Turtle Beach Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Turtle Beach Observatory clear sky chart from 2005-11-05 to 2018-01-20.

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
44%
15990
24%
48403
15%
15944
52%
15944
27%
29123

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
25%
975
24%
2522
8%
970
35%
970
23%
1646
January16th to endNight
24%
985
26%
2561
8%
985
35%
985
25%
1704
February1st to 15thNight
26%
861
24%
2268
7%
858
36%
858
25%
1466
February16th to endNight
20%
496
27%
1758
8%
496
38%
496
18%
1080
March1st to 15thNight
25%
540
25%
1980
13%
540
39%
540
18%
1209
March16th to endNight
34%
576
21%
2112
14%
576
44%
576
23%
1217
April1st to 15thNight
30%
539
23%
1860
15%
539
43%
539
25%
1070
April16th to endNight
34%
540
22%
1800
14%
540
47%
540
22%
1083
May1st to 15thNight
31%
539
18%
1788
12%
539
43%
539
21%
1099
May16th to endNight
50%
563
25%
1684
19%
561
61%
561
33%
944
June1st to 15thNight
62%
540
19%
1620
18%
540
67%
540
34%
879
June16th to endNight
66%
540
20%
1620
19%
540
71%
540
33%
943
July1st to 15thNight
74%
510
17%
1530
20%
510
75%
510
36%
880
July16th to endNight
71%
564
18%
1594
21%
531
76%
531
34%
940
August1st to 15thNight
78%
539
23%
1670
26%
536
80%
536
43%
864
August16th to endNight
64%
573
15%
1910
17%
573
66%
573
21%
1260
September1st to 15thNight
68%
540
20%
1833
21%
540
70%
540
29%
1074
September16th to endNight
66%
550
29%
1993
28%
550
71%
550
28%
1100
October1st to 15thNight
63%
720
30%
2160
24%
720
66%
720
39%
1159
October16th to endNight
55%
768
37%
2304
24%
768
65%
768
40%
1212
November1st to 15thNight
44%
760
28%
2280
18%
760
52%
760
29%
1326
November16th to endNight
37%
780
33%
2340
16%
780
53%
780
27%
1353
December1st to 15thNight
30%
952
25%
2512
10%
952
40%
952
22%
1700
December16th to endNight
25%
1040
19%
2704
7%
1040
34%
1040
19%
1915

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
12%5%25%5%35%5%5%7%41%
49117
Night
11%5%2442445%7%48%
48602
TransparencyDay
40%6%11%18%17%6%
48817
Night
34%5%12%19%19%8%
48406
SeeingDay
10%11%14%22%27%13%
5879
Night
12%19%19%26%18%3
15991

By Month

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%6%2332224446%
1746
16th to endDay
21%5%2431333444%
1767
February1st to 15thDay
18%8%3442323444%
1590
16th to endDay
18%7%25%5%23435%42%
1725
March1st to 15thDay
22%7%35%413345%40%
1980
16th to endDay
13%7%36%5%33346%42%
2110
April1st to 15thDay
12%5%36%42445%7%42%
2088
16th to endDay
12%5%35%435%45%7%40%
2160
May1st to 15thDay
12%6%36%7%35%5%6%8%35%
2160
16th to endDay
8%4246%46%6%7%9%37%
2430
June1st to 15thDay
6%325%7%5%7%6%8%10%35%
2340
16th to endDay
6%5%36%7%5%8%7%6%10%32%
2340
July1st to 15thDay
8%425%7%36%6%7%10%36%
2340
16th to endDay
7%426%8%48%8%7%9%31%
2466
August1st to 15thDay
5%3145%47%6%8%11%42%
2280
16th to endDay
11%5%26%7%5%6%7%7%9%30%
2292
September1st to 15thDay
12%435%6%345%5%7%40%
2124
16th to endDay
7%4145%36%5%5%7%46%
1953
October1st to 15thDay
8%314423445%56%
1800
16th to endDay
12%422212235%58%
1920
November1st to 15thDay
9%5%25%5%2445%6%48%
1908
16th to endDay
13%5%14423335%50%
1950
December1st to 15thDay
18%10%2442343342%
1776
16th to endDay
19%10%36%5%23345%35%
1872
January1st to 15thNight
17%6%24423245%46%
2522
16th to endNight
19%7%23412335%45%
2561
February1st to 15thNight
15%6%24314235%48%
2261
16th to endNight
17%7%25%422335%45%
1758
March1st to 15thNight
20%6%23323336%43%
1980
16th to endNight
12%6%23423347%48%
2112
April1st to 15thNight
10%424335%45%7%48%
1860
16th to endNight
11%324435%446%47%
1800
May1st to 15thNight
9%6%245%445%6%8%41%
1787
16th to endNight
7%3144135%5%11%51%
1683
June1st to 15thNight
321342446%10%55%
1620
16th to endNight
5%213325%6%8%11%48%
1620
July1st to 15thNight
5%223425%5%6%12%46%
1620
16th to endNight
43235%35%6%8%12%44%
1702
August1st to 15thNight
211232447%13%55%
1680
16th to endNight
10%4245%46%6%7%9%37%
1910
September1st to 15thNight
8%42443445%8%49%
1833
16th to endNight
8%5%2432445%7%52%
1993
October1st to 15thNight
6%31342435%6%58%
2160
16th to endNight
11%31221233463%
2304
November1st to 15thNight
10%424424346%53%
2280
16th to endNight
12%5%24423235%53%
2340
December1st to 15thNight
18%8%35%323236%42%
2512
16th to endNight
18%10%36%423345%38%
2704

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
41%35%17%22%9%
1747
16th to endDay
42%35%14%22%10%
1767
February1st to 15thDay
44%26%16%19%9%
1591
16th to endDay
45%46%14%20%9%
1725
March1st to 15thDay
47%46%15%19%6%
1980
16th to endDay
44%37%15%23%4
2112
April1st to 15thDay
40%49%19%17%7%
2088
16th to endDay
42%5%11%16%17%6%
2160
May1st to 15thDay
45%6%11%15%13%7%
2160
16th to endDay
38%8%13%24%12%1
2434
June1st to 15thDay
39%9%14%21%15%
2340
16th to endDay
44%8%16%18%10%1
2340
July1st to 15thDay
39%8%19%22%9%1
2201
16th to endDay
42%11%17%21%6%
2311
August1st to 15thDay
31%9%20%27%10%
2266
16th to endDay
46%9%17%17%8%
2292
September1st to 15thDay
41%6%15%17%12%5%
2124
16th to endDay
35%5%12%19%19%6%
1953
October1st to 15thDay
29%5%9%20%20%14%
1800
16th to endDay
29%2415%32%15%
1920
November1st to 15thDay
35%6%10%16%23%7%
1908
16th to endDay
36%35%13%29%11%
1950
December1st to 15thDay
46%39%17%16%7%
1776
16th to endDay
51%36%17%16%5%
1872
January1st to 15thNight
41%26%16%22%10%
2522
16th to endNight
42%35%15%21%11%
2561
February1st to 15thNight
39%37%17%20%12%
2270
16th to endNight
43%26%16%18%12%
1758
March1st to 15thNight
42%38%15%20%9%
1980
16th to endNight
35%5%12%17%22%6%
2112
April1st to 15thNight
33%5%10%22%16%10%
1860
16th to endNight
37%6%10%18%17%9%
1800
May1st to 15thNight
37%7%12%16%16%8%
1788
16th to endNight
28%5%17%26%20%1
1685
June1st to 15thNight
22%9%17%31%18%1
1620
16th to endNight
26%10%20%24%16%
1620
July1st to 15thNight
27%8%29%24%10%
1530
16th to endNight
26%10%28%23%9%
1594
August1st to 15thNight
18%9%27%30%13%
1670
16th to endNight
40%10%20%17%9%2
1910
September1st to 15thNight
32%8%17%20%13%7%
1833
16th to endNight
31%6%10%19%22%9%
1993
October1st to 15thNight
24%6%11%20%22%14%
2160
16th to endNight
26%25%15%30%19%
2304
November1st to 15thNight
32%5%10%18%24%8%
2280
16th to endNight
33%36%14%27%15%
2340
December1st to 15thNight
44%38%18%16%8%
2512
16th to endNight
49%37%16%17%6%
2704

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
20%9%37%20%11%
135
16th to endDay
21%11%41%18%5%1
109
February1st to 15thDay
12%17%28%36%4
90
16th to endDay
14%14%43%22%4
81
March1st to 15thDay
20%16%41%15%6%
90
16th to endDay
17%7%28%32%12%2
96
April1st to 15thDay
13%19%28%21%14%1
207
16th to endDay
15%21%18%26%14%2
270
May1st to 15thDay
16%14%25%26%14%2
297
16th to endDay
8%16%20%29%20%4
517
June1st to 15thDay
6%13%8%27%36%7%
495
16th to endDay
8%13%6%22%33%15%
495
July1st to 15thDay
5%9%323%40%18%
475
16th to endDay
412%213%40%26%
515
August1st to 15thDay
5%8%212%46%26%
433
16th to endDay
13%6%414%32%28%
332
September1st to 15thDay
5%5%6%15%34%32%
279
16th to endDay
3218%50%25%
135
October1st to 15thDay
210%29%32%24%
135
16th to endDay
17%6%18%18%25%13%
144
November1st to 15thDay
14%120%41%20%2
135
16th to endDay
15%6%28%27%17%4
135
December1st to 15thDay
27%227%22%10%8%
135
16th to endDay
22%12%34%28%2
144
January1st to 15thNight
19%24%26%22%6%
975
16th to endNight
16%25%30%22%4
985
February1st to 15thNight
16%25%28%24%5%
861
16th to endNight
19%26%31%20%2
496
March1st to 15thNight
19%23%28%24%3
540
16th to endNight
12%22%27%25%10%
576
April1st to 15thNight
10%22%33%23%10%
539
16th to endNight
11%23%27%24%12%
540
May1st to 15thNight
11%24%28%25%8%1
540
16th to endNight
6%18%19%31%19%4
563
June1st to 15thNight
316%10%36%29%3
540
16th to endNight
417%6%31%32%6%
540
July1st to 15thNight
311%333%38%9%
510
16th to endNight
217%223%40%13%
564
August1st to 15thNight
39%229%46%9%
539
16th to endNight
10%9%425%37%12%
573
September1st to 15thNight
8%9%5%25%40%10%
540
16th to endNight
11%9%5%26%37%10%
550
October1st to 15thNight
6%11%12%33%28%7%
720
16th to endNight
11%12%17%31%23%3
768
November1st to 15thNight
10%18%22%28%17%1
760
16th to endNight
14%22%23%26%13%
780
December1st to 15thNight
21%23%21%24%8%
952
16th to endNight
21%25%23%23%5%
1040
Page generated at 2018-01-21 11:19:27. Version ac04

Copyright 2018 A. Danko


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