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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 2021-02-22.

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
30%
18997
15%
60830
9%
18966
38%
18966
17%
42390

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%
960
9%
3346
4%
956
23%
956
8%
2645
January16th to endNight
20%
1024
12%
3510
7%
1024
27%
1024
11%
2596
February1st to 15thNight
17%
943
12%
3067
4%
941
27%
941
12%
2283
February16th to endNight
23%
817
14%
2534
6%
817
33%
817
14%
1851
March1st to 15thNight
20%
900
13%
2614
7%
900
27%
900
14%
1979
March16th to endNight
30%
960
21%
2550
10%
960
39%
960
23%
1718
April1st to 15thNight
22%
898
16%
2246
5%
898
27%
898
19%
1646
April16th to endNight
31%
795
19%
2131
8%
795
38%
795
22%
1480
May1st to 15thNight
35%
450
18%
1800
18%
450
44%
450
17%
1148
May16th to endNight
35%
471
16%
1881
12%
470
50%
470
22%
1136
June1st to 15thNight
39%
450
12%
1800
13%
450
48%
450
18%
1149
June16th to endNight
46%
450
12%
1800
15%
450
54%
450
21%
1062
July1st to 15thNight
56%
430
17%
1720
24%
430
63%
430
29%
905
July16th to endNight
54%
472
16%
1802
20%
450
58%
450
26%
1009
August1st to 15thNight
55%
556
17%
1877
15%
554
60%
554
28%
1119
August16th to endNight
50%
880
20%
2314
11%
880
55%
880
36%
1443
September1st to 15thNight
45%
900
18%
2250
10%
900
47%
900
31%
1506
September16th to endNight
48%
897
24%
2452
16%
897
54%
897
33%
1537
October1st to 15thNight
34%
900
18%
2700
11%
900
43%
900
20%
1841
October16th to endNight
24%
960
13%
2992
6%
960
33%
960
14%
2211
November1st to 15thNight
27%
940
17%
3140
12%
940
36%
940
16%
2181
November16th to endNight
21%
960
11%
3360
6%
960
28%
960
10%
2528
December1st to 15thNight
18%
960
10%
3360
5%
960
25%
960
9%
2630
December16th to endNight
15%
1024
11%
3584
4%
1024
24%
1024
9%
2787

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
16%8%36%5%35%45%6%33%
61397
Night
16%9%37%6%34446%32%
60999
Cloud CoverDay
19%7%36%5%3445%6%33%
61406
Night
19%9%36%5%34446%33%
61005
TransparencyDay
50%311%21%11%1
61084
Night
52%310%21%10%1
60830
SeeingDay
22%12%29%21%10%3
9663
Night
22%10%27%27%10%
18998

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%14%411%8%35%34420%
1912
16th to endDay
13%15%5%9%7%45%446%23%
2120
February1st to 15thDay
13%14%5%10%7%4445%5%24%
2115
16th to endDay
17%13%48%6%25%45%5%27%
1956
March1st to 15thDay
17%12%46%8%35%44427%
2323
16th to endDay
16%8%35%435%445%39%
2730
April1st to 15thDay
23%8%37%433345%31%
2692
16th to endDay
21%8%25%5%33435%36%
2773
May1st to 15thDay
18%7%36%6%35%345%33%
3141
16th to endDay
15%6%25%6%45%5%5%6%36%
3290
June1st to 15thDay
19%6%35%5%35%447%33%
3150
16th to endDay
15%6%345%35%6%6%7%34%
3150
July1st to 15thDay
10%424425%5%6%9%42%
3150
16th to endDay
10%5%25%5%35%5%7%9%39%
3326
August1st to 15thDay
10%5%26%5%36%6%5%8%39%
2983
16th to endDay
10%5%25%435%5%6%8%41%
2927
September1st to 15thDay
14%5%25%5%35%5%48%39%
2700
16th to endDay
12%5%144245%5%7%44%
2496
October1st to 15thDay
19%7%36%43446%6%33%
2250
16th to endDay
25%7%36%6%35%446%26%
2288
November1st to 15thDay
17%9%35%5%35%5%5%6%30%
2037
16th to endDay
21%10%48%7%35%5%45%23%
1920
December1st to 15thDay
18%15%49%8%45%5%45%16%
1920
16th to endDay
21%13%6%8%7%25%33422%
2048
January1st to 15thNight
17%14%5%11%7%44435%19%
3346
16th to endNight
13%15%6%8%6%34345%26%
3510
February1st to 15thNight
13%13%5%10%8%35%445%24%
3065
16th to endNight
15%10%49%7%3435%5%28%
2534
March1st to 15thNight
17%13%5%8%6%34335%27%
2601
16th to endNight
16%6%35%5%2434441%
2550
April1st to 15thNight
21%8%36%5%24345%33%
2246
16th to endNight
19%8%25%5%33346%36%
2131
May1st to 15thNight
20%7%25%43445%6%36%
1800
16th to endNight
15%6%25%5%3345%7%40%
1879
June1st to 15thNight
17%5%26%6%345%6%7%35%
1800
16th to endNight
14%6%245%25%5%6%7%40%
1800
July1st to 15thNight
9%314435%5%5%9%47%
1800
16th to endNight
9%5%245%35%5%6%9%43%
1898
August1st to 15thNight
7%5%36%5%345%6%8%42%
1887
16th to endNight
9%425%5%2445%7%48%
2314
September1st to 15thNight
14%425%5%25%45%6%42%
2250
16th to endNight
15%414423346%48%
2452
October1st to 15thNight
18%7%35%5%25%45%6%35%
2700
16th to endNight
23%9%36%5%44446%26%
2992
November1st to 15thNight
20%9%36%5%33345%32%
3140
16th to endNight
22%11%48%6%35%446%23%
3360
December1st to 15thNight
20%15%48%6%35%5%45%19%
3360
16th to endNight
21%14%5%8%6%34445%21%
3584

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%14%5%10%8%35%34420%
1912
16th to endDay
13%15%5%9%7%45%445%24%
2120
February1st to 15thDay
14%13%410%7%35%45%425%
2115
16th to endDay
17%13%47%6%25%5%45%27%
1956
March1st to 15thDay
24%10%35%6%2433330%
2333
16th to endDay
23%7%2442433438%
2729
April1st to 15thDay
26%8%36%5%23345%30%
2692
16th to endDay
25%7%25%423435%35%
2773
May1st to 15thDay
26%6%35%5%3434432%
3141
16th to endDay
23%4245%34446%35%
3290
June1st to 15thDay
23%5%345%35%446%33%
3150
16th to endDay
18%5%25%5%25%5%6%6%34%
3150
July1st to 15thDay
10%4145%35%5%6%8%43%
3150
16th to endDay
11%5%25%5%35%5%7%9%39%
3326
August1st to 15thDay
20%3144345%46%39%
2983
16th to endDay
19%41442445%7%41%
2927
September1st to 15thDay
14%5%245%25%5%47%40%
2700
16th to endDay
13%42443445%7%44%
2496
October1st to 15thDay
19%7%36%43445%6%33%
2250
16th to endDay
25%8%36%6%34445%27%
2288
November1st to 15thDay
20%8%35%5%35%5%5%6%31%
2037
16th to endDay
22%11%37%6%35%5%45%24%
1920
December1st to 15thDay
19%15%49%7%45%5%45%17%
1920
16th to endDay
21%14%5%8%6%25%335%22%
2048
January1st to 15thNight
17%14%6%10%7%4444420%
3346
16th to endNight
13%16%6%8%7%34345%26%
3510
February1st to 15thNight
14%13%410%7%34445%26%
3058
16th to endNight
16%10%49%7%3435%5%29%
2534
March1st to 15thNight
26%11%37%5%2332429%
2614
16th to endNight
23%6%2432434441%
2550
April1st to 15thNight
23%8%36%5%23335%33%
2246
16th to endNight
20%7%25%423346%36%
2131
May1st to 15thNight
24%6%2443335%5%35%
1800
16th to endNight
19%5%24423447%40%
1879
June1st to 15thNight
18%5%26%5%3446%6%35%
1800
16th to endNight
16%5%244245%5%7%40%
1800
July1st to 15thNight
10%324435%5%5%9%47%
1800
16th to endNight
8%5%245%35%45%9%43%
1898
August1st to 15thNight
11%5%25%33345%7%45%
1887
16th to endNight
14%415%414346%48%
2314
September1st to 15thNight
14%5%25%5%3445%6%43%
2250
16th to endNight
14%5%14423346%48%
2452
October1st to 15thNight
18%7%35%5%25%45%6%36%
2700
16th to endNight
23%8%36%5%44446%27%
2992
November1st to 15thNight
23%9%35%43334433%
3140
16th to endNight
25%10%37%424445%26%
3360
December1st to 15thNight
21%14%38%6%34445%20%
3360
16th to endNight
22%14%48%6%34335%22%
3584

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%28%14%6%
1913
16th to endDay
62%310%15%8%
2120
February1st to 15thDay
61%211%19%41
2117
16th to endDay
58%39%16%10%1
1956
March1st to 15thDay
59%311%17%8%1
2333
16th to endDay
46%28%19%16%5%
2730
April1st to 15thDay
55%26%18%14%2
2692
16th to endDay
51%26%19%16%3
2773
May1st to 15thDay
52%26%21%14%2
3141
16th to endDay
46%411%22%13%2
3294
June1st to 15thDay
50%49%22%11%1
3150
16th to endDay
45%412%23%12%1
3150
July1st to 15thDay
34%414%30%14%1
3001
16th to endDay
39%414%28%11%
3159
August1st to 15thDay
40%417%24%11%
2969
16th to endDay
38%414%30%11%
2927
September1st to 15thDay
42%312%28%11%
2700
16th to endDay
37%414%32%10%
2496
October1st to 15thDay
49%312%22%10%
2250
16th to endDay
59%312%16%6%
2288
November1st to 15thDay
52%413%20%8%
2037
16th to endDay
62%311%14%6%1
1920
December1st to 15thDay
68%410%13%3
1920
16th to endDay
66%310%13%6%
2048
January1st to 15thNight
66%49%13%5%
3346
16th to endNight
60%38%18%9%
3510
February1st to 15thNight
60%210%18%6%
3067
16th to endNight
57%29%19%9%
2534
March1st to 15thNight
59%38%19%8%
2614
16th to endNight
45%28%21%17%4
2550
April1st to 15thNight
52%36%20%15%
2246
16th to endNight
48%36%18%19%3
2131
May1st to 15thNight
48%36%21%16%3
1800
16th to endNight
42%312%23%16%2
1881
June1st to 15thNight
46%411%23%12%1
1800
16th to endNight
40%5%12%24%16%
1800
July1st to 15thNight
31%5%11%31%17%1
1720
16th to endNight
36%413%29%14%
1802
August1st to 15thNight
37%416%27%12%1
1877
16th to endNight
35%315%33%12%
2314
September1st to 15thNight
40%411%29%12%
2250
16th to endNight
37%312%36%10%
2452
October1st to 15thNight
48%49%24%12%
2700
16th to endNight
57%312%18%6%
2992
November1st to 15thNight
53%312%19%10%
3140
16th to endNight
61%411%16%5%
3360
December1st to 15thNight
65%311%15%4
3360
16th to endNight
65%39%14%7%
3584

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
22%20%32%20%4
180
16th to endDay
21%19%36%18%3
219
February1st to 15thDay
30%20%36%12%
270
16th to endDay
31%19%31%13%3
339
March1st to 15thDay
28%14%32%20%3
450
16th to endDay
27%15%30%18%7%1
480
April1st to 15thDay
33%18%26%14%6%1
450
16th to endDay
29%14%25%17%9%2
439
May1st to 15thDay
26%13%30%20%6%3
468
16th to endDay
19%14%32%21%10%
523
June1st to 15thDay
25%9%29%23%8%2
495
16th to endDay
15%10%31%25%13%2
495
July1st to 15thDay
10%327%35%17%5%
485
16th to endDay
13%5%31%27%18%4
518
August1st to 15thDay
13%5%24%32%16%7%
478
16th to endDay
13%6%26%26%17%9%
524
September1st to 15thDay
19%8%26%18%17%9%
495
16th to endDay
14%8%29%23%16%7%
494
October1st to 15thDay
23%13%28%21%11%2
495
16th to endDay
31%16%25%20%6%
483
November1st to 15thDay
31%12%29%19%6%1
331
16th to endDay
30%21%32%11%5%
180
December1st to 15thDay
27%15%38%15%2
180
16th to endDay
29%22%32%10%4
192
January1st to 15thNight
26%13%32%21%5%
960
16th to endNight
23%13%31%25%5%
1024
February1st to 15thNight
21%13%36%22%4
944
16th to endNight
23%15%30%25%4
817
March1st to 15thNight
25%12%32%25%3
900
16th to endNight
21%14%27%27%9%
960
April1st to 15thNight
27%13%28%24%5%
898
16th to endNight
24%11%27%26%8%
795
May1st to 15thNight
23%7%25%31%10%1
450
16th to endNight
17%5%35%28%12%
471
June1st to 15thNight
18%5%28%34%12%
450
16th to endNight
16%323%38%15%1
450
July1st to 15thNight
10%123%45%18%1
430
16th to endNight
10%222%45%16%1
472
August1st to 15thNight
11%319%40%23%1
556
16th to endNight
11%421%38%21%2
880
September1st to 15thNight
17%5%25%29%19%2
900
16th to endNight
17%5%23%28%21%2
897
October1st to 15thNight
23%9%26%28%11%1
900
16th to endNight
29%12%26%25%6%
960
November1st to 15thNight
27%10%27%24%9%
940
16th to endNight
30%14%25%20%8%
960
December1st to 15thNight
29%13%29%22%4
960
16th to endNight
30%12%29%20%4
1024
Page generated at 2021-02-23 07:37:59. Version ac04

Copyright 2021 A. Danko


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