This page made possible by the sponsorship of: Jim Mazur.

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 2017-03-26.

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
27%
14476
18%
45284
8%
14445
39%
14445
19%
29550

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%
748
23%
1960
6%
748
33%
748
23%
1290
April1st to 15thNight
22%
658
18%
1646
5%
658
29%
658
19%
1170
April16th to endNight
25%
591
18%
1581
3%
591
34%
591
21%
1078
May1st to 15thNight
26%
495
17%
1485
6%
495
36%
495
15%
1033
May16th to endNight
30%
357
12%
1384
8%
357
38%
357
13%
915
June1st to 15thNight
32%
330
14%
1320
12%
330
43%
330
15%
886
June16th to endNight
50%
330
12%
1320
13%
330
58%
330
21%
756
July1st to 15thNight
43%
310
12%
1240
15%
310
47%
310
18%
769
July16th to endNight
48%
348
14%
1306
14%
326
58%
326
20%
802
August1st to 15thNight
49%
477
18%
1458
11%
475
54%
475
25%
915
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%
45697
Night
17%6%24424446%41%
45454
Cloud CoverDay
16%5%2442445%7%41%
45707
Night
17%6%24424446%41%
45459
TransparencyDay
40%6%13%22%15%2
45385
Night
43%5%12%21%15%2
45284
SeeingDay
17%19%26%22%10%3
5175
Night
18%24%25%22%8%1
14477

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
17%6%25%434335%42%
2150
April1st to 15thDay
22%5%2432335%5%41%
1972
16th to endDay
17%5%2342335%6%46%
2049
May1st to 15thDay
25%5%2442335%5%37%
2137
16th to endDay
17%434424448%41%
2387
June1st to 15thDay
23%5%2442445%8%33%
2310
16th to endDay
12%5%245%245%6%9%41%
2310
July1st to 15thDay
13%6%23435%5%6%10%38%
2310
16th to endDay
14%4244345%6%9%39%
2458
August1st to 15thDay
14%314425%5%6%8%40%
2150
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
16%6%34424335%45%
1960
April1st to 15thNight
20%7%25%423445%38%
1646
16th to endNight
20%5%25%42333442%
1581
May1st to 15thNight
20%6%35%335%446%36%
1485
16th to endNight
20%6%2442445%9%36%
1382
June1st to 15thNight
22%6%25%42435%6%36%
1320
16th to endNight
14%32332445%9%45%
1320
July1st to 15thNight
14%5%34436%6%5%8%38%
1320
16th to endNight
11%6%25%5%25%5%6%9%36%
1402
August1st to 15thNight
10%5%15%4346%7%8%41%
1468
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
16%6%34424445%42%
2150
April1st to 15thDay
21%434323446%41%
1972
16th to endDay
16%42342335%7%46%
2049
May1st to 15thDay
24%6%24424346%37%
2137
16th to endDay
16%5%24424447%42%
2387
June1st to 15thDay
22%6%2442345%8%33%
2310
16th to endDay
11%5%24435%46%8%43%
2310
July1st to 15thDay
12%4244246%6%9%40%
2310
16th to endDay
13%4244245%6%9%40%
2458
August1st to 15thDay
13%414335%5%6%9%42%
2150
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
16%6%24424345%45%
1959
April1st to 15thNight
19%7%25%433346%38%
1646
16th to endNight
20%5%25%413435%42%
1581
May1st to 15thNight
21%6%25%435%346%36%
1485
16th to endNight
20%6%2342445%9%36%
1382
June1st to 15thNight
22%6%24424346%36%
1320
16th to endNight
14%32342446%8%45%
1320
July1st to 15thNight
13%5%25%5%35%5%6%8%38%
1320
16th to endNight
11%6%35%435%6%5%10%37%
1402
August1st to 15thNight
10%4145%35%6%7%8%40%
1468
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
2150
April1st to 15thDay
42%5%12%19%16%3
1972
16th to endDay
36%5%10%23%19%4
2049
May1st to 15thDay
46%6%9%20%14%2
2137
16th to endDay
39%8%15%19%14%2
2391
June1st to 15thDay
46%7%13%20%10%1
2310
16th to endDay
34%8%16%25%13%1
2310
July1st to 15thDay
36%8%14%23%15%1
2161
16th to endDay
35%8%16%23%13%2
2291
August1st to 15thDay
34%8%17%23%16%
2136
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
39%410%20%19%5%
1960
April1st to 15thNight
46%410%20%14%2
1646
16th to endNight
44%48%20%18%4
1581
May1st to 15thNight
47%6%10%16%15%3
1485
16th to endNight
45%9%15%15%12%1
1384
June1st to 15thNight
47%7%12%17%12%2
1320
16th to endNight
35%7%16%25%15%
1320
July1st to 15thNight
40%8%13%22%14%
1240
16th to endNight
39%8%14%24%11%2
1306
August1st to 15thNight
34%10%14%23%15%2
1458
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
17%26%35%15%31
267
April1st to 15thDay
21%27%26%16%7%
210
16th to endDay
14%22%27%20%10%3
210
May1st to 15thDay
32%22%17%17%7%3
228
16th to endDay
19%18%22%23%13%1
267
June1st to 15thDay
20%19%26%16%14%3
255
16th to endDay
11%14%27%28%15%2
255
July1st to 15thDay
13%11%20%31%18%4
245
16th to endDay
11%14%23%33%12%3
270
August1st to 15thDay
13%9%20%36%14%5%
253
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
16%28%31%17%5%
748
April1st to 15thNight
21%27%26%20%3
658
16th to endNight
18%26%24%23%6%1
591
May1st to 15thNight
19%25%23%20%9%
495
16th to endNight
21%22%18%27%8%
358
June1st to 15thNight
21%22%17%26%11%
330
16th to endNight
13%18%13%39%14%
330
July1st to 15thNight
13%15%17%33%18%1
310
16th to endNight
12%19%13%37%15%1
348
August1st to 15thNight
12%11%19%38%17%1
477
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 2017-03-27 11:15:17. Version ac04

Copyright 2017 A. Danko


Deer Lake Clear Sky Chart | Charts Home