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Deer Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Deer Lake clear sky chart from 2005-11-05 to 2017-08-12.

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
28%
14835
18%
46461
8%
14804
39%
14804
19%
30337

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
15%
720
20%
2506
7%
716
33%
716
14%
1582
January16th to endNight
16%
768
20%
2664
5%
768
35%
768
14%
1657
February1st to 15thNight
13%
704
18%
2174
4%
701
29%
701
16%
1448
February16th to endNight
16%
631
24%
1893
7%
631
38%
631
18%
1217
March1st to 15thNight
19%
720
17%
2160
6%
720
33%
720
16%
1443
March16th to endNight
20%
768
23%
2010
6%
768
33%
768
22%
1330
April1st to 15thNight
22%
718
17%
1796
5%
718
29%
718
20%
1264
April16th to endNight
24%
645
17%
1725
3%
645
33%
645
20%
1193
May1st to 15thNight
25%
540
16%
1620
5%
540
35%
540
15%
1141
May16th to endNight
29%
390
12%
1513
8%
390
38%
390
13%
1001
June1st to 15thNight
34%
360
13%
1440
12%
360
45%
360
16%
949
June16th to endNight
48%
360
13%
1440
13%
360
57%
360
21%
839
July1st to 15thNight
43%
340
11%
1360
15%
340
47%
340
18%
848
July16th to endNight
49%
376
15%
1418
15%
354
58%
354
20%
870
August1st to 15thNight
50%
506
17%
1555
11%
504
55%
504
26%
966
August16th to endNight
55%
700
16%
1750
8%
700
58%
700
30%
1183
September1st to 15thNight
44%
660
21%
1678
11%
660
48%
660
29%
1102
September16th to endNight
45%
657
23%
1815
14%
657
52%
657
28%
1162
October1st to 15thNight
30%
660
22%
1873
11%
660
41%
660
22%
1250
October16th to endNight
23%
704
16%
2249
5%
704
37%
704
19%
1480
November1st to 15thNight
26%
700
20%
2277
10%
700
40%
700
19%
1456
November16th to endNight
21%
720
20%
2340
8%
720
36%
720
17%
1508
December1st to 15thNight
22%
720
16%
2517
5%
720
35%
720
12%
1658
December16th to endNight
14%
768
18%
2688
4%
768
30%
768
12%
1790

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%5%2442445%7%41%
47517
Night
18%6%24424446%41%
46631
Cloud CoverDay
17%5%2442445%7%41%
47527
Night
17%6%24424446%41%
46636
TransparencyDay
40%6%13%22%15%2
47205
Night
43%5%12%21%15%2
46461
SeeingDay
18%18%27%22%10%2
5720
Night
18%23%25%22%8%1
14836

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
17%6%2442445%5%42%
1432
16th to endDay
16%6%3442245%7%41%
1557
February1st to 15thDay
16%6%246%35%446%38%
1685
16th to endDay
17%5%246%245%5%5%39%
1580
March1st to 15thDay
20%5%35%5%24347%38%
1790
16th to endDay
18%6%25%424335%41%
2213
April1st to 15thDay
21%5%2432335%5%41%
2152
16th to endDay
18%5%23423346%45%
2235
May1st to 15thDay
25%6%2442335%5%36%
2332
16th to endDay
18%434424448%40%
2610
June1st to 15thDay
23%5%2442445%8%34%
2520
16th to endDay
13%5%245%245%6%8%40%
2520
July1st to 15thDay
13%6%23425%5%6%10%38%
2520
16th to endDay
13%4244245%6%9%39%
2654
August1st to 15thDay
14%3145%25%5%6%8%41%
2297
16th to endDay
12%5%25%42446%7%43%
2100
September1st to 15thDay
14%425%433447%45%
1950
16th to endDay
17%314424346%47%
1815
October1st to 15thDay
18%6%2442435%5%43%
1755
16th to endDay
15%42442445%7%43%
1623
November1st to 15thDay
19%6%23423335%43%
1581
16th to endDay
18%423424447%44%
1620
December1st to 15thDay
19%5%25%424346%41%
1440
16th to endDay
22%8%25%423246%37%
1536
January1st to 15thNight
19%6%24423346%42%
2506
16th to endNight
17%8%34413345%43%
2664
February1st to 15thNight
15%8%35%5%24346%40%
2173
16th to endNight
18%5%2443445%5%43%
1893
March1st to 15thNight
20%6%24424446%40%
2147
16th to endNight
17%6%34424335%45%
2010
April1st to 15thNight
19%7%25%433445%39%
1796
16th to endNight
21%5%25%42334440%
1725
May1st to 15thNight
21%6%34335%446%35%
1620
16th to endNight
20%6%2442445%9%36%
1511
June1st to 15thNight
22%5%25%424346%38%
1440
16th to endNight
14%32342445%8%45%
1440
July1st to 15thNight
14%5%235%36%6%5%8%38%
1440
16th to endNight
11%6%25%5%35%5%6%9%36%
1514
August1st to 15thNight
10%5%15%4346%7%8%41%
1565
16th to endNight
11%5%25%5%35%5%47%43%
1750
September1st to 15thNight
15%5%2442446%6%44%
1678
16th to endNight
15%415%5%2432449%
1815
October1st to 15thNight
17%6%245%23345%44%
1873
16th to endNight
18%5%25%434445%41%
2249
November1st to 15thNight
17%6%24323345%44%
2277
16th to endNight
19%5%25%324436%41%
2340
December1st to 15thNight
21%6%24424346%38%
2517
16th to endNight
21%6%245%3435%6%37%
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
17%6%24423446%43%
1432
16th to endDay
16%7%25%5%1335%6%42%
1557
February1st to 15thDay
16%5%25%435%447%39%
1685
16th to endDay
17%5%345%25%5%5%6%39%
1580
March1st to 15thDay
20%5%35%5%24337%38%
1800
16th to endDay
18%6%34423345%42%
2213
April1st to 15thDay
21%424323446%42%
2152
16th to endDay
17%5%2342335%6%44%
2235
May1st to 15thDay
25%6%23424346%36%
2332
16th to endDay
17%5%24424447%41%
2610
June1st to 15thDay
21%6%2442345%8%35%
2520
16th to endDay
12%5%24435%46%8%42%
2520
July1st to 15thDay
13%4244345%6%9%40%
2520
16th to endDay
13%4244245%6%9%40%
2654
August1st to 15thDay
13%414435%5%6%9%42%
2297
16th to endDay
11%5%25%3245%5%8%44%
2100
September1st to 15thDay
13%415%5%34347%46%
1950
16th to endDay
17%423424346%47%
1815
October1st to 15thDay
17%6%24323445%43%
1755
16th to endDay
14%5%2442445%6%44%
1623
November1st to 15thDay
19%6%24423335%44%
1581
16th to endDay
17%4145%14447%44%
1620
December1st to 15thDay
19%5%25%42435%6%40%
1440
16th to endDay
23%8%24423346%37%
1536
January1st to 15thNight
19%7%14323345%42%
2506
16th to endNight
17%8%24423345%44%
2664
February1st to 15thNight
15%8%35%5%34345%41%
2166
16th to endNight
18%5%23434346%43%
1893
March1st to 15thNight
20%6%3442335%6%40%
2160
16th to endNight
17%6%24424345%45%
2009
April1st to 15thNight
19%7%24433346%39%
1796
16th to endNight
21%6%25%41343440%
1725
May1st to 15thNight
21%6%25%435%346%34%
1620
16th to endNight
20%6%2442445%9%35%
1511
June1st to 15thNight
22%6%24424346%37%
1440
16th to endNight
14%32342446%8%44%
1440
July1st to 15thNight
13%5%25%5%35%5%6%8%37%
1440
16th to endNight
11%6%35%435%6%5%10%36%
1514
August1st to 15thNight
10%4145%346%7%9%41%
1565
16th to endNight
11%5%25%435%5%5%7%43%
1750
September1st to 15thNight
14%5%2442445%7%43%
1678
16th to endNight
15%425%32434449%
1815
October1st to 15thNight
16%6%34433335%43%
1873
16th to endNight
18%5%16%4235%46%41%
2249
November1st to 15thNight
17%6%25%423345%45%
2277
16th to endNight
20%424424336%41%
2340
December1st to 15thNight
21%6%23334346%38%
2517
16th to endNight
22%5%245%24446%37%
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
42%5%15%22%12%3
1433
16th to endDay
42%412%25%13%2
1557
February1st to 15thDay
43%5%14%21%13%1
1688
16th to endDay
42%5%11%24%14%2
1580
March1st to 15thDay
44%5%15%22%10%2
1800
16th to endDay
42%411%18%18%3
2213
April1st to 15thDay
42%5%11%20%16%3
2152
16th to endDay
39%5%10%22%18%3
2235
May1st to 15thDay
47%6%9%20%14%2
2332
16th to endDay
40%8%15%20%13%2
2614
June1st to 15thDay
45%6%13%21%10%1
2520
16th to endDay
35%8%15%25%13%1
2520
July1st to 15thDay
36%8%13%23%16%1
2371
16th to endDay
36%7%16%23%13%3
2487
August1st to 15thDay
34%8%17%23%15%
2283
16th to endDay
35%7%11%25%18%1
2100
September1st to 15thDay
35%7%14%20%20%1
1950
16th to endDay
36%5%8%22%24%2
1815
October1st to 15thDay
41%411%22%16%2
1755
16th to endDay
38%6%12%24%15%1
1623
November1st to 15thDay
43%313%18%18%2
1581
16th to endDay
40%413%25%13%2
1620
December1st to 15thDay
44%417%18%13%
1440
16th to endDay
48%415%18%12%
1536
January1st to 15thNight
43%412%22%13%2
2506
16th to endNight
42%411%23%15%2
2664
February1st to 15thNight
45%5%12%21%12%2
2174
16th to endNight
42%410%22%16%3
1893
March1st to 15thNight
44%5%14%19%13%3
2160
16th to endNight
40%410%20%19%4
2010
April1st to 15thNight
45%410%21%14%2
1796
16th to endNight
45%48%19%17%4
1725
May1st to 15thNight
49%6%10%16%14%2
1620
16th to endNight
46%8%15%16%11%1
1513
June1st to 15thNight
46%6%11%18%14%2
1440
16th to endNight
36%7%15%24%15%
1440
July1st to 15thNight
40%8%12%21%14%1
1360
16th to endNight
39%8%14%23%11%2
1418
August1st to 15thNight
33%10%14%23%15%2
1555
16th to endNight
38%7%12%24%16%
1750
September1st to 15thNight
38%5%12%24%17%
1678
16th to endNight
38%47%20%26%1
1815
October1st to 15thNight
43%5%9%21%16%3
1873
16th to endNight
44%5%14%19%14%
2249
November1st to 15thNight
42%411%19%18%3
2277
16th to endNight
44%412%23%11%2
2340
December1st to 15thNight
47%5%14%19%12%
2517
16th to endNight
47%5%12%20%12%1
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
15%33%33%15%3
60
16th to endDay
26%17%41%13%
67
February1st to 15thDay
17%25%40%13%2
201
16th to endDay
15%28%33%17%5%
239
March1st to 15thDay
22%31%26%15%4
270
16th to endDay
21%25%34%14%31
288
April1st to 15thDay
20%25%28%18%6%
270
16th to endDay
19%20%29%18%8%2
270
May1st to 15thDay
32%22%20%15%6%2
288
16th to endDay
23%15%24%22%12%1
331
June1st to 15thDay
20%17%26%19%13%2
315
16th to endDay
15%15%28%25%12%2
315
July1st to 15thDay
15%9%26%28%16%3
305
16th to endDay
12%13%23%34%12%3
326
August1st to 15thDay
13%8%21%35%15%6%
297
16th to endDay
11%8%18%30%19%10%
268
September1st to 15thDay
14%12%23%26%16%7%
255
16th to endDay
18%9%25%24%13%7%
254
October1st to 15thDay
20%14%21%27%12%3
255
16th to endDay
13%21%35%21%7%1
247
November1st to 15thDay
20%22%26%18%10%2
235
16th to endDay
14%28%27%21%7%
240
December1st to 15thDay
20%23%36%13%5%1
60
16th to endDay
34%23%29%12%
64
January1st to 15thNight
18%34%28%15%3
720
16th to endNight
19%32%29%17%1
768
February1st to 15thNight
16%29%35%17%1
704
16th to endNight
19%29%31%16%2
631
March1st to 15thNight
22%28%26%19%3
720
16th to endNight
17%27%31%17%5%
768
April1st to 15thNight
20%26%28%20%3
718
16th to endNight
20%24%24%22%6%
645
May1st to 15thNight
20%24%24%20%9%
540
16th to endNight
21%20%20%26%8%
391
June1st to 15thNight
21%20%18%26%11%
360
16th to endNight
14%16%15%38%13%
360
July1st to 15thNight
14%14%18%33%17%1
340
16th to endNight
13%18%13%38%15%1
376
August1st to 15thNight
12%10%19%38%17%
506
16th to endNight
11%10%13%37%22%4
700
September1st to 15thNight
14%13%22%28%17%3
660
16th to endNight
18%11%17%27%19%5%
657
October1st to 15thNight
19%16%28%23%10%1
660
16th to endNight
19%19%34%18%6%
704
November1st to 15thNight
18%26%25%18%9%2
700
16th to endNight
16%31%25%19%5%
720
December1st to 15thNight
24%28%21%19%5%
720
16th to endNight
22%32%27%15%1
768
Page generated at 2017-08-13 14:16:52. Version ac04

Copyright 2017 A. Danko


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