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Carp Library / Diefenbunker
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carp Library / Diefenbunker clear sky chart from 2005-11-05 to 2018-01-12.

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
31%
15120
14%
48382
9%
15089
38%
15089
18%
33735

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
16%
765
7%
2662
3%
761
22%
761
8%
2116
January16th to endNight
22%
768
12%
2633
7%
768
30%
768
12%
1928
February1st to 15thNight
19%
703
11%
2287
5%
701
27%
701
12%
1714
February16th to endNight
24%
631
14%
1955
6%
631
34%
631
14%
1431
March1st to 15thNight
22%
720
14%
2091
8%
720
30%
720
16%
1551
March16th to endNight
32%
768
21%
2040
10%
768
40%
768
23%
1377
April1st to 15thNight
23%
718
16%
1796
6%
718
28%
718
20%
1304
April16th to endNight
32%
644
18%
1724
9%
644
37%
644
23%
1192
May1st to 15thNight
35%
360
18%
1440
17%
360
44%
360
18%
924
May16th to endNight
36%
375
14%
1497
11%
374
49%
374
20%
939
June1st to 15thNight
38%
360
10%
1440
9%
360
47%
360
17%
929
June16th to endNight
45%
360
9%
1440
12%
360
51%
360
20%
882
July1st to 15thNight
53%
340
16%
1360
21%
340
59%
340
29%
727
July16th to endNight
57%
376
15%
1418
18%
354
61%
354
28%
775
August1st to 15thNight
53%
452
16%
1523
14%
450
59%
450
28%
905
August16th to endNight
55%
703
22%
1849
11%
703
60%
703
38%
1128
September1st to 15thNight
47%
720
16%
1800
9%
720
50%
720
31%
1211
September16th to endNight
51%
717
25%
1962
16%
717
56%
717
33%
1234
October1st to 15thNight
36%
720
18%
2160
12%
720
45%
720
22%
1458
October16th to endNight
26%
768
13%
2394
7%
768
34%
768
14%
1766
November1st to 15thNight
29%
760
17%
2539
13%
760
37%
760
17%
1755
November16th to endNight
20%
780
11%
2730
7%
780
27%
780
10%
2058
December1st to 15thNight
18%
780
8%
2730
4%
780
24%
780
9%
2138
December16th to endNight
14%
832
11%
2912
4%
832
23%
832
9%
2293

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%8%36%5%35%45%6%33%
48964
Night
17%9%46%5%34446%32%
48551
Cloud CoverDay
21%7%35%5%34446%33%
48973
Night
20%8%36%5%24445%33%
48557
TransparencyDay
50%311%21%10%1
48651
Night
52%311%21%10%
48382
SeeingDay
21%10%27%22%12%4
5789
Night
22%9%27%28%10%
15121

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%13%5%9%7%35%345%20%
1520
16th to endDay
14%15%48%7%45%35%6%23%
1590
February1st to 15thDay
13%13%5%11%7%45%45%423%
1575
16th to endDay
17%13%48%7%25%445%27%
1517
March1st to 15thDay
17%10%46%8%36%5%4428%
1856
16th to endDay
15%8%35%424446%40%
2184
April1st to 15thDay
23%8%36%423345%34%
2152
16th to endDay
20%8%25%5%23445%37%
2244
May1st to 15thDay
19%7%36%5%35%346%33%
2511
16th to endDay
17%5%35%6%35%45%6%35%
2618
June1st to 15thDay
20%6%35%5%36%45%8%30%
2520
16th to endDay
16%6%35%5%35%6%6%7%32%
2520
July1st to 15thDay
12%5%245%36%6%6%8%39%
2520
16th to endDay
11%5%25%436%5%7%9%38%
2654
August1st to 15thDay
10%5%26%5%36%6%6%8%38%
2425
16th to endDay
10%5%25%435%5%6%8%41%
2339
September1st to 15thDay
15%5%25%5%25%447%41%
2160
16th to endDay
13%5%2442445%7%45%
1997
October1st to 15thDay
20%7%36%43445%6%34%
1800
16th to endDay
25%8%36%6%35%436%27%
1830
November1st to 15thDay
16%8%35%5%45%5%5%6%32%
1648
16th to endDay
22%10%47%7%35%445%24%
1560
December1st to 15thDay
19%15%48%8%45%5%46%17%
1560
16th to endDay
22%14%5%8%7%1433422%
1664
January1st to 15thNight
17%14%6%11%8%44435%19%
2662
16th to endNight
12%16%6%8%6%35%345%27%
2633
February1st to 15thNight
13%13%5%11%8%35%445%23%
2285
16th to endNight
17%10%48%7%3435%5%28%
1955
March1st to 15thNight
18%11%5%8%6%34335%30%
2078
16th to endNight
15%6%45%5%25%34442%
2040
April1st to 15thNight
22%8%35%5%24345%35%
1796
16th to endNight
17%8%26%5%33346%37%
1724
May1st to 15thNight
21%7%25%42345%6%35%
1440
16th to endNight
15%6%25%5%335%5%7%37%
1495
June1st to 15thNight
17%6%26%6%245%5%7%34%
1440
16th to endNight
16%6%24425%5%6%8%37%
1440
July1st to 15thNight
10%314435%5%5%9%46%
1440
16th to endNight
9%5%235%35%5%6%9%45%
1514
August1st to 15thNight
9%5%35%4345%6%9%42%
1533
16th to endNight
9%324425%45%7%49%
1849
September1st to 15thNight
14%5%25%5%3445%5%43%
1800
16th to endNight
15%415%323335%49%
1962
October1st to 15thNight
18%6%35%5%2435%6%37%
2160
16th to endNight
24%9%36%5%34446%27%
2394
November1st to 15thNight
20%9%36%5%33445%33%
2539
16th to endNight
23%10%48%6%34445%24%
2730
December1st to 15thNight
21%15%48%6%35%5%45%19%
2730
16th to endNight
23%15%5%8%6%3433420%
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
20%13%5%9%8%35%345%21%
1520
16th to endDay
14%15%48%8%35%445%24%
1590
February1st to 15thDay
14%13%411%8%35%45%424%
1575
16th to endDay
18%13%47%6%25%43427%
1517
March1st to 15thDay
26%8%346%2443331%
1866
16th to endDay
24%6%2432333439%
2183
April1st to 15thDay
26%8%35%423335%33%
2152
16th to endDay
24%6%24423435%36%
2244
May1st to 15thDay
28%6%35%5%2424431%
2511
16th to endDay
27%4245%34345%34%
2618
June1st to 15thDay
25%5%345%35%446%31%
2520
16th to endDay
21%5%25%5%35%5%6%6%33%
2520
July1st to 15thDay
12%5%145%35%6%6%8%39%
2520
16th to endDay
11%5%25%435%5%7%9%38%
2654
August1st to 15thDay
22%314435%5%5%6%37%
2425
16th to endDay
21%41432445%7%40%
2339
September1st to 15thDay
15%5%245%24447%41%
2160
16th to endDay
14%5%2343445%7%45%
1997
October1st to 15thDay
19%7%36%43445%6%34%
1800
16th to endDay
24%8%36%6%34445%27%
1830
November1st to 15thDay
19%7%35%435%45%6%33%
1648
16th to endDay
24%10%47%5%35%435%25%
1560
December1st to 15thDay
20%14%48%7%45%5%45%18%
1560
16th to endDay
23%14%5%7%6%24335%22%
1664
January1st to 15thNight
17%14%6%11%7%4444419%
2662
16th to endNight
13%16%6%8%6%24345%27%
2633
February1st to 15thNight
14%12%5%11%7%35%445%25%
2278
16th to endNight
18%10%48%7%3435%5%29%
1955
March1st to 15thNight
28%8%36%42322432%
2091
16th to endNight
25%5%3431433342%
2040
April1st to 15thNight
25%7%35%423245%35%
1796
16th to endNight
20%7%25%5%33346%37%
1724
May1st to 15thNight
26%6%24423345%34%
1440
16th to endNight
21%5%345%23447%37%
1495
June1st to 15thNight
19%5%25%5%3445%6%35%
1440
16th to endNight
18%5%24425%5%5%7%37%
1440
July1st to 15thNight
10%323435%5%5%9%46%
1440
16th to endNight
8%5%235%35%46%9%45%
1514
August1st to 15thNight
14%425%323447%45%
1533
16th to endNight
16%314314345%50%
1849
September1st to 15thNight
14%425%5%345%45%43%
1800
16th to endNight
15%414323335%49%
1962
October1st to 15thNight
19%6%35%42435%6%37%
2160
16th to endNight
24%8%36%5%44446%27%
2394
November1st to 15thNight
25%8%35%42333434%
2539
16th to endNight
26%9%38%423345%27%
2730
December1st to 15thNight
22%15%37%5%3445%5%20%
2730
16th to endNight
24%14%48%6%3433422%
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
65%38%14%6%
1521
16th to endDay
61%211%14%8%
1590
February1st to 15thDay
62%311%17%4
1577
16th to endDay
58%310%16%9%1
1517
March1st to 15thDay
58%311%17%7%1
1866
16th to endDay
45%29%20%16%6%
2184
April1st to 15thDay
53%17%20%14%2
2152
16th to endDay
49%26%20%17%3
2244
May1st to 15thDay
51%27%21%14%2
2511
16th to endDay
47%411%21%12%2
2622
June1st to 15thDay
51%410%22%9%
2520
16th to endDay
47%313%22%11%1
2520
July1st to 15thDay
38%414%29%12%
2371
16th to endDay
40%5%16%27%10%
2487
August1st to 15thDay
41%418%23%11%
2411
16th to endDay
38%415%30%11%
2339
September1st to 15thDay
41%312%29%11%
2160
16th to endDay
37%413%34%9%
1997
October1st to 15thDay
50%312%23%9%
1800
16th to endDay
59%313%16%6%
1830
November1st to 15thDay
50%414%21%8%
1648
16th to endDay
62%312%13%6%1
1560
December1st to 15thDay
68%410%13%3
1560
16th to endDay
65%310%13%6%
1664
January1st to 15thNight
67%49%13%5%
2662
16th to endNight
59%39%18%8%
2633
February1st to 15thNight
61%311%17%5%
2287
16th to endNight
57%210%19%9%
1955
March1st to 15thNight
57%29%20%8%
2091
16th to endNight
46%29%20%16%4
2040
April1st to 15thNight
52%27%20%16%1
1796
16th to endNight
48%26%20%17%3
1724
May1st to 15thNight
49%27%20%15%4
1440
16th to endNight
45%411%22%14%2
1497
June1st to 15thNight
47%412%23%10%1
1440
16th to endNight
43%5%12%22%15%
1440
July1st to 15thNight
32%5%12%32%15%1
1360
16th to endNight
34%415%29%15%
1418
August1st to 15thNight
37%418%25%12%1
1523
16th to endNight
33%315%34%12%
1849
September1st to 15thNight
41%411%30%11%1
1800
16th to endNight
37%310%36%11%
1962
October1st to 15thNight
47%310%25%12%
2160
16th to endNight
57%413%18%6%
2394
November1st to 15thNight
52%313%19%10%
2539
16th to endNight
61%311%16%5%
2730
December1st to 15thNight
65%312%14%4
2730
16th to endNight
67%28%13%6%
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
28%20%31%14%31
82
16th to endDay
27%17%31%19%4
73
February1st to 15thDay
28%24%28%17%
90
16th to endDay
33%18%25%15%6%
176
March1st to 15thDay
25%13%30%26%4
270
16th to endDay
23%15%29%19%9%2
288
April1st to 15thDay
27%18%27%18%6%1
270
16th to endDay
25%13%27%17%12%3
270
May1st to 15thDay
28%9%30%18%8%4
288
16th to endDay
20%11%32%22%11%1
331
June1st to 15thDay
24%7%31%23%10%2
315
16th to endDay
16%8%32%26%13%2
315
July1st to 15thDay
14%428%30%14%6%
305
16th to endDay
13%328%26%21%6%
326
August1st to 15thDay
12%322%35%17%8%
313
16th to endDay
13%325%26%18%12%
332
September1st to 15thDay
19%6%19%18%23%12%
315
16th to endDay
14%6%23%22%21%10%
314
October1st to 15thDay
21%9%26%24%14%3
315
16th to endDay
29%16%23%22%7%
313
November1st to 15thDay
24%10%27%25%10%1
212
16th to endDay
31%16%37%10%4
90
December1st to 15thDay
24%16%37%17%3
90
16th to endDay
34%22%30%11%1
96
January1st to 15thNight
25%13%33%21%5%
765
16th to endNight
22%12%30%27%6%
768
February1st to 15thNight
20%13%36%23%5%
704
16th to endNight
24%14%29%25%5%
631
March1st to 15thNight
25%12%31%27%3
720
16th to endNight
20%14%25%28%10%
768
April1st to 15thNight
27%12%28%24%5%
718
16th to endNight
23%11%28%27%8%
644
May1st to 15thNight
25%6%25%30%10%1
360
16th to endNight
18%5%33%28%13%
375
June1st to 15thNight
19%5%27%34%13%
360
16th to endNight
18%323%39%13%1
360
July1st to 15thNight
10%125%43%17%1
340
16th to endNight
10%321%45%17%2
376
August1st to 15thNight
13%218%40%23%1
452
16th to endNight
10%420%38%23%2
703
September1st to 15thNight
17%423%30%20%2
720
16th to endNight
17%5%22%27%24%3
717
October1st to 15thNight
23%8%23%29%13%1
720
16th to endNight
29%11%25%25%7%
768
November1st to 15thNight
26%8%26%25%11%
760
16th to endNight
31%13%25%20%8%
780
December1st to 15thNight
30%13%29%21%4
780
16th to endNight
32%12%29%20%41
832
Page generated at 2018-01-12 22:01:29. Version ac04

Copyright 2018 A. Danko


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