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 2018-02-14.

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%
15425
15%
48585
7%
15386
35%
15386
18%
32967

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%
779
8%
2661
2%
776
17%
776
8%
2024
January16th to endNight
13%
832
12%
2704
3%
832
23%
832
9%
2036
February1st to 15thNight
10%
757
11%
2468
2%
757
20%
757
10%
1827
February16th to endNight
14%
631
12%
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
40%
540
24%
1041
May1st to 15thNight
38%
510
17%
1590
11%
510
45%
510
24%
1043
May16th to endNight
39%
374
17%
1497
13%
374
53%
374
26%
813
June1st to 15thNight
37%
360
13%
1440
10%
360
49%
360
22%
829
June16th to endNight
44%
360
15%
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
55%
478
33%
867
August1st to 15thNight
54%
539
17%
1609
11%
536
59%
536
37%
903
August16th to endNight
50%
609
23%
1755
12%
609
57%
609
35%
1041
September1st to 15thNight
48%
720
21%
1832
9%
720
54%
720
36%
1155
September16th to endNight
50%
717
23%
1990
15%
717
55%
717
33%
1201
October1st to 15thNight
31%
720
17%
2160
11%
720
39%
720
22%
1436
October16th to endNight
17%
768
14%
2304
5%
768
28%
768
14%
1662
November1st to 15thNight
28%
760
17%
2580
12%
760
36%
760
17%
1735
November16th to endNight
19%
780
11%
2730
5%
780
28%
780
11%
1967
December1st to 15thNight
10%
780
6%
2730
1%
780
16%
780
8%
2100
December16th to endNight
8%
832
7%
2912
1%
832
15%
832
6%
2308

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%
49479
Night
14%8%47%6%35%45%6%33%
48763
Cloud CoverDay
14%9%47%6%35%5%5%7%30%
49489
Night
14%8%36%6%35%5%5%7%34%
48767
TransparencyDay
51%412%20%9%
49176
Night
48%413%21%10%1
48585
SeeingDay
18%15%30%20%10%4
6014
Night
18%16%31%22%9%1
15430

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
15%15%7%12%7%35%5%35%16%
1606
16th to endDay
11%17%8%11%11%45%346%15%
1872
February1st to 15thDay
14%15%7%13%9%5%5%346%15%
1695
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%36%7%45%5%5%8%34%
2340
16th to endDay
12%6%36%6%46%5%6%8%33%
2435
September1st to 15thDay
14%8%36%5%2446%7%35%
2127
16th to endDay
15%7%36%5%2445%7%37%
1969
October1st to 15thDay
20%9%37%6%34445%31%
1800
16th to endDay
25%14%46%5%3445%5%20%
1920
November1st to 15thDay
15%12%47%5%345%47%27%
1606
16th to endDay
16%15%6%9%6%35%447%20%
1560
December1st to 15thDay
14%19%8%11%8%34345%15%
1560
16th to endDay
19%16%9%10%7%35%5%5%5%11%
1664
January1st to 15thNight
18%13%5%9%9%45%5%45%18%
2661
16th to endNight
11%12%6%12%9%46%5%5%7%18%
2704
February1st to 15thNight
12%12%5%10%8%35%5%5%7%22%
2466
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%413425%6%6%8%49%
1620
16th to endNight
8%425%434446%51%
1755
September1st to 15thNight
12%41442446%6%48%
1832
16th to endNight
12%5%1442335%7%47%
1990
October1st to 15thNight
17%5%36%5%24446%37%
2160
16th to endNight
19%9%47%6%345%5%6%27%
2304
November1st to 15thNight
16%9%35%6%345%5%7%32%
2580
16th to endNight
17%10%5%8%6%35%45%7%24%
2730
December1st to 15thNight
18%15%5%8%7%45%5%46%17%
2730
16th to endNight
19%13%8%11%8%345%46%13%
2912

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%13%7%11%7%35%6%46%17%
1606
16th to endDay
10%16%8%11%9%5%4447%16%
1872
February1st to 15thDay
14%15%6%11%10%45%5%35%18%
1695
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%
2340
16th to endDay
12%5%26%6%46%6%6%8%34%
2435
September1st to 15thDay
13%7%26%6%345%5%8%36%
2127
16th to endDay
15%5%27%6%3445%8%37%
1969
October1st to 15thDay
19%8%37%6%34445%32%
1800
16th to endDay
24%12%5%6%5%3445%6%21%
1920
November1st to 15thDay
14%11%37%5%345%6%8%28%
1606
16th to endDay
16%12%6%9%6%345%47%22%
1560
December1st to 15thDay
14%17%7%11%7%45%35%5%16%
1560
16th to endDay
19%14%7%9%7%35%6%5%5%13%
1664
January1st to 15thNight
18%12%5%8%7%45%5%5%5%20%
2661
16th to endNight
11%10%7%9%9%46%5%5%7%20%
2704
February1st to 15thNight
11%11%5%10%8%35%5%5%7%24%
2459
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%
1620
16th to endNight
9%4245%25%447%51%
1755
September1st to 15thNight
11%4244245%6%6%48%
1832
16th to endNight
12%42442345%7%48%
1990
October1st to 15thNight
17%6%26%5%24446%38%
2160
16th to endNight
18%9%47%6%345%5%7%28%
2304
November1st to 15thNight
15%8%35%6%35%5%5%7%33%
2580
16th to endNight
17%11%46%6%25%5%5%8%25%
2730
December1st to 15thNight
18%13%48%6%45%5%5%6%19%
2730
16th to endNight
19%13%8%9%7%45%5%46%15%
2912

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%411%12%5%
1607
16th to endDay
67%49%12%5%
1872
February1st to 15thDay
67%211%14%3
1697
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
2327
16th to endDay
44%414%25%9%
2435
September1st to 15thDay
44%413%25%9%1
2127
16th to endDay
44%411%28%10%
1969
October1st to 15thDay
53%310%20%10%1
1800
16th to endDay
61%414%13%5%
1920
November1st to 15thDay
51%5%14%19%7%
1606
16th to endDay
60%414%14%4
1560
December1st to 15thDay
68%412%12%3
1560
16th to endDay
68%5%10%11%2
1664
January1st to 15thNight
62%312%13%6%
2661
16th to endNight
60%413%15%4
2704
February1st to 15thNight
57%5%12%19%5%
2468
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%19%30%13%1
1609
16th to endNight
32%411%31%18%1
1755
September1st to 15thNight
33%5%14%30%14%1
1832
16th to endNight
35%313%33%13%
1990
October1st to 15thNight
45%411%24%13%
2160
16th to endNight
53%415%19%7%
2304
November1st to 15thNight
48%414%20%10%1
2580
16th to endNight
54%5%16%18%4
2730
December1st to 15thNight
62%415%13%3
2730
16th to endNight
67%312%12%4
2912

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
17%34%31%14%1
103
16th to endDay
34%28%27%9%
144
February1st to 15thDay
24%42%26%5%
130
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%426%28%20%9%
313
16th to endDay
14%6%22%26%20%11%
332
September1st to 15thDay
13%427%24%18%12%
315
16th to endDay
17%7%20%21%20%12%
314
October1st to 15thDay
22%13%29%15%12%4
315
16th to endDay
29%20%27%17%4
336
November1st to 15thDay
17%20%36%19%41
116
16th to endDay
21%27%41%7%2
90
December1st to 15thDay
26%38%27%6%
90
16th to endDay
31%36%27%41
96
January1st to 15thNight
25%26%33%11%2
780
16th to endNight
16%21%38%18%5%
832
February1st to 15thNight
20%28%34%13%3
760
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%324%39%21%2
539
16th to endNight
11%426%28%25%3
609
September1st to 15thNight
13%7%27%26%20%5%
720
16th to endNight
15%7%20%29%19%6%
717
October1st to 15thNight
21%11%30%20%13%2
720
16th to endNight
24%20%31%18%3
768
November1st to 15thNight
21%16%29%22%9%1
760
16th to endNight
24%23%28%18%5%
780
December1st to 15thNight
27%26%30%13%2
780
16th to endNight
27%25%30%13%2
832
Page generated at 2018-02-15 10:58:44. Version ac04

Copyright 2018 A. Danko


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