDay
13%5%24%24%24%7%
326
August1st to 15thDay
18%222%23%23%10%
313
16th to endDay
15%320%27%17%15%
332
September1st to 15thDay
19%6%18%24%19%12%
315
16th to endDay
20%6%19%23%19%10%
262
October1st to 15thDay
23%8%21%28%14%2
255
16th to endDay
30%12%33%16%6%
272
November1st to 15thDay
21%8%26%23%16%3
159
16th to endDay
26%25%30%11%5%1
60
December1st to 15thDay
48%20%13%8%5%5%
60
16th to endDay
39%25%31%4
64
January1st to 15thNight
32%23%31%10%2
720
16th to endNight
24%26%32%15%1
768
February1st to 15thNight
27%22%33%14%1
704
16th to endNight
25%23%35%14%1
631
March1st to 15thNight
28%19%31%17%3
720
16th to endNight
22%16%35%18%6%
768
April1st to 15thNight
27%15%32%18%5%
718
16th to endNight
18%10%35%25%8%1
613
May1st to 15thNight
22%9%26%30%10%
540
16th to endNight
12%6%27%31%18%2
386
June1st to 15thNight
12%5%27%40%13%
360
16th to endNight
13%330%37%14%
360
July1st to 15thNight
12%123%40%18%2
347
16th to endNight
12%313%41%27%2
564
August1st to 15thNight
11%15%42%26%2
539
16th to endNight
11%216%35%29%4
657
September1st to 15thNight
18%5%17%30%23%3
720
16th to endNight
18%6%20%23%25%5%
669
October1st to 15thNight
22%8%21%29%16%1
660
16th to endNight
31%11%27%23%4
704
November1st to 15thNight
21%12%29%27%8%1
700
16th to endNight
32%18%25%15%7%
720
December1st to 15thNight
33%21%26%14%3
720
16th to endNight
30%22%31%13%2
768
Page generated at 2017-09-19 07:32:23. Version ac04

Copyright 2017 A. Danko


Cooksburg Clear Sky Chart | Charts Home