Forks of the Credit
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Forks of the Credit clear sky chart from 2005-11-05 to 2017-08-12.

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
27%
14694
15%
46271
7%
14655
36%
14655
18%
31432

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%
719
9%
2455
1%
716
17%
716
7%
1887
January16th to endNight
13%
768
13%
2496
4%
768
24%
768
9%
1886
February1st to 15thNight
10%
701
11%
2287
2%
701
21%
701
10%
1691
February16th to endNight
13%
631
13%
2006
3%
631
24%
631
11%
1455
March1st to 15thNight
18%
720
14%
1985
6%
720
26%
720
16%
1441
March16th to endNight
24%
768
21%
2112
8%
768
35%
768
23%
1422
April1st to 15thNight
21%
718
15%
1832
4%
718
28%
718
21%
1324
April16th to endNight
29%
540
20%
1620
7%
540
39%
540
24%
1041
May1st to 15thNight
38%
510
18%
1590
11%
510
46%
510
24%
1043
May16th to endNight
39%
374
17%
1497
13%
374
53%
374
26%
813
June1st to 15thNight
38%
360
13%
1440
10%
360
51%
360
22%
829
June16th to endNight
44%
360
16%
1261
14%
360
53%
360
30%
707
July1st to 15thNight
52%
340
18%
1265
20%
340
59%
340
36%
630
July16th to endNight
49%
511
16%
1542
11%
478
56%
478
33%
867
August1st to 15thNight
54%
527
18%
1575
11%
524
59%
524
37%
882
August16th to endNight
50%
558
22%
1608
12%
558
56%
558
35%
959
September1st to 15thNight
46%
660
22%
1679
9%
660
53%
660
35%
1068
September16th to endNight
48%
657
21%
1824
13%
657
54%
657
33%
1112
October1st to 15thNight
31%
660
19%
1980
11%
660
40%
660
22%
1315
October16th to endNight
17%
704
13%
2112
4%
704
28%
704
14%
1537
November1st to 15thNight
28%
700
18%
2377
13%
700
36%
700
17%
1578
November16th to endNight
20%
720
12%
2520
6%
720
29%
720
12%
1838
December1st to 15thNight
11%
720
7%
2520
2%
720
17%
720
8%
1946
December16th to endNight
8%
768
7%
2688
2%
768
15%
768
6%
2161

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
15%10%47%6%3445%7%29%
47689
Night
14%8%47%6%35%45%6%33%
46449
Cloud CoverDay
14%9%47%6%35%5%5%7%30%
47699
Night
14%8%36%6%35%5%5%7%34%
46453
TransparencyDay
51%412%20%9%
47386
Night
48%413%21%10%1
46271
SeeingDay
18%14%30%20%10%4
5439
Night
18%15%31%22%9%1
14699

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
16%15%7%12%7%35%5%35%16%
1482
16th to endDay
11%17%8%11%11%45%346%14%
1728
February1st to 15thDay
13%15%7%14%9%5%4346%16%
1575
16th to endDay
16%15%5%9%6%36%45%6%21%
1464
March1st to 15thDay
14%12%6%9%7%34445%27%
1963
16th to endDay
14%11%47%6%24436%32%
2112
April1st to 15thDay
19%11%37%5%23446%29%
2124
16th to endDay
18%9%35%423345%38%
2340
May1st to 15thDay
17%8%36%434346%34%
2358
16th to endDay
12%6%25%5%35%5%6%7%38%
2618
June1st to 15thDay
15%6%25%5%345%5%9%35%
2520
16th to endDay
13%5%25%5%345%7%10%35%
2694
July1st to 15thDay
9%5%36%5%45%5%7%9%37%
2616
16th to endDay
11%6%36%6%36%5%6%9%33%
2516
August1st to 15thDay
8%8%37%7%45%5%5%8%34%
2288
16th to endDay
12%6%36%5%46%5%6%8%33%
2231
September1st to 15thDay
15%8%36%6%2446%8%33%
1950
16th to endDay
16%7%36%5%2445%8%35%
1805
October1st to 15thDay
19%9%37%6%34445%31%
1650
16th to endDay
26%14%46%5%34445%19%
1760
November1st to 15thDay
14%12%47%5%345%47%29%
1479
16th to endDay
16%15%6%9%6%35%347%19%
1440
December1st to 15thDay
15%20%7%11%8%34345%14%
1440
16th to endDay
20%16%9%10%7%25%45%5%11%
1536
January1st to 15thNight
18%13%5%10%9%445%4417%
2455
16th to endNight
11%12%6%12%9%5%6%5%5%7%17%
2496
February1st to 15thNight
13%12%5%10%8%35%5%5%7%22%
2285
16th to endNight
12%11%6%10%7%35%45%7%24%
2006
March1st to 15thNight
16%9%47%6%35%45%6%29%
1973
16th to endNight
13%8%46%435%345%41%
2112
April1st to 15thNight
18%9%345%35%346%34%
1832
16th to endNight
11%8%26%6%24447%40%
1620
May1st to 15thNight
14%6%25%5%36%45%6%38%
1590
16th to endNight
11%5%25%324447%49%
1495
June1st to 15thNight
11%426%6%35%5%5%7%41%
1440
16th to endNight
9%425%5%2346%7%48%
1261
July1st to 15thNight
5%4245%24348%55%
1341
16th to endNight
8%2245%35%5%5%8%48%
1649
August1st to 15thNight
6%4134245%6%8%50%
1586
16th to endNight
9%425%434446%50%
1608
September1st to 15thNight
12%4245%2445%6%47%
1679
16th to endNight
13%6%1432335%7%46%
1824
October1st to 15thNight
16%6%37%5%2445%6%37%
1980
16th to endNight
19%10%47%6%3445%6%26%
2112
November1st to 15thNight
15%8%35%6%345%5%7%33%
2377
16th to endNight
18%10%5%8%6%35%45%7%23%
2520
December1st to 15thNight
18%15%5%8%7%45%5%45%17%
2520
16th to endNight
20%13%8%12%8%345%46%12%
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
15%14%7%11%7%35%5%46%17%
1482
16th to endDay
10%16%9%11%9%5%4447%16%
1728
February1st to 15thDay
13%15%6%12%10%445%35%18%
1575
16th to endDay
16%14%5%9%7%35%45%5%23%
1464
March1st to 15thDay
14%11%5%10%7%34445%27%
1974
16th to endDay
13%10%47%6%34446%33%
2111
April1st to 15thDay
18%10%46%5%2335%7%31%
2124
16th to endDay
17%9%36%423346%38%
2340
May1st to 15thDay
17%7%36%5%45%445%35%
2358
16th to endDay
11%6%35%5%45%5%5%8%38%
2618
June1st to 15thDay
15%6%25%5%345%6%9%36%
2520
16th to endDay
12%5%25%6%35%6%6%10%36%
2694
July1st to 15thDay
9%426%5%46%5%6%9%38%
2616
16th to endDay
10%6%27%6%36%5%7%9%34%
2516
August1st to 15thDay
8%6%26%6%47%5%7%8%35%
2288
16th to endDay
12%5%26%6%46%6%6%9%34%
2231
September1st to 15thDay
14%7%36%6%345%5%8%34%
1950
16th to endDay
16%6%27%6%3445%7%36%
1805
October1st to 15thDay
18%8%36%6%34445%32%
1650
16th to endDay
25%12%5%6%5%3345%6%20%
1760
November1st to 15thDay
13%11%47%5%345%6%8%29%
1479
16th to endDay
17%12%7%9%6%345%5%7%21%
1440
December1st to 15thDay
15%17%7%11%7%45%35%5%15%
1440
16th to endDay
20%15%8%9%7%35%6%45%13%
1536
January1st to 15thNight
18%13%5%8%7%45%5%5%5%19%
2455
16th to endNight
11%11%7%10%9%5%6%5%5%7%20%
2496
February1st to 15thNight
12%11%410%8%35%5%5%7%24%
2278
16th to endNight
12%10%6%10%7%44447%26%
2006
March1st to 15thNight
17%8%47%6%45%5%45%31%
1985
16th to endNight
13%8%36%5%34335%42%
2112
April1st to 15thNight
17%9%345%35%446%34%
1832
16th to endNight
11%7%35%6%345%47%41%
1620
May1st to 15thNight
14%5%245%36%45%7%40%
1589
16th to endNight
12%42432435%7%49%
1495
June1st to 15thNight
11%425%5%345%6%7%42%
1440
16th to endNight
9%42443445%7%48%
1261
July1st to 15thNight
5%3145%2345%7%56%
1341
16th to endNight
8%2145%345%6%8%49%
1649
August1st to 15thNight
6%3144245%7%7%51%
1586
16th to endNight
9%4245%25%447%50%
1608
September1st to 15thNight
12%42442446%6%47%
1679
16th to endNight
13%5%2442345%7%47%
1824
October1st to 15thNight
17%6%26%5%24446%38%
1980
16th to endNight
19%9%37%6%3445%7%27%
2112
November1st to 15thNight
15%8%35%6%35%5%5%7%34%
2377
16th to endNight
18%11%46%7%26%5%5%8%24%
2520
December1st to 15thNight
19%13%48%6%45%5%5%6%18%
2520
16th to endNight
19%13%8%10%7%45%5%46%13%
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
66%311%12%5%
1483
16th to endDay
68%49%12%5%
1728
February1st to 15thDay
67%211%14%3
1577
16th to endDay
60%213%14%7%1
1464
March1st to 15thDay
57%412%17%8%
1974
16th to endDay
51%39%19%13%1
2112
April1st to 15thDay
53%310%20%11%
2124
16th to endDay
47%211%21%14%1
2340
May1st to 15thDay
49%410%22%11%
2358
16th to endDay
42%415%21%14%1
2622
June1st to 15thDay
43%413%25%12%
2520
16th to endDay
41%5%15%24%12%
2694
July1st to 15thDay
39%5%12%24%15%1
2464
16th to endDay
44%5%13%24%10%2
2360
August1st to 15thDay
43%416%20%12%1
2275
16th to endDay
44%414%26%9%1
2231
September1st to 15thDay
46%413%25%8%
1950
16th to endDay
46%412%26%10%
1805
October1st to 15thDay
53%311%20%10%1
1650
16th to endDay
63%414%13%4
1760
November1st to 15thDay
51%5%15%19%8%
1479
16th to endDay
62%413%14%4
1440
December1st to 15thDay
69%312%11%2
1440
16th to endDay
69%5%11%10%2
1536
January1st to 15thNight
63%312%13%5%
2455
16th to endNight
60%413%16%4
2496
February1st to 15thNight
57%5%12%20%5%
2287
16th to endNight
56%314%17%7%
2006
March1st to 15thNight
53%313%21%7%
1985
16th to endNight
45%39%22%16%2
2112
April1st to 15thNight
49%410%20%14%
1832
16th to endNight
42%310%21%18%2
1620
May1st to 15thNight
43%49%25%15%1
1590
16th to endNight
34%415%27%14%3
1497
June1st to 15thNight
37%5%12%25%17%1
1440
16th to endNight
34%414%29%16%
1261
July1st to 15thNight
26%412%29%23%2
1265
16th to endNight
31%5%16%27%15%2
1542
August1st to 15thNight
28%5%20%30%13%1
1575
16th to endNight
33%411%30%18%1
1608
September1st to 15thNight
34%414%31%13%
1679
16th to endNight
36%314%32%12%
1824
October1st to 15thNight
45%411%24%13%
1980
16th to endNight
54%415%18%7%
2112
November1st to 15thNight
47%414%21%11%1
2377
16th to endNight
56%415%18%4
2520
December1st to 15thNight
62%416%12%3
2520
16th to endNight
68%312%11%2
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
15%34%34%11%2
69
16th to endDay
36%25%30%8%
96
February1st to 15thDay
21%43%27%6%1
90
16th to endDay
27%28%39%4
81
March1st to 15thDay
21%23%31%18%5%
264
16th to endDay
21%16%35%17%7%1
288
April1st to 15thDay
22%18%32%16%7%1
270
16th to endDay
21%20%31%14%8%4
270
May1st to 15thDay
20%14%30%19%10%5%
288
16th to endDay
14%12%33%22%11%3
331
June1st to 15thDay
17%12%34%22%11%1
315
16th to endDay
15%13%35%23%10%2
489
July1st to 15thDay
10%7%33%28%14%6%
398
16th to endDay
9%7%31%27%16%6%
326
August1st to 15thDay
10%5%26%27%20%10%
297
16th to endDay
13%322%26%22%11%
268
September1st to 15thDay
13%426%26%15%12%
255
16th to endDay
20%6%22%24%15%11%
254
October1st to 15thDay
20%14%30%16%13%3
255
16th to endDay
31%19%26%17%4
272
November1st to 15thDay
11%20%41%20%32
79
16th to endDay
23%26%36%10%3
60
December1st to 15thDay
26%40%25%8%
60
16th to endDay
34%40%23%1
64
January1st to 15thNight
26%26%33%10%2
720
16th to endNight
16%20%38%19%5%
768
February1st to 15thNight
20%26%35%13%3
704
16th to endNight
19%22%37%16%3
631
March1st to 15thNight
23%20%33%19%3
720
16th to endNight
17%17%35%19%8%
768
April1st to 15thNight
22%17%34%20%3
718
16th to endNight
15%13%36%25%8%1
540
May1st to 15thNight
15%10%29%30%11%2
510
16th to endNight
14%8%33%28%14%
375
June1st to 15thNight
13%8%31%32%13%
360
16th to endNight
9%5%35%36%13%
360
July1st to 15thNight
5%5%30%37%19%1
340
16th to endNight
9%332%35%18%1
511
August1st to 15thNight
7%325%38%22%2
527
16th to endNight
11%426%28%25%3
558
September1st to 15thNight
14%7%27%26%19%5%
660
16th to endNight
16%7%22%31%18%4
657
October1st to 15thNight
20%11%30%20%13%2
660
16th to endNight
25%20%31%18%3
704
November1st to 15thNight
20%16%30%22%9%1
700
16th to endNight
24%21%28%18%5%
720
December1st to 15thNight
27%25%30%13%2
720
16th to endNight
27%24%30%13%2
768
Page generated at 2017-08-13 14:16:47. Version ac04

Copyright 2017 A. Danko


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