Dogwood Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dogwood Observatory clear sky chart from 2005-11-06 to 2024-01-15.

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
28%
23143
19%
74662
8%
23101
41%
23101
20%
47963

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 10thNight
16%
760
22%
2649
7%
757
35%
757
16%
1626
January11th to 20thNight
19%
737
19%
2577
6%
737
36%
737
15%
1684
January21st to endNight
14%
792
23%
2595
5%
792
35%
792
18%
1597
February1st to 10thNight
13%
720
17%
2340
4%
720
29%
720
15%
1550
February11th to 20thNight
11%
703
20%
2122
3%
700
32%
700
13%
1410
February21st to endNight
14%
592
25%
1776
7%
592
36%
592
16%
1157
March1st to 10thNight
17%
720
21%
2160
7%
720
35%
720
19%
1359
March11th to 20thNight
18%
720
22%
2021
6%
720
33%
720
18%
1369
March21st to endNight
17%
792
22%
2026
5%
792
29%
792
22%
1394
April1st to 10thNight
18%
720
18%
1800
3%
720
27%
720
19%
1259
April11th to 20thNight
21%
711
18%
1775
4%
711
29%
711
23%
1222
April21st to endNight
23%
720
19%
1800
4%
720
31%
720
24%
1247
May1st to 10thNight
21%
550
15%
1630
6%
550
28%
550
16%
1161
May11th to 20thNight
25%
354
19%
1416
10%
354
40%
354
16%
901
May21st to endNight
44%
388
15%
1551
13%
388
52%
388
19%
976
June1st to 10thNight
39%
360
18%
1440
14%
360
52%
360
21%
862
June11th to 20thNight
40%
360
15%
1440
12%
360
51%
360
19%
891
June21st to endNight
50%
360
16%
1440
15%
360
59%
360
24%
842
July1st to 10thNight
50%
350
14%
1400
15%
350
56%
350
19%
868
July11th to 20thNight
52%
348
15%
1392
16%
348
57%
348
21%
856
July21st to endNight
51%
394
18%
1486
17%
372
59%
372
25%
843
August1st to 10thNight
53%
499
16%
1563
11%
497
57%
497
26%
1001
August11th to 20thNight
50%
701
15%
1765
8%
701
52%
701
26%
1263
August21st to endNight
49%
792
18%
1980
8%
792
52%
792
29%
1347
September1st to 10thNight
42%
720
20%
1800
9%
720
48%
720
28%
1240
September11th to 20thNight
47%
720
27%
1852
16%
720
53%
720
35%
1151
September21st to endNight
40%
720
25%
1980
15%
720
50%
720
28%
1288
October1st to 10thNight
35%
720
16%
2117
10%
720
42%
720
23%
1401
October11th to 20thNight
34%
720
23%
2160
12%
720
47%
720
26%
1329
October21st to endNight
26%
792
22%
2485
11%
792
41%
792
21%
1612
November1st to 10thNight
31%
740
25%
2407
11%
740
49%
740
26%
1399
November11th to 20thNight
26%
760
26%
2470
11%
760
44%
760
21%
1526
November21st to endNight
24%
760
22%
2579
8%
760
42%
760
20%
1557
December1st to 10thNight
20%
760
19%
2660
7%
760
35%
760
15%
1737
December11th to 20thNight
18%
760
19%
3197
5%
759
36%
759
14%
1953
December21st to endNight
16%
828
13%
4811
5%
817
34%
817
9%
3085

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
16%6%35%5%35%5%5%7%40%
74766
Night
17%7%35%43445%7%42%
74997
TransparencyDay
43%6%11%21%15%2
74471
Night
42%6%12%22%16%3
74826
SeeingDay
23%16%30%19%9%2
13835
Night
21%14%31%24%8%1
23152

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 10thDay
13%7%35%6%35%5%5%6%41%
1517
11th to 20thDay
16%7%37%6%36%46%6%35%
1472
21st to endDay
14%7%36%435%5%5%7%41%
1760
February1st to 10thDay
17%9%36%5%3345%7%37%
1620
11th to 20thDay
16%7%36%6%34446%41%
1725
21st to endDay
21%9%35%5%34445%37%
1480
March1st to 10thDay
15%7%36%5%24347%44%
1797
11th to 20thDay
15%7%35%6%35%46%7%38%
1934
21st to endDay
21%7%25%433446%40%
2330
April1st to 10thDay
18%7%36%434446%40%
2160
11th to 20thDay
17%5%35%435%46%7%40%
2134
21st to endDay
19%6%35%5%35%45%6%39%
2160
May1st to 10thDay
22%7%36%5%345%5%6%34%
2345
11th to 20thDay
21%5%25%445%5%5%7%37%
2478
21st to endDay
16%7%25%6%245%5%8%41%
2725
June1st to 10thDay
16%6%345%35%6%6%9%37%
2520
11th to 20thDay
16%6%26%6%46%6%5%8%35%
2520
21st to endDay
14%5%25%5%35%5%6%8%40%
2520
July1st to 10thDay
12%6%36%7%46%5%6%9%37%
2520
11th to 20thDay
10%5%25%5%35%6%7%11%41%
2520
21st to endDay
13%6%36%6%46%5%7%8%37%
2744
August1st to 10thDay
11%5%25%6%47%7%7%9%36%
2353
11th to 20thDay
13%6%26%5%45%6%6%8%39%
2126
21st to endDay
16%6%25%6%4445%8%41%
2376
September1st to 10thDay
16%5%25%5%35%5%5%7%43%
2160
11th to 20thDay
14%5%2343445%8%49%
2106
21st to endDay
17%6%26%6%35%446%41%
1980
October1st to 10thDay
21%5%2443445%8%40%
1840
11th to 20thDay
17%5%245%35%447%45%
1800
21st to endDay
21%6%24434446%42%
1869
November1st to 10thDay
14%6%34423346%52%
1671
11th to 20thDay
19%5%244235%5%6%46%
1710
21st to endDay
15%6%345%3445%7%44%
1596
December1st to 10thDay
20%7%25%5%2445%8%37%
1520
11th to 20thDay
21%5%25%3245%5%6%41%
1906
21st to endDay
18%9%36%6%46%5%6%7%30%
2772
January1st to 10thNight
15%7%25%43345%7%44%
2649
11th to 20thNight
19%7%25%5%3445%7%39%
2577
21st to endNight
14%8%35%424447%44%
2595
February1st to 10thNight
17%9%35%5%34446%40%
2340
11th to 20thNight
17%7%45%5%3445%5%41%
2120
21st to endNight
20%7%345%24346%42%
1776
March1st to 10thNight
16%6%2443345%8%44%
2150
11th to 20thNight
18%7%345%245%45%42%
2020
21st to endNight
17%7%35%424446%42%
2026
April1st to 10thNight
17%7%346%35%5%5%7%38%
1800
11th to 20thNight
17%7%245%35%447%41%
1775
21st to endNight
20%6%3432446%6%42%
1800
May1st to 10thNight
20%9%47%434435%36%
1630
11th to 20thNight
18%7%35%435%5%45%40%
1415
21st to endNight
17%5%35%44446%8%41%
1550
June1st to 10thNight
17%43443445%8%43%
1440
11th to 20thNight
14%6%36%43447%9%40%
1440
21st to endNight
12%4245%35%5%6%10%45%
1440
July1st to 10thNight
13%5%25%6%45%5%6%10%40%
1440
11th to 20thNight
11%425%6%36%6%7%9%40%
1440
21st to endNight
11%5%25%4346%7%10%43%
1574
August1st to 10thNight
10%6%26%5%45%6%6%10%41%
1573
11th to 20thNight
12%6%36%6%46%6%5%8%37%
1765
21st to endNight
14%6%25%6%345%5%8%42%
1980
September1st to 10thNight
17%6%25%5%345%5%6%43%
1800
11th to 20thNight
15%5%24423347%51%
1852
21st to endNight
18%6%25%42335%6%46%
1980
October1st to 10thNight
20%7%35%424446%43%
2117
11th to 20thNight
16%5%24433446%49%
2160
21st to endNight
22%6%24333346%44%
2485
November1st to 10thNight
13%6%15%42335%6%51%
2407
11th to 20thNight
20%6%24323435%48%
2470
21st to endNight
14%6%344245%5%7%45%
2579
December1st to 10thNight
20%7%35%435%45%7%38%
2660
11th to 20thNight
19%7%25%43445%7%41%
3288
21st to endNight
20%9%36%5%34445%37%
4884

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 10thDay
43%5%12%24%13%4
1518
11th to 20thDay
49%6%13%18%11%3
1472
21st to endDay
43%5%10%25%14%3
1760
February1st to 10thDay
48%5%13%21%11%2
1620
11th to 20thDay
45%5%9%23%14%3
1734
21st to endDay
50%39%21%13%4
1480
March1st to 10thDay
41%5%12%25%14%3
1800
11th to 20thDay
44%6%11%20%16%2
1934
21st to endDay
47%49%17%17%5%
2330
April1st to 10thDay
45%5%9%20%16%5%
2160
11th to 20thDay
43%5%12%20%17%4
2134
21st to endDay
45%5%9%19%16%5%
2160
May1st to 10thDay
50%5%8%17%17%3
2345
11th to 20thDay
46%7%10%20%15%3
2482
21st to endDay
42%7%14%21%14%2
2725
June1st to 10thDay
43%8%14%19%15%1
2520
11th to 20thDay
46%9%11%21%11%2
2520
21st to endDay
40%9%12%23%15%1
2520
July1st to 10thDay
43%9%11%21%15%2
2450
11th to 20thDay
35%9%15%23%15%2
2445
21st to endDay
42%8%12%19%17%3
2591
August1st to 10thDay
40%11%13%20%15%1
2339
11th to 20thDay
41%8%14%22%13%1
2126
21st to endDay
41%7%10%21%18%3
2376
September1st to 10thDay
40%8%10%21%18%3
2160
11th to 20thDay
35%5%11%22%25%3
2106
21st to endDay
45%6%9%18%20%3
1980
October1st to 10thDay
43%7%11%20%16%2
1840
11th to 20thDay
39%5%11%24%19%1
1800
21st to endDay
44%410%22%17%2
1869
November1st to 10thDay
35%5%12%24%21%3
1671
11th to 20thDay
39%411%22%21%3
1710
21st to endDay
40%413%29%12%2
1596
December1st to 10thDay
47%5%14%19%13%1
1520
11th to 20thDay
43%6%15%23%11%1
1906
21st to endDay
52%7%12%20%8%
2772
January1st to 10thNight
41%5%11%25%15%4
2649
11th to 20thNight
45%6%14%22%10%2
2577
21st to endNight
41%410%23%19%3
2595
February1st to 10thNight
45%6%12%23%11%2
2340
11th to 20thNight
45%5%11%18%17%5%
2122
21st to endNight
44%38%24%17%3
1776
March1st to 10thNight
40%5%13%24%15%4
2160
11th to 20thNight
44%6%9%20%18%3
2021
21st to endNight
43%5%10%17%19%5%
2026
April1st to 10thNight
45%6%11%20%15%4
1800
11th to 20thNight
43%5%9%20%20%2
1775
21st to endNight
43%6%10%21%17%4
1800
May1st to 10thNight
50%6%10%17%16%2
1630
11th to 20thNight
45%7%11%16%18%3
1416
21st to endNight
40%9%13%21%13%3
1551
June1st to 10thNight
41%5%12%22%18%2
1440
11th to 20thNight
40%9%14%24%12%1
1440
21st to endNight
33%11%15%24%16%1
1440
July1st to 10thNight
39%11%14%20%15%2
1400
11th to 20thNight
37%11%12%26%12%2
1392
21st to endNight
33%9%17%22%17%3
1486
August1st to 10thNight
36%10%15%22%15%1
1563
11th to 20thNight
43%10%14%20%12%1
1765
21st to endNight
39%8%12%19%20%2
1980
September1st to 10thNight
42%7%10%22%18%1
1800
11th to 20thNight
34%5%10%22%25%4
1852
21st to endNight
40%5%7%24%23%2
1980
October1st to 10thNight
44%5%11%23%14%2
2117
11th to 20thNight
38%5%13%27%16%2
2160
21st to endNight
43%5%10%25%16%1
2485
November1st to 10thNight
34%5%11%23%22%4
2407
11th to 20thNight
40%49%23%19%4
2470
21st to endNight
38%5%13%27%15%2
2579
December1st to 10thNight
45%7%12%23%13%1
2660
11th to 20thNight
43%5%13%19%16%3
3288
21st to endNight
50%5%12%22%11%
4884

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 10thDay
28%24%34%11%21
180
11th to 20thDay
36%23%30%10%1
168
21st to endDay
26%30%31%7%5%
254
February1st to 10thDay
34%31%28%6%2
240
11th to 20thDay
30%25%34%10%1
393
21st to endDay
35%23%27%12%2
346
March1st to 10thDay
29%23%31%14%3
420
11th to 20thDay
26%27%30%13%31
420
21st to endDay
32%21%30%12%41
462
April1st to 10thDay
30%22%30%11%7%
420
11th to 20thDay
25%22%30%14%8%1
412
21st to endDay
32%19%34%11%21
420
May1st to 10thDay
32%19%29%12%6%1
423
11th to 20thDay
23%16%36%17%6%1
447
21st to endDay
22%9%27%29%12%2
485
June1st to 10thDay
18%16%31%22%12%1
450
11th to 20thDay
21%14%32%23%9%2
450
21st to endDay
17%10%33%26%11%1
450
July1st to 10thDay
14%8%28%28%18%5%
445
11th to 20thDay
12%327%37%18%3
444
21st to endDay
17%9%31%27%13%3
488
August1st to 10thDay
13%7%26%31%17%5%
446
11th to 20thDay
16%5%26%33%15%5%
439
21st to endDay
14%8%32%26%13%6%
495
September1st to 10thDay
20%12%25%24%15%5%
450
11th to 20thDay
17%9%31%21%13%9%
450
21st to endDay
21%15%29%21%9%5%
450
October1st to 10thDay
27%7%30%19%12%4
450
11th to 20thDay
18%18%31%22%9%1
450
21st to endDay
27%16%33%17%7%1
439
November1st to 10thDay
21%15%29%22%10%3
365
11th to 20thDay
28%18%32%18%5%
370
21st to endDay
22%21%37%16%4
256
December1st to 10thDay
31%26%27%11%6%
180
11th to 20thDay
34%26%26%10%3
180
21st to endDay
30%20%32%13%41
198
January1st to 10thNight
23%22%36%16%3
760
11th to 20thNight
27%17%33%19%3
737
21st to endNight
21%21%38%17%2
792
February1st to 10thNight
25%20%36%17%2
720
11th to 20thNight
25%25%35%13%1
703
21st to endNight
28%20%35%14%2
592
March1st to 10thNight
24%23%32%18%3
720
11th to 20thNight
24%21%33%18%31
720
21st to endNight
22%20%38%14%5%1
792
April1st to 10thNight
23%22%33%17%4
720
11th to 20thNight
22%18%36%19%5%
711
21st to endNight
24%15%35%22%4
720
May1st to 10thNight
26%17%31%20%6%
550
11th to 20thNight
23%12%35%23%6%
354
21st to endNight
19%7%25%36%12%1
389
June1st to 10thNight
19%7%29%33%11%1
360
11th to 20thNight
14%7%32%35%12%
360
21st to endNight
12%428%45%11%
360
July1st to 10thNight
14%6%26%34%19%2
350
11th to 20thNight
11%425%41%18%1
348
21st to endNight
15%325%42%14%1
394
August1st to 10thNight
12%223%40%19%2
499
11th to 20thNight
14%322%37%22%2
701
21st to endNight
16%423%35%20%2
792
September1st to 10thNight
19%426%33%15%2
720
11th to 20thNight
18%426%30%19%3
720
21st to endNight
20%6%28%30%13%2
720
October1st to 10thNight
23%9%27%25%13%2
720
11th to 20thNight
19%14%29%28%10%
720
21st to endNight
25%15%31%22%7%
792
November1st to 10thNight
17%14%32%26%9%1
740
11th to 20thNight
25%15%30%23%6%
760
21st to endNight
19%19%35%21%6%1
760
December1st to 10thNight
25%18%32%20%41
760
11th to 20thNight
23%19%35%20%3
760
21st to endNight
25%17%36%20%2
836
Page generated at 2024-01-11 22:33:50. Version ac07

Copyright 2024 Attilla Danko


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