Eight Point Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eight Point Lake clear sky chart from 2005-11-05 to 2017-10-16.

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
35%
16134
14%
47313
9%
16092
40%
16092
20%
33366

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%
900
8%
2506
2%
895
19%
895
10%
2093
January16th to endNight
20%
960
8%
2688
3%
960
24%
960
12%
2181
February1st to 15thNight
20%
716
10%
2243
4%
716
25%
716
12%
1728
February16th to endNight
24%
631
12%
1893
6%
631
30%
631
13%
1455
March1st to 15thNight
30%
720
16%
2124
9%
720
35%
720
19%
1495
March16th to endNight
30%
744
18%
2088
9%
744
38%
744
22%
1437
April1st to 15thNight
28%
539
14%
1794
9%
539
36%
539
18%
1243
April16th to endNight
35%
540
19%
1620
9%
540
44%
540
25%
1074
May1st to 15thNight
39%
540
15%
1620
8%
540
45%
540
23%
1117
May16th to endNight
41%
562
17%
1548
9%
561
49%
561
30%
999
June1st to 15thNight
46%
540
14%
1440
8%
540
51%
540
32%
936
June16th to endNight
51%
540
14%
1440
8%
540
56%
540
34%
921
July1st to 15thNight
65%
510
17%
1360
14%
510
68%
510
44%
778
July16th to endNight
60%
564
17%
1417
11%
531
64%
531
40%
843
August1st to 15thNight
65%
539
22%
1593
17%
536
69%
536
38%
902
August16th to endNight
61%
573
22%
1787
19%
573
65%
573
34%
1033
September1st to 15thNight
58%
618
24%
1878
20%
618
63%
618
39%
1037
September16th to endNight
55%
717
23%
1980
18%
717
58%
717
32%
1245
October1st to 15thNight
42%
720
19%
2034
15%
720
47%
720
27%
1351
October16th to endNight
26%
708
12%
2286
7%
708
33%
708
15%
1668
November1st to 15thNight
32%
700
17%
2276
13%
700
38%
700
19%
1577
November16th to endNight
24%
720
9%
2340
5%
720
30%
720
11%
1803
December1st to 15thNight
16%
873
5%
2658
2%
873
20%
873
9%
2202
December16th to endNight
14%
960
8%
2700
1%
960
20%
960
10%
2248

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
14%9%47%6%35%45%7%32%
48104
Night
14%9%46%6%3445%7%33%
47481
Cloud CoverDay
14%9%47%6%35%45%7%32%
48113
Night
14%9%46%5%3445%7%34%
47486
TransparencyDay
50%6%11%20%10%1
47790
Night
48%6%12%20%10%1
47313
SeeingDay
17%8%28%25%14%6%
6093
Night
18%7%30%29%11%1
16138

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
14%16%7%13%9%6%5%445%12%
1432
16th to endDay
13%18%11%12%9%5%6%44310%
1536
February1st to 15thDay
14%13%6%11%11%46%45%6%17%
1618
16th to endDay
11%14%7%10%11%45%5%5%5%18%
1580
March1st to 15thDay
14%9%5%6%7%345%6%6%29%
1826
16th to endDay
15%9%48%6%3445%432%
2145
April1st to 15thDay
20%13%4441345%5%32%
2154
16th to endDay
16%9%36%5%245%5%5%34%
2340
May1st to 15thDay
18%7%35%5%2445%7%34%
2331
16th to endDay
11%6%245%245%5%8%40%
2564
June1st to 15thDay
11%7%25%5%25%5%6%7%38%
2520
16th to endDay
10%5%35%5%46%6%6%8%37%
2520
July1st to 15thDay
7%415%5%35%6%6%9%44%
2520
16th to endDay
9%425%5%36%5%6%9%41%
2655
August1st to 15thDay
8%5%25%7%35%6%6%9%39%
2356
16th to endDay
12%6%245%345%5%7%41%
2413
September1st to 15thDay
12%5%245%25%45%7%42%
2070
16th to endDay
11%5%26%5%36%45%9%39%
1980
October1st to 15thDay
19%8%36%5%34346%34%
1926
16th to endDay
21%12%38%5%35%45%5%22%
1605
November1st to 15thDay
15%10%46%6%3435%6%32%
1582
16th to endDay
21%16%6%8%6%35%345%18%
1620
December1st to 15thDay
17%14%10%12%8%24345%16%
1293
16th to endDay
21%18%8%10%6%34335%13%
1518
January1st to 15thNight
20%12%6%11%8%35%34417%
2506
16th to endNight
12%13%8%11%7%46%6%6%7%15%
2688
February1st to 15thNight
12%12%7%8%9%46%45%5%23%
2241
16th to endNight
14%12%5%8%8%46%446%23%
1893
March1st to 15thNight
15%8%46%6%2445%7%34%
2111
16th to endNight
15%7%36%5%25%447%37%
2088
April1st to 15thNight
19%8%37%42345%7%32%
1794
16th to endNight
17%7%24423347%40%
1620
May1st to 15thNight
14%5%35%6%4445%8%35%
1620
16th to endNight
10%6%25%43445%9%43%
1546
June1st to 15thNight
12%425%4245%5%9%43%
1440
16th to endNight
8%425%5%3445%8%46%
1440
July1st to 15thNight
6%21441446%9%54%
1440
16th to endNight
6%3144345%6%10%49%
1513
August1st to 15thNight
5%41333447%8%52%
1602
16th to endNight
10%324424447%52%
1787
September1st to 15thNight
11%41222345%6%55%
1878
16th to endNight
10%5%245%2445%7%47%
1980
October1st to 15thNight
18%6%24423446%41%
2034
16th to endNight
20%10%36%5%24446%29%
2286
November1st to 15thNight
14%11%36%6%2445%7%32%
2276
16th to endNight
18%15%37%6%35%5%5%6%21%
2340
December1st to 15thNight
19%14%6%9%8%35%445%17%
2658
16th to endNight
20%16%7%10%6%3445%6%14%
2700

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
15%16%7%13%9%6%4435%12%
1432
16th to endDay
13%17%11%12%9%5%6%43410%
1536
February1st to 15thDay
14%12%6%11%11%36%446%17%
1618
16th to endDay
11%14%6%11%10%5%5%5%5%5%18%
1580
March1st to 15thDay
14%10%47%7%4446%6%29%
1836
16th to endDay
15%9%48%7%3445%5%32%
2144
April1st to 15thDay
20%12%45%31345%6%31%
2154
16th to endDay
16%8%36%5%25%5%5%6%34%
2340
May1st to 15thDay
18%8%35%5%2445%7%34%
2331
16th to endDay
11%6%25%5%245%5%8%40%
2564
June1st to 15thDay
11%7%25%5%36%46%7%38%
2520
16th to endDay
11%4346%36%6%6%8%37%
2520
July1st to 15thDay
6%425%5%35%5%6%9%44%
2520
16th to endDay
9%4245%35%6%6%9%41%
2655
August1st to 15thDay
8%5%15%7%35%5%7%9%38%
2356
16th to endDay
13%6%25%5%3446%7%41%
2413
September1st to 15thDay
13%425%5%345%5%8%42%
2070
16th to endDay
11%5%26%6%45%45%8%40%
1980
October1st to 15thDay
18%9%26%6%34346%34%
1926
16th to endDay
22%11%48%6%3445%6%22%
1605
November1st to 15thDay
14%10%46%6%34347%32%
1582
16th to endDay
22%15%6%8%6%44445%18%
1620
December1st to 15thDay
17%14%9%13%7%34335%16%
1293
16th to endDay
21%18%7%10%6%34335%13%
1518
January1st to 15thNight
20%12%6%11%7%35%34418%
2506
16th to endNight
12%12%8%11%7%46%5%6%7%16%
2688
February1st to 15thNight
12%12%7%8%8%46%45%5%23%
2234
16th to endNight
14%12%48%8%46%5%46%23%
1893
March1st to 15thNight
16%8%47%5%3445%7%34%
2124
16th to endNight
15%6%46%5%2445%7%37%
2088
April1st to 15thNight
19%9%37%42335%7%32%
1794
16th to endNight
17%7%245%33447%40%
1620
May1st to 15thNight
14%6%26%6%445%5%7%37%
1619
16th to endNight
11%6%25%5%2445%9%43%
1546
June1st to 15thNight
11%425%5%15%45%8%43%
1440
16th to endNight
8%426%5%2446%9%45%
1440
July1st to 15thNight
6%3234235%6%9%54%
1440
16th to endNight
6%3235%25%46%10%49%
1513
August1st to 15thNight
5%4134335%6%8%52%
1602
16th to endNight
10%414323447%52%
1787
September1st to 15thNight
11%41221335%6%55%
1878
16th to endNight
10%5%244245%47%47%
1980
October1st to 15thNight
18%6%24423445%42%
2034
16th to endNight
20%10%46%5%34446%29%
2286
November1st to 15thNight
14%10%36%5%2445%7%33%
2276
16th to endNight
18%13%47%7%445%5%7%21%
2340
December1st to 15thNight
19%13%6%9%8%35%446%17%
2658
16th to endNight
20%15%6%11%6%2435%6%15%
2700

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%5%9%10%2
1433
16th to endDay
76%5%8%6%2
1536
February1st to 15thDay
66%6%9%13%3
1620
16th to endDay
64%6%9%12%6%
1580
March1st to 15thDay
52%6%11%19%8%
1836
16th to endDay
51%6%11%20%7%1
2145
April1st to 15thDay
53%49%19%12%
2154
16th to endDay
48%6%12%16%13%2
2340
May1st to 15thDay
47%6%11%22%10%2
2331
16th to endDay
39%6%14%25%13%
2568
June1st to 15thDay
42%6%12%24%13%
2520
16th to endDay
41%9%13%22%13%
2520
July1st to 15thDay
33%8%10%27%18%1
2371
16th to endDay
37%8%11%23%16%2
2488
August1st to 15thDay
38%8%11%27%12%1
2341
16th to endDay
40%7%11%23%15%2
2413
September1st to 15thDay
38%6%11%29%13%1
2070
16th to endDay
40%7%14%25%11%
1980
October1st to 15thDay
50%5%9%22%11%
1926
16th to endDay
60%6%14%13%4
1605
November1st to 15thDay
50%6%12%21%8%
1582
16th to endDay
67%5%10%11%4
1620
December1st to 15thDay
70%6%9%11%2
1293
16th to endDay
73%5%9%8%2
1518
January1st to 15thNight
68%5%8%12%5%
2506
16th to endNight
63%6%14%10%3
2688
February1st to 15thNight
60%6%9%16%6%
2243
16th to endNight
59%5%12%14%7%
1893
March1st to 15thNight
49%6%11%20%10%1
2124
16th to endNight
46%5%13%22%10%1
2088
April1st to 15thNight
50%49%19%14%
1794
16th to endNight
43%5%11%20%15%3
1620
May1st to 15thNight
44%7%11%21%12%2
1620
16th to endNight
37%6%11%26%15%2
1548
June1st to 15thNight
37%5%13%25%16%1
1440
16th to endNight
34%7%14%24%18%
1440
July1st to 15thNight
24%6%12%32%21%2
1360
16th to endNight
28%6%18%27%17%2
1417
August1st to 15thNight
27%6%14%34%16%
1593
16th to endNight
31%5%13%27%19%1
1787
September1st to 15thNight
27%5%13%33%18%
1878
16th to endNight
34%7%13%32%11%
1980
October1st to 15thNight
42%5%10%26%13%1
2034
16th to endNight
55%5%13%18%7%
2286
November1st to 15thNight
48%6%14%18%11%
2276
16th to endNight
61%5%14%14%3
2340
December1st to 15thNight
66%7%11%10%3
2658
16th to endNight
68%5%11%10%3
2700

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
21%10%43%23%2
90
16th to endDay
31%5%42%15%5%
96
February1st to 15thDay
26%20%40%10%3
90
16th to endDay
23%19%32%19%4
81
March1st to 15thDay
27%15%29%23%4
126
16th to endDay
26%5%29%25%10%2
288
April1st to 15thDay
29%8%30%21%9%1
270
16th to endDay
21%9%32%20%10%5%
270
May1st to 15thDay
24%12%24%25%7%6%
288
16th to endDay
14%11%30%25%13%4
464
June1st to 15thDay
13%8%34%29%10%3
495
16th to endDay
12%10%32%26%14%4
495
July1st to 15thDay
7%6%28%26%22%9%
475
16th to endDay
10%428%29%16%10%
515
August1st to 15thDay
10%119%25%27%15%
329
16th to endDay
18%314%29%20%13%
332
September1st to 15thDay
12%119%28%23%13%
315
16th to endDay
14%5%18%24%28%7%
314
October1st to 15thDay
25%5%23%31%11%1
315
16th to endDay
28%10%39%18%1
111
November1st to 15thDay
11%15%38%22%8%3
90
16th to endDay
31%15%35%13%4
90
December1st to 15thDay
24%29%26%14%31
61
16th to endDay
30%27%31%10%
93
January1st to 15thNight
25%11%35%19%6%
900
16th to endNight
17%8%38%28%5%
960
February1st to 15thNight
17%12%38%25%5%
719
16th to endNight
21%10%33%29%5%
631
March1st to 15thNight
18%10%34%26%9%
720
16th to endNight
16%9%36%28%7%1
744
April1st to 15thNight
22%10%33%26%5%
539
16th to endNight
22%6%33%28%8%1
540
May1st to 15thNight
16%6%31%35%9%
540
16th to endNight
12%5%31%32%16%1
563
June1st to 15thNight
14%428%36%15%1
540
16th to endNight
10%227%41%15%1
540
July1st to 15thNight
8%118%43%24%2
510
16th to endNight
7%124%40%23%1
564
August1st to 15thNight
7%19%46%23%2
539
16th to endNight
11%218%34%30%2
573
September1st to 15thNight
12%322%33%22%5%
618
16th to endNight
13%322%30%25%4
717
October1st to 15thNight
21%426%33%13%1
720
16th to endNight
27%9%32%23%7%
708
November1st to 15thNight
20%9%31%27%10%
700
16th to endNight
24%12%30%24%6%
720
December1st to 15thNight
25%11%36%23%2
873
16th to endNight
28%10%36%20%3
960
Page generated at 2017-10-17 16:35:22. Version ac04

Copyright 2017 A. Danko


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