TheDamObservatory-Lake Tschida
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the TheDamObservatory-Lake Tschida clear sky chart from 2005-11-05 to 2017-07-28.

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
40%
16043
17%
46413
10%
16002
46%
16002
28%
29713

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
27%
898
13%
2506
6%
895
33%
895
20%
1768
January16th to endNight
26%
960
14%
2688
6%
960
33%
960
20%
1907
February1st to 15thNight
30%
816
10%
2362
5%
816
35%
816
18%
1717
February16th to endNight
35%
632
15%
1894
9%
632
42%
632
24%
1268
March1st to 15thNight
32%
720
13%
2160
7%
720
38%
720
21%
1480
March16th to endNight
36%
589
13%
2026
9%
589
43%
589
20%
1350
April1st to 15thNight
33%
539
18%
1798
11%
539
46%
539
25%
1099
April16th to endNight
36%
540
16%
1636
13%
540
42%
540
23%
1108
May1st to 15thNight
45%
540
16%
1518
9%
540
49%
540
31%
968
May16th to endNight
44%
563
13%
1498
6%
561
45%
561
30%
974
June1st to 15thNight
45%
540
11%
1302
5%
540
49%
540
36%
850
June16th to endNight
54%
540
13%
1302
7%
540
56%
540
51%
742
July1st to 15thNight
60%
510
15%
1360
9%
510
62%
510
51%
728
July16th to endNight
66%
555
21%
1392
12%
522
67%
522
56%
719
August1st to 15thNight
62%
494
25%
1350
16%
491
67%
491
48%
734
August16th to endNight
60%
525
26%
1663
23%
525
70%
525
46%
826
September1st to 15thNight
58%
495
25%
1671
23%
495
67%
495
40%
855
September16th to endNight
51%
492
27%
1815
24%
492
60%
492
35%
919
October1st to 15thNight
42%
580
25%
1900
19%
580
48%
580
26%
1141
October16th to endNight
42%
880
21%
2288
10%
880
47%
880
30%
1490
November1st to 15thNight
38%
875
24%
2275
10%
875
45%
875
32%
1443
November16th to endNight
33%
900
19%
2519
9%
900
41%
900
25%
1667
December1st to 15thNight
30%
900
11%
2700
6%
900
36%
900
18%
1934
December16th to endNight
28%
960
15%
2790
7%
960
36%
960
17%
2026

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
10%7%36%5%3445%7%43%
47240
Night
8%7%36%5%3445%7%43%
46580
Cloud CoverDay
9%7%36%5%2445%7%43%
47249
Night
8%7%36%5%3445%7%43%
46584
Cloud CoverDay
9%7%36%5%3445%7%43%
47250
Night
8%7%36%5%3445%7%43%
46585
Cloud CoverDay
10%7%36%5%3445%7%42%
47248
Night
8%7%36%5%3445%7%43%
46585
TransparencyDay
40%5%15%25%11%1
46924
Night
39%5%15%25%12%1
46413
SeeingDay
13%7%29%31%15%2
5939
Night
11%8%31%35%11%1
16050

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
5%9%5%9%6%35%45%7%36%
1432
16th to endDay
5%9%6%8%8%45%5%5%6%32%
1536
February1st to 15thDay
9%9%5%8%8%45%45%5%32%
1509
16th to endDay
5%11%7%12%9%35%5%46%27%
1580
March1st to 15thDay
8%8%5%8%6%34447%36%
1790
16th to endDay
14%11%47%6%35%45%6%30%
2194
April1st to 15thDay
10%7%47%5%3445%7%38%
2150
16th to endDay
17%9%36%5%2445%6%33%
2323
May1st to 15thDay
13%9%26%424446%41%
2430
16th to endDay
15%7%35%5%25%5%5%8%36%
2616
June1st to 15thDay
15%4245%3445%7%41%
2653
16th to endDay
6%3135%245%5%8%52%
2653
July1st to 15thDay
5%21332446%9%55%
2520
16th to endDay
5%21342445%8%56%
2613
August1st to 15thDay
7%3144245%6%8%51%
2270
16th to endDay
7%423423336%58%
2187
September1st to 15thDay
8%42443445%5%53%
1958
16th to endDay
11%413421235%58%
1815
October1st to 15thDay
12%6%35%5%23346%47%
1716
16th to endDay
11%9%3442335%8%41%
1584
November1st to 15thDay
8%7%345%25%45%6%47%
1583
16th to endDay
6%10%5%9%6%3436%8%35%
1437
December1st to 15thDay
7%11%5%8%8%36%5%5%7%31%
1260
16th to endDay
10%11%49%6%4445%8%29%
1431
January1st to 15thNight
6%9%5%8%8%36%5%5%6%34%
2506
16th to endNight
411%5%9%6%45%5%5%8%33%
2688
February1st to 15thNight
9%8%5%9%7%46%5%5%7%31%
2359
16th to endNight
6%9%48%7%345%5%6%38%
1894
March1st to 15thNight
6%8%47%6%46%5%5%6%37%
2147
16th to endNight
13%9%36%6%245%6%6%35%
2026
April1st to 15thNight
8%7%26%435%5%7%7%40%
1798
16th to endNight
13%6%45%5%35%5%5%7%37%
1636
May1st to 15thNight
10%5%25%5%35%45%8%42%
1518
16th to endNight
13%4145%245%7%9%41%
1497
June1st to 15thNight
10%32343447%8%45%
1302
16th to endNight
5%21321446%9%57%
1302
July1st to 15thNight
321332235%8%61%
1440
16th to endNight
412213448%65%
1488
August1st to 15thNight
431333345%7%60%
1358
16th to endNight
5%31231436%6%62%
1663
September1st to 15thNight
7%414312348%58%
1671
16th to endNight
9%413313247%57%
1815
October1st to 15thNight
14%5%24324447%46%
1900
16th to endNight
10%8%346%2445%7%43%
2288
November1st to 15thNight
7%6%35%4245%6%8%45%
2275
16th to endNight
7%7%37%6%345%6%8%39%
2519
December1st to 15thNight
8%10%5%9%7%35%5%46%32%
2700
16th to endNight
10%13%5%8%6%34446%31%
2790

Percentage Cloud Cover NW (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
5%9%5%9%6%35%46%7%36%
1433
16th to endDay
5%9%5%8%8%36%5%5%7%32%
1536
February1st to 15thDay
9%9%5%8%8%36%36%6%32%
1509
16th to endDay
5%11%7%12%9%35%5%5%6%28%
1580
March1st to 15thDay
7%9%47%7%35%447%37%
1800
16th to endDay
15%11%47%6%35%446%30%
2192
April1st to 15thDay
10%7%47%425%45%7%38%
2150
16th to endDay
17%9%35%5%2446%6%33%
2323
May1st to 15thDay
13%8%35%42345%6%41%
2430
16th to endDay
15%6%26%5%345%6%8%36%
2616
June1st to 15thDay
15%425%5%3445%7%40%
2653
16th to endDay
6%3144245%5%8%53%
2653
July1st to 15thDay
5%2133245%5%9%54%
2520
16th to endDay
5%21343445%8%56%
2613
August1st to 15thDay
7%31442446%8%51%
2270
16th to endDay
7%423413336%58%
2187
September1st to 15thDay
8%414424446%53%
1958
16th to endDay
11%413312235%59%
1815
October1st to 15thDay
13%6%345%23346%47%
1716
16th to endDay
11%9%35%42435%8%42%
1584
November1st to 15thDay
8%7%345%24447%46%
1583
16th to endDay
6%9%49%7%3436%8%35%
1437
December1st to 15thDay
6%11%6%8%7%45%5%6%6%32%
1260
16th to endDay
10%12%49%6%4435%7%30%
1431
January1st to 15thNight
6%8%5%8%8%35%5%5%7%34%
2506
16th to endNight
410%5%9%6%35%5%5%8%32%
2688
February1st to 15thNight
9%8%5%9%8%35%5%5%7%30%
2352
16th to endNight
5%9%5%7%8%25%45%6%38%
1894
March1st to 15thNight
6%9%47%7%46%5%5%5%37%
2160
16th to endNight
13%9%45%6%245%6%6%35%
2024
April1st to 15thNight
8%7%35%5%25%6%7%7%40%
1798
16th to endNight
14%5%45%6%35%45%7%37%
1636
May1st to 15thNight
10%6%26%435%45%8%42%
1517
16th to endNight
13%5%25%43446%9%41%
1498
June1st to 15thNight
10%42442447%9%45%
1302
16th to endNight
431222346%8%58%
1302
July1st to 15thNight
321342335%8%61%
1440
16th to endNight
4112213448%65%
1488
August1st to 15thNight
431233445%6%60%
1358
16th to endNight
5%22314447%61%
1663
September1st to 15thNight
7%323312348%58%
1671
16th to endNight
10%414312247%57%
1815
October1st to 15thNight
14%5%13423446%46%
1900
16th to endNight
9%8%25%5%3345%8%43%
2288
November1st to 15thNight
7%6%25%42446%7%46%
2275
16th to endNight
7%7%36%6%345%6%8%39%
2519
December1st to 15thNight
7%11%5%8%7%36%45%6%32%
2700
16th to endNight
10%12%5%8%7%345%46%31%
2790

Percentage Cloud Cover SW (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
5%9%5%9%6%35%45%7%36%
1432
16th to endDay
5%10%5%9%8%45%5%5%7%32%
1536
February1st to 15thDay
9%9%5%9%8%35%45%6%32%
1509
16th to endDay
5%11%6%12%10%35%446%28%
1580
March1st to 15thDay
7%9%5%8%6%35%447%37%
1800
16th to endDay
14%11%47%7%25%447%30%
2194
April1st to 15thDay
10%7%47%435%45%7%38%
2150
16th to endDay
17%9%35%5%2445%6%33%
2323
May1st to 15thDay
13%9%25%424446%41%
2430
16th to endDay
15%6%25%5%345%6%8%36%
2616
June1st to 15thDay
15%5%245%3445%7%40%
2653
16th to endDay
6%4135%2445%9%52%
2653
July1st to 15thDay
5%2133245%6%8%55%
2520
16th to endDay
5%21343445%8%56%
2613
August1st to 15thDay
7%31433446%8%51%
2270
16th to endDay
7%423423236%58%
2187
September1st to 15thDay
8%42443435%6%53%
1958
16th to endDay
11%5%13421235%58%
1815
October1st to 15thDay
13%6%245%23346%47%
1716
16th to endDay
11%8%4442335%8%41%
1584
November1st to 15thDay
8%7%345%24446%47%
1583
16th to endDay
6%10%48%7%3436%8%35%
1437
December1st to 15thDay
6%11%6%8%7%35%5%5%6%32%
1260
16th to endDay
10%11%5%9%7%4445%7%29%
1431
January1st to 15thNight
6%8%5%8%8%36%5%5%6%34%
2506
16th to endNight
411%5%9%6%45%5%5%8%33%
2688
February1st to 15thNight
9%8%5%9%7%45%5%5%7%30%
2352
16th to endNight
5%9%5%7%7%4445%7%38%
1894
March1st to 15thNight
6%8%5%7%6%46%5%6%6%37%
2160
16th to endNight
13%9%35%6%2446%7%35%
2026
April1st to 15thNight
8%7%26%5%25%6%7%7%40%
1798
16th to endNight
13%6%46%5%35%45%7%37%
1636
May1st to 15thNight
10%6%25%5%25%5%5%8%42%
1517
16th to endNight
13%5%135%3447%8%41%
1497
June1st to 15thNight
10%32443447%8%45%
1302
16th to endNight
5%31222347%8%58%
1302
July1st to 15thNight
321342235%8%61%
1440
16th to endNight
4112313448%65%
1488
August1st to 15thNight
431233345%7%60%
1358
16th to endNight
5%31132335%6%62%
1663
September1st to 15thNight
7%323312348%58%
1671
16th to endNight
9%413313237%57%
1815
October1st to 15thNight
14%6%13423446%46%
1900
16th to endNight
9%8%25%5%2445%8%42%
2288
November1st to 15thNight
7%6%25%4245%6%8%45%
2275
16th to endNight
7%7%36%7%35%46%8%39%
2519
December1st to 15thNight
8%11%5%9%7%45%5%46%32%
2700
16th to endNight
10%12%5%8%6%3445%6%31%
2790

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
5%10%5%10%5%35%36%8%36%
1432
16th to endDay
5%10%6%9%7%45%6%47%32%
1536
February1st to 15thDay
9%9%5%8%8%45%5%45%32%
1509
16th to endDay
6%11%7%12%8%36%35%6%28%
1580
March1st to 15thDay
8%8%5%8%7%34447%37%
1800
16th to endDay
15%11%47%6%35%446%30%
2192
April1st to 15thDay
11%7%37%5%3445%8%38%
2150
16th to endDay
18%8%36%5%3445%6%32%
2323
May1st to 15thDay
14%8%35%424346%41%
2430
16th to endDay
16%6%25%5%345%6%7%36%
2616
June1st to 15thDay
16%4245%35%45%7%41%
2653
16th to endDay
7%32333446%8%52%
2653
July1st to 15thDay
5%21343446%8%55%
2520
16th to endDay
5%21342446%7%56%
2613
August1st to 15thDay
8%32332445%8%52%
2270
16th to endDay
8%424312246%58%
2187
September1st to 15thDay
9%424423345%53%
1958
16th to endDay
11%5%13312235%58%
1815
October1st to 15thDay
13%6%25%5%14346%46%
1716
16th to endDay
12%8%3442346%7%41%
1584
November1st to 15thDay
9%6%35%5%2345%6%47%
1583
16th to endDay
6%11%48%7%2436%8%35%
1437
December1st to 15thDay
7%10%5%8%8%35%5%5%7%31%
1260
16th to endDay
10%11%49%6%5%335%7%30%
1431
January1st to 15thNight
7%9%5%8%6%36%45%7%34%
2506
16th to endNight
411%5%8%6%445%6%8%33%
2688
February1st to 15thNight
10%7%5%9%7%35%5%5%7%30%
2352
16th to endNight
6%9%47%6%4445%7%38%
1894
March1st to 15thNight
7%8%47%6%36%5%5%6%36%
2160
16th to endNight
13%9%36%425%45%7%35%
2026
April1st to 15thNight
8%7%26%425%6%7%7%41%
1798
16th to endNight
14%7%35%5%345%5%6%37%
1636
May1st to 15thNight
10%6%24435%46%8%42%
1517
16th to endNight
14%424425%5%6%8%42%
1497
June1st to 15thNight
10%4244245%7%7%46%
1302
16th to endNight
5%21322347%8%58%
1302
July1st to 15thNight
42331335%7%62%
1440
16th to endNight
5%1221336%8%65%
1488
August1st to 15thNight
431242445%7%60%
1358
16th to endNight
5%21332345%6%62%
1663
September1st to 15thNight
8%313312347%58%
1671
16th to endNight
10%414313247%57%
1815
October1st to 15thNight
15%5%13333347%46%
1900
16th to endNight
10%8%25%42445%7%43%
2288
November1st to 15thNight
8%6%3442445%8%45%
2275
16th to endNight
7%8%36%6%35%5%6%8%39%
2519
December1st to 15thNight
8%11%5%9%7%35%5%5%6%31%
2700
16th to endNight
10%12%5%8%7%3445%6%30%
2790

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
46%419%20%8%
1433
16th to endDay
50%7%15%19%7%
1536
February1st to 15thDay
52%415%20%7%
1510
16th to endDay
55%413%18%7%
1580
March1st to 15thDay
47%5%15%22%8%
1800
16th to endDay
54%417%19%3
2194
April1st to 15thDay
43%416%25%9%
2150
16th to endDay
50%5%13%21%8%1
2323
May1st to 15thDay
43%412%27%12%
2430
16th to endDay
45%5%16%23%8%
2620
June1st to 15thDay
42%5%17%25%8%
2653
16th to endDay
28%6%19%30%13%1
2653
July1st to 15thDay
24%5%15%32%15%5%
2371
16th to endDay
25%5%14%31%19%4
2446
August1st to 15thDay
28%5%16%25%18%5%
2254
16th to endDay
28%311%29%22%4
2187
September1st to 15thDay
31%413%32%15%2
1958
16th to endDay
30%310%35%19%1
1815
October1st to 15thDay
38%315%25%14%2
1716
16th to endDay
40%5%16%24%11%1
1584
November1st to 15thDay
37%414%27%15%1
1583
16th to endDay
46%5%18%19%9%1
1437
December1st to 15thDay
51%6%14%21%5%
1260
16th to endDay
53%416%18%6%
1431
January1st to 15thNight
48%5%16%18%9%1
2506
16th to endNight
48%6%16%21%6%1
2688
February1st to 15thNight
52%414%18%7%
2362
16th to endNight
45%415%22%10%
1894
March1st to 15thNight
46%5%14%24%8%
2160
16th to endNight
46%5%18%21%7%
2026
April1st to 15thNight
38%6%13%27%12%2
1798
16th to endNight
45%5%13%20%12%1
1636
May1st to 15thNight
37%5%13%29%14%
1518
16th to endNight
37%6%19%24%10%
1498
June1st to 15thNight
33%7%17%31%9%1
1302
16th to endNight
22%5%21%32%16%2
1302
July1st to 15thNight
21%315%35%16%6%
1360
16th to endNight
17%414%35%22%6%
1392
August1st to 15thNight
22%5%15%28%21%6%
1350
16th to endNight
22%410%34%24%5%
1663
September1st to 15thNight
25%412%33%19%3
1671
16th to endNight
28%311%33%20%1
1815
October1st to 15thNight
37%412%27%16%1
1900
16th to endNight
39%314%27%12%1
2288
November1st to 15thNight
35%5%13%25%17%2
2275
16th to endNight
41%6%18%20%11%1
2519
December1st to 15thNight
52%5%16%20%5%
2700
16th to endNight
53%413%20%6%
2790

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
13%10%31%24%12%8%
90
16th to endDay
8%17%26%27%10%10%
96
February1st to 15thDay
16%7%50%23%2
90
16th to endDay
17%7%28%30%14%1
81
March1st to 15thDay
17%8%38%24%6%3
90
16th to endDay
15%7%35%29%9%3
192
April1st to 15thDay
14%17%35%25%6%
269
16th to endDay
22%9%26%24%15%2
433
May1st to 15thDay
17%9%29%26%14%2
468
16th to endDay
17%5%29%30%14%2
517
June1st to 15thDay
15%8%28%29%15%2
495
16th to endDay
9%9%31%34%13%1
495
July1st to 15thDay
6%427%38%20%2
475
16th to endDay
7%425%42%18%2
500
August1st to 15thDay
9%226%38%20%2
418
16th to endDay
8%5%23%35%23%4
355
September1st to 15thDay
12%7%29%31%15%3
233
16th to endDay
11%336%31%15%2
90
October1st to 15thDay
17%10%34%23%12%2
90
16th to endDay
22%7%25%30%10%4
96
November1st to 15thDay
11%237%25%17%5%
90
16th to endDay
23%7%30%28%8%1
90
December1st to 15thDay
14%11%40%20%13%1
90
16th to endDay
13%10%45%19%10%
96
January1st to 15thNight
11%12%37%29%8%1
900
16th to endNight
10%13%39%27%8%
960
February1st to 15thNight
13%10%32%31%10%1
821
16th to endNight
9%6%35%34%11%1
632
March1st to 15thNight
10%10%36%29%10%2
720
16th to endNight
18%432%34%8%
589
April1st to 15thNight
11%7%38%32%8%
539
16th to endNight
17%7%30%29%14%
540
May1st to 15thNight
14%6%28%38%11%
540
16th to endNight
16%428%36%13%
563
June1st to 15thNight
12%5%30%39%11%
540
16th to endNight
7%5%29%44%13%
540
July1st to 15thNight
5%227%46%17%
510
16th to endNight
4123%50%18%
555
August1st to 15thNight
6%124%51%15%
494
16th to endNight
5%327%44%17%2
525
September1st to 15thNight
9%424%44%15%2
495
16th to endNight
11%428%36%17%1
492
October1st to 15thNight
18%10%24%35%11%
580
16th to endNight
15%8%27%35%12%1
880
November1st to 15thNight
10%11%34%31%10%1
875
16th to endNight
11%10%36%31%9%
900
December1st to 15thNight
13%10%33%33%9%1
900
16th to endNight
15%11%29%31%10%
960
Page generated at 2017-07-29 08:19:10. Version ac04

Copyright 2017 A. Danko


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