K&P at Clyde Forks
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the K&P at Clyde Forks clear sky chart from 2005-11-05 to 2017-09-20.

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
27%
14687
13%
46894
7%
14658
34%
14658
16%
33480

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
13%
720
6%
2506
2%
716
18%
716
6%
2035
January16th to endNight
17%
768
11%
2605
5%
768
25%
768
10%
1974
February1st to 15thNight
13%
701
9%
2287
3%
701
22%
701
10%
1746
February16th to endNight
17%
631
14%
1973
5%
631
29%
631
13%
1428
March1st to 15thNight
16%
720
12%
2067
5%
720
24%
720
14%
1538
March16th to endNight
28%
768
20%
2057
8%
768
37%
768
22%
1402
April1st to 15thNight
20%
718
15%
1796
5%
718
26%
718
18%
1323
April16th to endNight
28%
649
18%
1729
8%
649
35%
649
21%
1220
May1st to 15thNight
31%
360
18%
1440
15%
360
42%
360
16%
939
May16th to endNight
33%
375
14%
1497
10%
374
46%
374
19%
936
June1st to 15thNight
32%
360
9%
1440
6%
360
43%
360
14%
958
June16th to endNight
41%
360
9%
1440
10%
360
47%
360
17%
928
July1st to 15thNight
47%
340
14%
1360
19%
340
54%
340
26%
768
July16th to endNight
52%
376
14%
1418
14%
354
57%
354
26%
808
August1st to 15thNight
48%
485
14%
1556
10%
483
53%
483
25%
987
August16th to endNight
48%
687
21%
1833
9%
687
54%
687
36%
1135
September1st to 15thNight
41%
720
16%
1800
7%
720
45%
720
29%
1240
September16th to endNight
45%
677
21%
1855
14%
677
50%
677
30%
1199
October1st to 15thNight
30%
660
17%
1980
10%
660
39%
660
19%
1385
October16th to endNight
21%
704
10%
2172
4%
704
29%
704
11%
1681
November1st to 15thNight
25%
700
18%
2355
13%
700
33%
700
15%
1678
November16th to endNight
18%
720
11%
2520
7%
720
25%
720
9%
1948
December1st to 15thNight
15%
720
7%
2520
3%
720
20%
720
7%
2040
December16th to endNight
10%
768
9%
2688
4%
768
18%
768
7%
2184

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
17%9%36%6%3445%6%31%
47951
Night
16%9%46%6%34446%33%
47064
Cloud CoverDay
17%9%36%6%3445%6%31%
47961
Night
16%9%46%5%34446%33%
47069
TransparencyDay
52%6%11%18%10%1
47639
Night
51%6%11%19%9%
46894
SeeingDay
23%14%29%20%9%3
5448
Night
22%14%30%22%8%
14690

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
18%15%6%9%7%3434421%
1432
16th to endDay
14%14%5%10%9%46%335%21%
1617
February1st to 15thDay
13%13%5%12%8%35%435%22%
1575
16th to endDay
17%14%5%7%7%4444426%
1500
March1st to 15thDay
16%12%5%9%8%35%33426%
1880
16th to endDay
13%9%46%5%24435%39%
2166
April1st to 15thDay
21%12%35%5%2343433%
2152
16th to endDay
21%8%34424345%37%
2241
May1st to 15thDay
19%8%37%5%23445%33%
2511
16th to endDay
16%7%35%6%35%45%6%35%
2618
June1st to 15thDay
22%7%36%5%25%45%7%30%
2520
16th to endDay
16%5%26%5%45%5%5%7%32%
2520
July1st to 15thDay
12%6%346%35%5%6%9%36%
2520
16th to endDay
12%5%35%5%36%6%8%8%34%
2654
August1st to 15thDay
12%7%36%6%345%6%6%36%
2394
16th to endDay
14%4246%35%5%6%7%37%
2356
September1st to 15thDay
17%5%25%5%34347%40%
2160
16th to endDay
15%6%25%42335%7%43%
1870
October1st to 15thDay
23%8%346%34346%31%
1650
16th to endDay
26%9%48%6%3444424%
1699
November1st to 15thDay
14%10%36%6%3445%7%33%
1500
16th to endDay
21%13%6%7%5%34435%24%
1440
December1st to 15thDay
20%17%6%10%7%3433418%
1440
16th to endDay
22%16%6%7%5%2445%420%
1536
January1st to 15thNight
17%12%6%10%9%36%5%45%18%
2506
16th to endNight
13%13%6%8%7%35%446%25%
2605
February1st to 15thNight
13%14%7%10%7%34445%23%
2285
16th to endNight
13%12%47%7%3445%5%30%
1973
March1st to 15thNight
16%13%5%7%6%33335%30%
2055
16th to endNight
13%8%45%5%24345%40%
2057
April1st to 15thNight
20%9%45%433435%34%
1796
16th to endNight
17%8%26%5%24445%38%
1729
May1st to 15thNight
20%7%35%424345%38%
1440
16th to endNight
14%6%25%425%5%5%9%38%
1495
June1st to 15thNight
17%6%36%5%345%5%5%35%
1440
16th to endNight
14%6%25%435%5%6%8%37%
1440
July1st to 15thNight
9%325%435%5%5%7%47%
1440
16th to endNight
10%2145%35%5%6%8%46%
1514
August1st to 15thNight
8%5%25%5%35%6%5%7%43%
1566
16th to endNight
9%423424448%50%
1833
September1st to 15thNight
16%6%2443345%5%44%
1800
16th to endNight
15%5%14413445%48%
1855
October1st to 15thNight
20%8%35%5%2445%6%34%
1980
16th to endNight
24%11%36%6%3335%6%25%
2172
November1st to 15thNight
16%10%46%5%35%445%33%
2355
16th to endNight
21%13%47%6%24445%24%
2520
December1st to 15thNight
19%16%5%9%6%24445%20%
2520
16th to endNight
22%14%6%9%6%34435%19%
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
18%17%5%9%7%4344421%
1432
16th to endDay
14%15%5%10%8%5%5%44422%
1617
February1st to 15thDay
13%14%5%11%8%45%445%22%
1575
16th to endDay
17%15%47%7%3444426%
1500
March1st to 15thDay
16%12%5%9%8%45%33426%
1891
16th to endDay
13%9%47%424445%40%
2165
April1st to 15thDay
22%11%445%2334433%
2152
16th to endDay
21%8%25%42443437%
2241
May1st to 15thDay
19%9%36%5%2345%5%33%
2511
16th to endDay
16%6%36%6%35%5%5%6%35%
2618
June1st to 15thDay
22%7%36%4245%5%7%30%
2520
16th to endDay
16%5%26%6%46%5%5%8%32%
2520
July1st to 15thDay
12%6%25%5%35%5%6%9%36%
2520
16th to endDay
12%5%35%5%36%6%7%9%34%
2654
August1st to 15thDay
12%7%27%6%35%5%7%6%35%
2394
16th to endDay
14%4246%36%5%6%8%37%
2356
September1st to 15thDay
16%5%15%5%34447%41%
2160
16th to endDay
15%6%25%42435%7%42%
1870
October1st to 15thDay
22%8%35%5%44347%31%
1650
16th to endDay
27%9%38%6%35%43424%
1699
November1st to 15thDay
14%10%26%6%35%446%33%
1500
16th to endDay
22%13%5%7%5%34435%23%
1440
December1st to 15thDay
20%16%6%10%6%3434418%
1440
16th to endDay
22%16%6%7%5%24445%20%
1536
January1st to 15thNight
17%12%6%10%10%36%5%4418%
2506
16th to endNight
13%14%6%8%7%34445%25%
2605
February1st to 15thNight
13%14%6%10%7%3445%5%23%
2278
16th to endNight
13%12%47%8%3445%5%30%
1973
March1st to 15thNight
17%12%48%5%34335%30%
2067
16th to endNight
13%8%45%5%23445%40%
2057
April1st to 15thNight
20%9%45%5%23445%35%
1796
16th to endNight
17%8%25%5%23446%37%
1729
May1st to 15thNight
20%7%35%42435%5%38%
1440
16th to endNight
14%6%25%435%5%48%38%
1495
June1st to 15thNight
17%6%46%5%245%5%5%35%
1440
16th to endNight
14%6%34436%5%5%8%36%
1440
July1st to 15thNight
9%325%435%45%7%47%
1440
16th to endNight
9%3146%25%5%6%8%45%
1514
August1st to 15thNight
8%5%25%6%346%5%7%43%
1566
16th to endNight
9%424424448%50%
1833
September1st to 15thNight
15%5%25%42445%5%44%
1800
16th to endNight
16%5%25%32245%448%
1855
October1st to 15thNight
21%7%35%42445%6%34%
1980
16th to endNight
23%11%46%6%24346%25%
2172
November1st to 15thNight
16%10%36%5%35%445%33%
2355
16th to endNight
22%13%47%5%3445%424%
2520
December1st to 15thNight
19%16%5%9%6%34445%20%
2520
16th to endNight
22%14%6%9%6%34335%19%
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
64%6%9%11%6%1
1433
16th to endDay
65%5%7%11%8%1
1617
February1st to 15thDay
64%5%10%14%4
1577
16th to endDay
61%6%9%11%10%1
1500
March1st to 15thDay
62%410%15%7%
1891
16th to endDay
46%48%19%14%5%
2166
April1st to 15thDay
54%47%17%13%2
2152
16th to endDay
49%47%18%16%3
2241
May1st to 15thDay
50%5%9%17%14%2
2511
16th to endDay
47%6%11%19%12%1
2622
June1st to 15thDay
53%7%10%19%9%
2520
16th to endDay
48%7%11%19%11%
2520
July1st to 15thDay
39%7%13%27%11%
2371
16th to endDay
44%8%14%22%9%
2487
August1st to 15thDay
46%8%13%21%9%
2380
16th to endDay
41%7%16%24%9%
2356
September1st to 15thDay
42%6%13%25%11%
2160
16th to endDay
41%6%11%29%10%
1870
October1st to 15thDay
54%5%9%20%9%
1650
16th to endDay
64%6%10%14%4
1699
November1st to 15thDay
50%7%14%19%8%
1500
16th to endDay
62%7%9%12%6%1
1440
December1st to 15thDay
69%6%10%11%2
1440
16th to endDay
66%6%11%10%5%
1536
January1st to 15thNight
66%7%10%10%4
2506
16th to endNight
59%6%9%15%8%
2605
February1st to 15thNight
61%412%15%5%
2287
16th to endNight
54%5%11%18%10%
1973
March1st to 15thNight
56%411%18%7%
2067
16th to endNight
44%411%20%15%3
2057
April1st to 15thNight
51%5%8%19%14%1
1796
16th to endNight
47%5%6%20%17%2
1729
May1st to 15thNight
48%47%20%15%3
1440
16th to endNight
41%8%12%20%14%2
1497
June1st to 15thNight
48%6%12%20%10%1
1440
16th to endNight
43%8%12%20%13%
1440
July1st to 15thNight
33%7%12%28%16%1
1360
16th to endNight
34%7%16%26%14%
1418
August1st to 15thNight
36%10%16%23%11%
1556
16th to endNight
32%5%16%32%11%
1833
September1st to 15thNight
40%7%12%27%11%
1800
16th to endNight
37%5%12%34%8%
1855
October1st to 15thNight
49%5%11%20%12%
1980
16th to endNight
59%6%12%14%6%
2172
November1st to 15thNight
51%7%12%16%11%
2355
16th to endNight
61%6%10%16%3
2520
December1st to 15thNight
65%6%12%11%3
2520
16th to endNight
67%5%8%10%5%
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
30%30%15%21%3
60
16th to endDay
40%12%33%10%2
77
February1st to 15thDay
33%25%35%32
90
16th to endDay
31%23%30%10%3
159
March1st to 15thDay
27%18%33%16%4
270
16th to endDay
25%20%29%15%7%1
288
April1st to 15thDay
26%25%26%12%7%
270
16th to endDay
26%18%26%14%10%2
270
May1st to 15thDay
29%13%27%19%6%4
288
16th to endDay
23%15%33%18%7%2
331
June1st to 15thDay
27%12%27%21%9%
315
16th to endDay
16%13%33%23%12%1
315
July1st to 15thDay
14%6%31%30%12%4
305
16th to endDay
15%7%32%26%13%4
326
August1st to 15thDay
14%5%31%31%8%7%
313
16th to endDay
15%7%27%26%13%9%
332
September1st to 15thDay
17%8%27%21%13%11%
315
16th to endDay
17%8%29%21%13%8%
270
October1st to 15thDay
25%14%26%22%8%2
255
16th to endDay
32%17%31%14%4
261
November1st to 15thDay
21%11%33%22%8%1
154
16th to endDay
36%11%33%11%5%1
60
December1st to 15thDay
18%36%28%11%5%
60
16th to endDay
37%32%26%3
64
January1st to 15thNight
24%21%34%15%4
720
16th to endNight
21%18%35%19%4
768
February1st to 15thNight
22%19%38%16%2
704
16th to endNight
22%20%36%16%4
631
March1st to 15thNight
27%17%33%19%2
720
16th to endNight
19%18%28%23%8%
768
April1st to 15thNight
27%19%30%19%4
718
16th to endNight
23%17%27%24%7%
649
May1st to 15thNight
24%8%29%26%8%1
360
16th to endNight
16%8%37%25%11%
375
June1st to 15thNight
17%11%31%28%9%
360
16th to endNight
19%7%29%30%12%
360
July1st to 15thNight
8%6%31%37%15%1
340
16th to endNight
10%230%42%14%1
376
August1st to 15thNight
11%425%38%18%1
485
16th to endNight
11%430%31%19%2
687
September1st to 15thNight
20%6%27%25%17%2
720
16th to endNight
17%9%24%27%20%2
677
October1st to 15thNight
25%11%28%23%10%1
660
16th to endNight
29%16%27%20%6%
704
November1st to 15thNight
23%14%32%19%9%
700
16th to endNight
31%18%25%16%6%
720
December1st to 15thNight
27%20%31%16%2
720
16th to endNight
34%14%31%15%2
768
Page generated at 2017-09-21 07:18:18. Version ac04

Copyright 2017 A. Danko


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