Dogshead
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dogshead clear sky chart from 2005-11-05 to 2018-02-13.

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
47%
16130
23%
48773
15%
16089
56%
16089
27%
30337

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%
780
23%
2522
10%
776
43%
776
21%
1563
January16th to endNight
26%
832
26%
2688
12%
832
44%
832
23%
1652
February1st to 15thNight
31%
750
26%
2255
11%
749
46%
749
26%
1381
February16th to endNight
25%
631
25%
1893
9%
631
42%
631
25%
1178
March1st to 15thNight
32%
720
24%
2046
12%
720
43%
720
26%
1316
March16th to endNight
38%
768
21%
2112
11%
768
45%
768
29%
1325
April1st to 15thNight
42%
665
25%
1923
15%
665
53%
665
34%
1122
April16th to endNight
49%
540
24%
1675
16%
540
57%
540
30%
1007
May1st to 15thNight
48%
540
19%
1620
10%
540
55%
540
27%
1034
May16th to endNight
59%
561
20%
1683
16%
561
62%
561
30%
1045
June1st to 15thNight
65%
540
16%
1620
13%
540
68%
540
28%
1051
June16th to endNight
71%
540
17%
1620
14%
540
73%
540
32%
996
July1st to 15thNight
69%
510
11%
1530
9%
510
69%
510
25%
1034
July16th to endNight
73%
564
16%
1595
14%
531
76%
531
26%
1050
August1st to 15thNight
66%
539
16%
1609
14%
536
67%
536
25%
1074
August16th to endNight
66%
573
18%
1896
20%
573
66%
573
23%
1274
September1st to 15thNight
61%
720
17%
1980
16%
720
62%
720
26%
1322
September16th to endNight
58%
717
25%
1980
19%
717
63%
717
31%
1265
October1st to 15thNight
55%
720
30%
2010
24%
720
62%
720
35%
1194
October16th to endNight
52%
768
35%
2304
26%
768
65%
768
38%
1256
November1st to 15thNight
51%
760
29%
2438
25%
760
62%
760
35%
1346
November16th to endNight
41%
780
28%
2535
20%
780
54%
780
29%
1447
December1st to 15thNight
35%
780
23%
2535
14%
780
48%
780
22%
1590
December16th to endNight
30%
832
21%
2704
12%
832
42%
832
18%
1815

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%424435%45%7%42%
49260
Night
13%42442445%7%46%
48973
TransparencyDay
40%6%11%18%18%5%
48961
Night
36%6%10%20%19%6%
48776
SeeingDay
17%6%19%23%20%12%
5902
Night
16%7%21%28%21%3
16135

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
18%6%24423345%44%
1746
16th to endDay
18%5%13413336%48%
1885
February1st to 15thDay
17%5%14424446%45%
1870
16th to endDay
17%5%24413437%44%
1580
March1st to 15thDay
17%42433335%6%44%
1913
16th to endDay
16%5%24424446%44%
2111
April1st to 15thDay
12%325%5%25%45%6%45%
2035
16th to endDay
12%32443435%6%48%
2283
May1st to 15thDay
12%435%435%45%7%43%
2331
16th to endDay
11%325%6%45%5%5%8%38%
2431
June1st to 15thDay
9%425%7%5%6%5%8%11%32%
2340
16th to endDay
5%3145%47%7%8%10%40%
2340
July1st to 15thDay
11%435%6%47%8%7%11%28%
2340
16th to endDay
8%426%7%5%8%8%7%10%30%
2465
August1st to 15thDay
11%5%145%48%7%7%11%31%
2340
16th to endDay
14%5%35%7%5%7%6%6%8%28%
2290
September1st to 15thDay
13%5%26%5%35%46%8%37%
1980
16th to endDay
16%5%2443445%5%44%
1980
October1st to 15thDay
15%41222234455%
1950
16th to endDay
12%42321223461%
1920
November1st to 15thDay
13%423223346%54%
1748
16th to endDay
16%413323345%49%
1755
December1st to 15thDay
20%7%2441235%5%42%
1755
16th to endDay
25%7%25%323335%37%
1872
January1st to 15thNight
18%5%34313335%47%
2522
16th to endNight
17%6%24323345%46%
2688
February1st to 15thNight
15%414424336%48%
2248
16th to endNight
16%423423446%46%
1893
March1st to 15thNight
15%424325%446%47%
2046
16th to endNight
13%5%24323436%48%
2112
April1st to 15thNight
13%32321335%7%52%
1923
16th to endNight
10%424434446%50%
1675
May1st to 15thNight
12%424425%5%5%8%43%
1619
16th to endNight
9%415%4246%5%8%45%
1682
June1st to 15thNight
8%4245%35%5%8%11%39%
1620
16th to endNight
6%315%435%6%5%14%43%
1620
July1st to 15thNight
7%5%26%6%35%6%7%11%35%
1620
16th to endNight
7%3245%47%7%8%13%35%
1703
August1st to 15thNight
12%415%5%35%5%8%11%36%
1620
16th to endNight
11%5%26%5%35%6%7%12%34%
1896
September1st to 15thNight
12%5%25%5%35%5%7%9%38%
1980
16th to endNight
14%41442435%7%45%
1980
October1st to 15thNight
14%413212335%55%
2010
16th to endNight
11%31232334360%
2304
November1st to 15thNight
13%313322336%56%
2438
16th to endNight
15%312314346%51%
2535
December1st to 15thNight
18%5%25%423335%45%
2535
16th to endNight
22%6%26%423346%37%
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
42%48%16%23%4
1747
16th to endDay
39%36%20%22%8%
1885
February1st to 15thDay
40%38%19%23%3
1872
16th to endDay
41%46%21%18%7%
1580
March1st to 15thDay
39%5%8%17%21%7%
1913
16th to endDay
41%411%21%17%3
2112
April1st to 15thDay
38%5%9%20%20%5%
2035
16th to endDay
36%5%8%21%22%6%
2283
May1st to 15thDay
39%6%11%19%18%3
2331
16th to endDay
40%8%12%20%14%2
2435
June1st to 15thDay
42%10%18%19%7%2
2340
16th to endDay
34%10%16%20%15%2
2340
July1st to 15thDay
43%11%18%17%6%1
2201
16th to endDay
42%13%17%17%7%1
2310
August1st to 15thDay
44%10%15%19%9%1
2327
16th to endDay
50%9%13%15%9%1
2290
September1st to 15thDay
42%9%11%16%15%3
1980
16th to endDay
40%5%11%18%19%4
1980
October1st to 15thDay
32%5%8%18%27%8%
1950
16th to endDay
28%25%19%30%13%
1920
November1st to 15thDay
32%37%15%30%10%
1748
16th to endDay
36%35%16%29%8%
1755
December1st to 15thDay
43%37%18%17%8%
1755
16th to endDay
50%27%18%14%5%
1872
January1st to 15thNight
41%36%17%24%6%
2522
16th to endNight
40%35%18%23%8%
2688
February1st to 15thNight
37%36%20%23%7%
2257
16th to endNight
37%46%21%23%5%
1893
March1st to 15thNight
37%5%8%18%20%8%
2046
16th to endNight
36%411%22%20%4
2112
April1st to 15thNight
31%410%24%22%6%
1923
16th to endNight
34%6%9%21%20%8%
1675
May1st to 15thNight
37%7%13%20%18%2
1620
16th to endNight
34%8%14%27%12%3
1684
June1st to 15thNight
34%11%18%23%9%1
1620
16th to endNight
31%9%17%25%13%2
1620
July1st to 15thNight
39%11%21%19%7%1
1530
16th to endNight
34%13%19%20%8%2
1595
August1st to 15thNight
38%11%18%20%10%1
1609
16th to endNight
40%11%17%18%11%1
1896
September1st to 15thNight
38%10%15%16%15%3
1980
16th to endNight
37%6%12%21%17%5%
1980
October1st to 15thNight
32%410%18%25%7%
2010
16th to endNight
28%3419%30%13%
2304
November1st to 15thNight
30%36%18%28%12%
2438
16th to endNight
33%46%19%25%9%
2535
December1st to 15thNight
42%38%18%18%7%
2535
16th to endNight
48%48%16%17%5%
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
24%15%31%24%4
135
16th to endDay
18%25%34%18%31
144
February1st to 15thDay
21%20%42%15%
126
16th to endDay
27%9%46%13%2
81
March1st to 15thDay
21%13%29%24%9%1
203
16th to endDay
20%10%27%25%13%1
288
April1st to 15thDay
18%9%27%22%19%2
270
16th to endDay
16%324%28%18%7%
270
May1st to 15thDay
15%7%28%17%14%15%
288
16th to endDay
16%5%17%22%21%16%
331
June1st to 15thDay
12%211%26%26%22%
315
16th to endDay
10%16%25%22%23%
315
July1st to 15thDay
9%29%25%26%25%
305
16th to endDay
9%6%18%36%28%
326
August1st to 15thDay
18%19%23%23%23%
313
16th to endDay
18%17%22%29%19%
332
September1st to 15thDay
14%311%23%28%18%
315
16th to endDay
21%110%25%28%12%
314
October1st to 15thDay
20%216%30%21%7%
315
16th to endDay
14%8%19%25%25%6%
336
November1st to 15thDay
27%6%20%20%21%3
166
16th to endDay
11%8%27%32%15%4
135
December1st to 15thDay
31%9%31%21%6%
135
16th to endDay
35%15%29%17%1
144
January1st to 15thNight
23%15%27%25%7%
780
16th to endNight
22%14%33%26%3
832
February1st to 15thNight
20%14%29%31%4
753
16th to endNight
18%16%35%25%4
631
March1st to 15thNight
19%13%31%28%5%
720
16th to endNight
18%11%26%29%13%
768
April1st to 15thNight
15%12%27%29%13%1
665
16th to endNight
12%6%26%30%21%1
540
May1st to 15thNight
15%5%25%28%23%2
540
16th to endNight
12%116%29%34%4
563
June1st to 15thNight
11%211%31%32%10%
540
16th to endNight
6%12%33%36%10%
540
July1st to 15thNight
10%18%23%44%11%
510
16th to endNight
7%17%27%44%12%
564
August1st to 15thNight
15%8%24%38%12%
539
16th to endNight
13%17%24%42%11%
573
September1st to 15thNight
14%111%25%37%8%
720
16th to endNight
16%114%35%28%3
717
October1st to 15thNight
16%5%18%28%25%5%
720
16th to endNight
13%6%23%30%23%2
768
November1st to 15thNight
15%5%22%32%21%2
760
16th to endNight
17%10%26%29%15%1
780
December1st to 15thNight
20%11%25%29%11%
780
16th to endNight
26%10%26%28%6%
832
Page generated at 2018-02-13 20:46:09. Version ac04

Copyright 2018 A. Danko


Dogshead Clear Sky Chart |Charts Home