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 2017-12-02.

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
22%
15422
6%
47790
3%
15379
25%
15379
9%
39482

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
10%
747
4%
2539
2%
746
13%
746
3%
2312
January16th to endNight
18%
800
4%
2688
3%
800
19%
800
4%
2402
February1st to 15thNight
14%
726
2%
2417
1%
723
16%
723
3%
2198
February16th to endNight
18%
631
4%
1903
1%
631
22%
631
7%
1641
March1st to 15thNight
21%
717
7%
2148
4%
716
24%
716
9%
1785
March16th to endNight
21%
606
8%
2010
4%
606
27%
606
8%
1661
April1st to 15thNight
19%
539
7%
1796
5%
539
23%
539
9%
1446
April16th to endNight
22%
540
10%
1613
8%
540
26%
540
11%
1285
May1st to 15thNight
28%
540
8%
1440
4%
540
30%
540
16%
1113
May16th to endNight
28%
561
7%
1409
3%
560
30%
560
14%
1138
June1st to 15thNight
27%
540
2%
1260
1%
540
27%
540
13%
1047
June16th to endNight
30%
540
3%
1260
2%
540
32%
540
19%
980
July1st to 15thNight
31%
510
4%
1253
2%
510
33%
510
21%
909
July16th to endNight
35%
565
7%
1419
3%
532
38%
532
19%
1057
August1st to 15thNight
36%
539
7%
1429
4%
535
38%
535
18%
1096
August16th to endNight
35%
573
9%
1789
6%
573
37%
573
17%
1315
September1st to 15thNight
28%
540
8%
1812
7%
540
33%
540
15%
1324
September16th to endNight
25%
538
10%
1980
7%
538
31%
538
12%
1441
October1st to 15thNight
24%
665
10%
2127
5%
665
30%
665
12%
1622
October16th to endNight
20%
816
8%
2496
4%
816
23%
816
9%
2042
November1st to 15thNight
21%
805
8%
2511
4%
805
24%
805
8%
2113
November16th to endNight
13%
825
6%
2885
2%
825
17%
825
4%
2462
December1st to 15thNight
13%
759
2%
2726
1%
759
15%
759
3%
2474
December16th to endNight
13%
800
2%
2880
2%
800
14%
800
3%
2619

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
22%12%5%8%7%34445%20%
48657
Night
20%12%5%9%8%45%446%18%
47969
TransparencyDay
65%5%9%13%4
48341
Night
68%5%9%11%3
47803
SeeingDay
28%13%25%19%9%2
8288
Night
27%13%27%22%7%
15428

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
15%14%8%14%12%7%5%5%5%5%6%
1399
16th to endDay
13%14%8%14%14%6%8%5%426%
1536
February1st to 15thDay
15%12%6%11%14%6%6%45%5%11%
1440
16th to endDay
16%17%7%12%10%45%34313%
1569
March1st to 15thDay
16%17%6%8%6%5%5%446%17%
1790
16th to endDay
17%17%7%9%8%4433417%
2210
April1st to 15thDay
22%17%5%8%7%3434417%
2153
16th to endDay
22%16%5%7%5%23235%26%
2346
May1st to 15thDay
23%14%36%5%23335%26%
2512
16th to endDay
27%13%36%434445%22%
2702
June1st to 15thDay
31%10%36%5%34446%18%
2700
16th to endDay
26%9%36%5%2445%5%27%
2700
July1st to 15thDay
18%7%36%5%345%6%7%30%
2630
16th to endDay
24%7%46%6%45%45%6%25%
2653
August1st to 15thDay
21%8%46%6%3445%7%26%
2520
16th to endDay
23%9%36%6%3446%7%25%
2413
September1st to 15thDay
25%9%36%425%436%27%
2148
16th to endDay
22%9%47%5%435%5%7%23%
1980
October1st to 15thDay
23%11%36%5%23345%29%
1833
16th to endDay
27%16%410%6%3343414%
1728
November1st to 15thDay
23%17%5%9%7%44435%15%
1676
16th to endDay
19%17%7%11%7%46%34411%
1404
December1st to 15thDay
20%17%7%12%9%45%4448%
1271
16th to endDay
22%14%9%10%12%45%4438%
1344
January1st to 15thNight
16%14%8%13%12%5%5%5%5%48%
2539
16th to endNight
14%11%6%11%14%7%8%6%5%49%
2688
February1st to 15thNight
15%12%6%11%15%7%6%6%449%
2417
16th to endNight
13%17%7%13%9%45%445%14%
1903
March1st to 15thNight
17%13%6%8%7%46%446%19%
2147
16th to endNight
15%16%6%10%8%35%5%45%17%
2010
April1st to 15thNight
21%14%5%8%6%44447%17%
1796
16th to endNight
22%13%5%7%6%34435%23%
1613
May1st to 15thNight
21%14%45%423335%30%
1440
16th to endNight
29%10%25%42446%5%23%
1407
June1st to 15thNight
27%8%47%5%3445%7%21%
1260
16th to endNight
24%8%25%434448%27%
1260
July1st to 15thNight
19%6%37%5%3345%8%32%
1328
16th to endNight
22%6%35%5%3436%7%29%
1515
August1st to 15thNight
19%7%36%6%36%46%7%27%
1440
16th to endNight
20%7%35%6%36%5%5%7%29%
1789
September1st to 15thNight
24%8%35%425%45%5%29%
1812
16th to endNight
20%9%35%5%35%5%5%8%26%
1980
October1st to 15thNight
18%9%37%6%36%5%5%8%24%
2127
16th to endNight
26%11%38%6%35%446%19%
2496
November1st to 15thNight
23%14%5%8%6%445%46%16%
2511
16th to endNight
22%14%6%11%8%44445%12%
2885
December1st to 15thNight
19%17%7%11%8%5%6%4449%
2726
16th to endNight
20%16%8%12%9%45%5%338%
2880

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
81%6%6%5%1
1400
16th to endDay
82%5%35%2
1536
February1st to 15thDay
74%7%8%7%2
1443
16th to endDay
77%5%38%4
1569
March1st to 15thDay
67%5%9%11%5%
1800
16th to endDay
71%46%10%6%
2210
April1st to 15thDay
71%47%11%41
2153
16th to endDay
63%46%15%9%
2346
May1st to 15thDay
61%49%17%7%
2512
16th to endDay
63%411%13%5%
2706
June1st to 15thDay
67%5%11%11%3
2700
16th to endDay
59%5%11%17%6%
2700
July1st to 15thDay
48%7%14%23%6%
2477
16th to endDay
57%7%11%18%5%
2486
August1st to 15thDay
55%7%15%17%4
2506
16th to endDay
57%6%15%16%4
2413
September1st to 15thDay
57%5%11%19%5%
2148
16th to endDay
57%6%15%14%6%
1980
October1st to 15thDay
57%6%13%15%6%1
1833
16th to endDay
75%36%11%3
1728
November1st to 15thDay
74%48%10%2
1676
16th to endDay
74%6%8%7%3
1404
December1st to 15thDay
81%5%6%5%1
1271
16th to endDay
82%45%5%2
1344
January1st to 15thNight
83%45%5%1
2539
16th to endNight
79%5%6%5%2
2688
February1st to 15thNight
80%6%6%6%
2418
16th to endNight
75%47%7%4
1903
March1st to 15thNight
68%5%9%12%4
2160
16th to endNight
69%48%11%4
2010
April1st to 15thNight
68%39%11%6%
1796
16th to endNight
65%47%14%8%
1613
May1st to 15thNight
59%410%17%7%
1440
16th to endNight
61%6%9%16%5%
1409
June1st to 15thNight
64%6%10%13%4
1260
16th to endNight
55%7%14%15%6%
1260
July1st to 15thNight
48%6%17%21%5%
1253
16th to endNight
52%7%14%20%5%
1419
August1st to 15thNight
53%8%16%18%3
1429
16th to endNight
51%8%17%18%3
1789
September1st to 15thNight
55%5%13%19%5%
1812
16th to endNight
56%6%15%15%5%
1980
October1st to 15thNight
58%6%13%14%6%
2127
16th to endNight
68%410%12%4
2496
November1st to 15thNight
70%5%8%13%1
2511
16th to endNight
74%5%8%7%3
2885
December1st to 15thNight
80%5%6%5%1
2726
16th to endNight
83%445%2
2880

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%23%34%12%5%1
240
16th to endDay
25%14%29%20%9%
256
February1st to 15thDay
23%20%28%21%41
236
16th to endDay
23%18%25%17%9%4
212
March1st to 15thDay
28%16%26%16%8%4
240
16th to endDay
28%16%26%16%10%1
278
April1st to 15thDay
28%24%21%17%7%1
270
16th to endDay
33%14%22%18%7%2
444
May1st to 15thDay
32%10%17%23%11%3
468
16th to endDay
33%10%24%19%9%3
519
June1st to 15thDay
36%7%21%19%11%2
495
16th to endDay
29%10%29%18%7%4
495
July1st to 15thDay
22%10%28%23%11%4
475
16th to endDay
24%7%25%26%12%2
514
August1st to 15thDay
22%7%27%24%13%3
493
16th to endDay
23%8%24%25%12%5%
448
September1st to 15thDay
32%9%33%16%7%
312
16th to endDay
27%15%31%17%6%1
269
October1st to 15thDay
26%18%26%17%9%2
270
16th to endDay
37%15%19%15%10%2
288
November1st to 15thDay
30%16%22%20%8%2
280
16th to endDay
29%22%22%17%7%1
285
December1st to 15thDay
26%20%31%15%5%
245
16th to endDay
30%19%25%17%5%1
256
January1st to 15thNight
25%19%32%17%4
750
16th to endNight
21%21%29%21%5%
800
February1st to 15thNight
23%18%30%21%6%
726
16th to endNight
23%15%28%20%9%2
631
March1st to 15thNight
25%18%26%20%8%
720
16th to endNight
25%15%28%22%7%
606
April1st to 15thNight
28%15%29%20%5%
539
16th to endNight
28%11%28%21%8%
540
May1st to 15thNight
27%10%24%26%9%
540
16th to endNight
34%9%24%24%8%
561
June1st to 15thNight
33%7%22%26%9%
540
16th to endNight
28%7%25%25%10%
540
July1st to 15thNight
20%10%30%27%10%
510
16th to endNight
24%6%26%30%12%
565
August1st to 15thNight
20%6%28%28%14%
539
16th to endNight
24%5%28%24%15%1
573
September1st to 15thNight
28%10%28%25%7%
540
16th to endNight
27%10%32%24%5%
538
October1st to 15thNight
26%14%27%23%6%1
665
16th to endNight
33%13%25%19%8%
816
November1st to 15thNight
33%14%23%20%8%
805
16th to endNight
30%18%28%18%3
825
December1st to 15thNight
28%18%28%18%5%
759
16th to endNight
28%17%27%20%5%1
800
Page generated at 2017-12-03 12:46:47. Version ac04

Copyright 2017 A. Danko


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