Sandy Cove
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sandy Cove clear sky chart from 2005-11-05 to 2017-12-04.

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
28%
15185
12%
47653
8%
15152
34%
15152
16%
34810

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
11%
837
5%
2624
2%
834
15%
834
6%
2238
January16th to endNight
19%
768
11%
2526
5%
768
26%
768
10%
2018
February1st to 15thNight
15%
703
8%
2287
3%
701
21%
701
9%
1828
February16th to endNight
20%
631
10%
2047
5%
631
27%
631
10%
1586
March1st to 15thNight
18%
720
12%
1980
4%
720
24%
720
14%
1509
March16th to endNight
30%
768
19%
2112
10%
768
37%
768
23%
1443
April1st to 15thNight
22%
718
15%
1806
6%
718
28%
718
19%
1370
April16th to endNight
31%
542
17%
1622
9%
542
37%
542
21%
1129
May1st to 15thNight
36%
438
16%
1518
14%
438
42%
438
20%
1000
May16th to endNight
37%
374
13%
1497
11%
374
48%
374
21%
883
June1st to 15thNight
39%
360
10%
1352
9%
360
46%
360
18%
877
June16th to endNight
43%
360
11%
1260
10%
360
48%
360
22%
798
July1st to 15thNight
50%
340
16%
1196
18%
340
55%
340
31%
665
July16th to endNight
51%
418
13%
1457
13%
393
55%
393
24%
865
August1st to 15thNight
54%
539
14%
1609
11%
536
57%
536
28%
1024
August16th to endNight
50%
610
18%
1756
9%
610
55%
610
31%
1092
September1st to 15thNight
44%
720
16%
1800
7%
720
47%
720
31%
1185
September16th to endNight
45%
717
21%
2006
13%
717
50%
717
30%
1279
October1st to 15thNight
31%
720
16%
2160
11%
720
38%
720
19%
1521
October16th to endNight
18%
768
9%
2304
4%
768
24%
768
10%
1843
November1st to 15thNight
25%
760
14%
2652
11%
760
31%
760
14%
1911
November16th to endNight
19%
780
9%
2730
6%
780
24%
780
9%
2181
December1st to 15thNight
12%
736
6%
2574
2%
736
17%
736
5%
2217
December16th to endNight
11%
858
7%
2778
3%
858
15%
858
6%
2348

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
19%10%47%5%34446%29%
48838
Night
18%12%47%5%34445%29%
47817
Cloud CoverDay
19%11%47%5%34446%28%
48848
Night
18%12%47%5%34445%29%
47822
TransparencyDay
56%310%19%9%
48520
Night
56%311%18%9%
47653
SeeingDay
25%12%29%20%9%3
5966
Night
25%11%27%24%9%1
15189

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%19%8%10%5%3423417%
1310
16th to endDay
14%18%8%11%7%44345%17%
1695
February1st to 15thDay
13%17%8%13%7%3434419%
1575
16th to endDay
15%18%7%10%6%3434320%
1422
March1st to 15thDay
17%14%5%7%5%44436%25%
1969
16th to endDay
13%9%37%5%34445%36%
2112
April1st to 15thDay
22%12%5%5%323336%30%
2150
16th to endDay
21%9%35%423236%36%
2340
May1st to 15thDay
21%8%36%43445%6%31%
2433
16th to endDay
17%5%26%5%245%47%38%
2618
June1st to 15thDay
21%8%36%5%3445%7%29%
2604
16th to endDay
19%6%36%6%35%5%5%7%32%
2700
July1st to 15thDay
16%425%5%35%45%8%38%
2694
16th to endDay
14%6%35%5%35%5%7%9%32%
2609
August1st to 15thDay
15%6%36%7%45%5%5%7%33%
2340
16th to endDay
16%6%25%6%36%5%5%8%34%
2433
September1st to 15thDay
20%8%26%423446%35%
2160
16th to endDay
21%6%34434436%38%
1951
October1st to 15thDay
25%10%36%423245%31%
1800
16th to endDay
34%11%46%42333420%
1920
November1st to 15thDay
23%14%5%6%5%44345%23%
1535
16th to endDay
26%18%6%9%43333416%
1560
December1st to 15thDay
20%23%7%11%5%3434411%
1468
16th to endDay
20%24%8%10%5%2433313%
1440
January1st to 15thNight
21%18%7%11%7%35%43314%
2624
16th to endNight
14%18%7%9%7%3434420%
2526
February1st to 15thNight
12%17%7%13%7%35%445%18%
2285
16th to endNight
14%17%7%10%7%33335%22%
2047
March1st to 15thNight
17%13%5%7%6%33435%28%
1968
16th to endNight
14%10%36%5%23335%40%
2112
April1st to 15thNight
22%12%44433345%31%
1806
16th to endNight
17%11%35%5%24447%35%
1622
May1st to 15thNight
18%8%26%33345%7%35%
1518
16th to endNight
14%6%2443446%8%39%
1495
June1st to 15thNight
15%8%36%435%46%6%36%
1352
16th to endNight
14%5%36%6%25%46%9%36%
1260
July1st to 15thNight
12%5%144225%5%8%46%
1266
16th to endNight
11%4244346%6%8%42%
1556
August1st to 15thNight
13%5%244245%5%6%43%
1620
16th to endNight
12%5%145%3445%7%44%
1756
September1st to 15thNight
14%5%244345%6%6%42%
1800
16th to endNight
15%5%24433446%44%
2006
October1st to 15thNight
21%8%36%424445%33%
2160
16th to endNight
28%15%36%5%3333422%
2304
November1st to 15thNight
22%12%35%5%2335%6%28%
2652
16th to endNight
25%15%5%8%6%33335%19%
2730
December1st to 15thNight
20%23%7%9%6%3443313%
2574
16th to endNight
22%21%8%10%5%2333414%
2778

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%18%9%10%5%2424416%
1310
16th to endDay
14%17%7%12%7%34435%17%
1695
February1st to 15thDay
13%18%8%13%8%4433418%
1575
16th to endDay
15%19%7%10%6%3445%219%
1422
March1st to 15thDay
17%14%5%7%5%44436%25%
1980
16th to endDay
14%9%47%6%3445%5%35%
2111
April1st to 15thDay
22%13%45%423346%30%
2150
16th to endDay
22%9%34423235%36%
2340
May1st to 15thDay
21%8%36%5%34446%30%
2433
16th to endDay
18%6%26%425%45%6%37%
2618
June1st to 15thDay
22%7%36%5%2445%7%28%
2604
16th to endDay
19%6%26%6%35%5%5%8%31%
2700
July1st to 15thDay
16%425%5%45%5%5%7%37%
2694
16th to endDay
15%5%36%5%36%6%6%8%31%
2609
August1st to 15thDay
15%7%26%7%35%5%5%7%32%
2340
16th to endDay
16%5%26%6%45%45%7%33%
2433
September1st to 15thDay
20%7%25%42345%6%35%
2160
16th to endDay
22%6%24424435%38%
1951
October1st to 15thDay
26%10%36%423245%30%
1800
16th to endDay
34%12%46%423335%19%
1920
November1st to 15thDay
23%15%46%6%34345%23%
1535
16th to endDay
26%19%6%9%5%2333316%
1560
December1st to 15thDay
20%24%7%10%6%2334411%
1468
16th to endDay
20%24%7%11%5%2423314%
1440
January1st to 15thNight
20%19%8%10%7%3443413%
2624
16th to endNight
14%18%7%10%7%34345%20%
2526
February1st to 15thNight
12%17%7%11%8%45%435%17%
2278
16th to endNight
14%16%8%11%7%3333422%
2047
March1st to 15thNight
17%14%5%8%5%34335%27%
1980
16th to endNight
15%10%35%5%23345%39%
2112
April1st to 15thNight
22%13%3443333431%
1806
16th to endNight
18%11%24434346%35%
1622
May1st to 15thNight
18%8%25%424348%35%
1518
16th to endNight
14%7%2442446%7%40%
1495
June1st to 15thNight
15%8%35%5%35%37%6%35%
1352
16th to endNight
15%6%27%425%5%6%9%35%
1260
July1st to 15thNight
13%42432346%8%46%
1266
16th to endNight
11%424425%6%6%7%42%
1556
August1st to 15thNight
14%5%1443445%6%43%
1620
16th to endNight
12%42443445%7%44%
1756
September1st to 15thNight
14%5%24435%5%5%6%42%
1800
16th to endNight
15%5%34434445%44%
2006
October1st to 15thNight
22%8%35%424445%33%
2160
16th to endNight
30%13%46%5%2343422%
2304
November1st to 15thNight
23%12%35%433346%28%
2652
16th to endNight
25%15%6%8%6%3333419%
2730
December1st to 15thNight
20%22%8%9%6%3432413%
2574
16th to endNight
22%21%8%10%5%2342314%
2778

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
72%38%9%5%
1311
16th to endDay
69%36%11%7%1
1695
February1st to 15thDay
69%18%14%5%
1577
16th to endDay
67%28%13%8%
1422
March1st to 15thDay
59%312%15%7%
1980
16th to endDay
49%39%18%15%3
2112
April1st to 15thDay
56%39%18%11%1
2150
16th to endDay
50%27%21%14%2
2340
May1st to 15thDay
53%39%19%12%1
2433
16th to endDay
46%412%22%12%2
2622
June1st to 15thDay
53%410%21%10%
2604
16th to endDay
49%5%13%20%10%1
2700
July1st to 15thDay
42%412%28%11%1
2535
16th to endDay
46%5%12%25%9%
2445
August1st to 15thDay
49%414%20%9%
2327
16th to endDay
47%5%12%25%7%
2433
September1st to 15thDay
48%413%24%9%
2160
16th to endDay
47%312%28%7%
1951
October1st to 15thDay
56%39%20%9%
1800
16th to endDay
67%310%12%5%
1920
November1st to 15thDay
63%411%14%5%
1535
16th to endDay
72%38%11%21
1560
December1st to 15thDay
75%39%8%2
1468
16th to endDay
76%27%10%3
1440
January1st to 15thNight
74%48%8%4
2624
16th to endNight
67%26%13%8%
2526
February1st to 15thNight
68%39%13%5%
2287
16th to endNight
65%29%15%6%
2047
March1st to 15thNight
60%212%16%8%
1980
16th to endNight
47%39%21%16%2
2112
April1st to 15thNight
55%36%19%12%1
1806
16th to endNight
48%48%18%17%2
1622
May1st to 15thNight
47%49%21%14%2
1518
16th to endNight
40%414%23%14%1
1497
June1st to 15thNight
46%5%12%20%13%1
1352
16th to endNight
43%5%13%25%11%
1260
July1st to 15thNight
33%413%29%16%1
1196
16th to endNight
37%6%16%26%12%
1457
August1st to 15thNight
38%6%17%25%11%1
1609
16th to endNight
37%418%29%10%
1756
September1st to 15thNight
39%5%16%27%10%
1800
16th to endNight
40%314%32%8%
2006
October1st to 15thNight
51%410%21%11%
2160
16th to endNight
67%310%13%4
2304
November1st to 15thNight
55%414%18%6%
2652
16th to endNight
68%310%12%3
2730
December1st to 15thNight
76%47%9%2
2574
16th to endNight
75%27%9%5%
2778

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
25%23%40%8%3
60
16th to endDay
34%18%28%13%41
91
February1st to 15thDay
23%32%40%4
90
16th to endDay
45%14%29%9%
81
March1st to 15thDay
28%14%34%15%5%1
270
16th to endDay
21%17%31%19%7%2
288
April1st to 15thDay
26%16%30%18%5%2
270
16th to endDay
27%13%29%16%7%5%
270
May1st to 15thDay
34%6%23%19%10%5%
288
16th to endDay
21%16%32%14%11%3
331
June1st to 15thDay
27%14%27%22%7%
399
16th to endDay
21%12%34%22%8%1
495
July1st to 15thDay
16%10%32%24%12%2
469
16th to endDay
15%10%30%28%11%4
326
August1st to 15thDay
19%424%30%12%8%
313
16th to endDay
21%7%25%19%18%8%
332
September1st to 15thDay
21%6%25%21%14%9%
315
16th to endDay
23%6%22%26%16%4
314
October1st to 15thDay
30%11%27%20%6%3
315
16th to endDay
40%15%25%14%3
336
November1st to 15thDay
33%17%32%14%2
92
16th to endDay
37%20%31%10%1
90
December1st to 15thDay
34%22%26%13%2
67
16th to endDay
35%29%28%41
64
January1st to 15thNight
32%16%30%15%4
839
16th to endNight
24%13%33%19%7%1
768
February1st to 15thNight
23%16%34%20%5%
704
16th to endNight
26%18%28%22%4
631
March1st to 15thNight
25%19%31%19%3
720
16th to endNight
21%13%28%26%9%1
768
April1st to 15thNight
30%12%30%21%5%
718
16th to endNight
24%10%28%23%12%
542
May1st to 15thNight
23%6%27%29%11%
438
16th to endNight
15%9%33%33%9%
375
June1st to 15thNight
16%8%28%34%11%
360
16th to endNight
17%6%25%40%10%
360
July1st to 15thNight
13%227%40%15%
340
16th to endNight
13%426%35%19%
418
August1st to 15thNight
16%217%38%21%3
539
16th to endNight
15%423%32%20%3
610
September1st to 15thNight
17%6%26%27%16%4
720
16th to endNight
18%6%24%28%19%3
717
October1st to 15thNight
27%8%27%25%9%1
720
16th to endNight
36%14%25%17%5%
768
November1st to 15thNight
32%11%25%21%8%
760
16th to endNight
36%13%25%20%4
780
December1st to 15thNight
33%16%28%16%4
736
16th to endNight
36%13%29%16%3
858
Page generated at 2017-12-05 10:19:04. Version ac04

Copyright 2017 A. Danko


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