The Hughesville Sky-view Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The Hughesville Sky-view Observatory clear sky chart from 2005-11-06 to 2024-01-16.

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
34%
23524
21%
74680
10%
23476
46%
23476
23%
46287

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%
758
24%
2611
7%
757
38%
757
18%
1551
January11th to 20thNight
22%
744
22%
2417
8%
744
40%
744
17%
1566
January21st to endNight
18%
792
26%
2574
8%
792
39%
792
20%
1549
February1st to 10thNight
20%
720
19%
2340
7%
720
36%
720
19%
1480
February11th to 20thNight
11%
701
20%
2191
4%
700
32%
700
16%
1401
February21st to endNight
15%
592
25%
1776
6%
592
37%
592
19%
1131
March1st to 10thNight
20%
720
25%
2036
8%
720
39%
720
23%
1255
March11th to 20thNight
19%
720
21%
1980
7%
720
34%
720
22%
1306
March21st to endNight
18%
792
21%
2127
6%
792
31%
792
22%
1417
April1st to 10thNight
20%
720
20%
1800
3%
720
31%
720
23%
1201
April11th to 20thNight
30%
711
22%
1775
6%
711
38%
711
31%
1139
April21st to endNight
29%
720
21%
1800
7%
720
35%
720
27%
1202
May1st to 10thNight
29%
644
18%
1724
7%
644
36%
644
25%
1160
May11th to 20thNight
36%
407
17%
1468
10%
407
45%
407
21%
921
May21st to endNight
50%
388
17%
1551
16%
388
57%
388
22%
922
June1st to 10thNight
51%
360
19%
1440
17%
360
60%
360
24%
834
June11th to 20thNight
51%
360
17%
1440
16%
360
58%
360
22%
850
June21st to endNight
51%
360
17%
1440
16%
360
58%
360
25%
810
July1st to 10thNight
56%
350
15%
1400
16%
350
62%
350
23%
831
July11th to 20thNight
65%
406
17%
1450
17%
406
66%
406
28%
812
July21st to endNight
58%
591
18%
1672
12%
558
63%
558
31%
1029
August1st to 10thNight
63%
537
16%
1600
11%
534
65%
534
29%
1022
August11th to 20thNight
55%
641
16%
1705
9%
641
57%
641
26%
1183
August21st to endNight
56%
792
19%
1980
10%
792
58%
792
32%
1319
September1st to 10thNight
55%
720
22%
1800
12%
720
59%
720
34%
1186
September11th to 20thNight
60%
720
29%
1800
18%
720
65%
720
38%
1123
September21st to endNight
40%
720
20%
2047
12%
720
48%
720
24%
1376
October1st to 10thNight
46%
720
20%
2160
17%
720
53%
720
27%
1365
October11th to 20thNight
38%
720
27%
2160
17%
720
52%
720
27%
1300
October21st to endNight
32%
792
28%
2376
15%
792
48%
792
27%
1430
November1st to 10thNight
35%
740
26%
2332
14%
740
51%
740
29%
1353
November11th to 20thNight
28%
760
26%
2470
13%
760
45%
760
24%
1456
November21st to endNight
32%
760
25%
2629
13%
760
49%
760
24%
1449
December1st to 10thNight
23%
760
21%
2660
7%
760
42%
760
18%
1638
December11th to 20thNight
22%
760
22%
3163
9%
759
39%
759
17%
1866
December21st to endNight
25%
826
15%
4786
10%
817
42%
817
11%
2854

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
13%6%25%5%35%5%6%8%43%
74719
Night
14%6%35%5%3445%7%44%
75095
TransparencyDay
38%6%12%24%16%3
74429
Night
39%6%12%23%17%4
74904
SeeingDay
18%15%29%23%11%4
13925
Night
18%14%29%27%11%1
23539

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 10thDay
15%7%25%5%345%6%5%43%
1554
11th to 20thDay
16%8%36%43345%6%42%
1671
21st to endDay
15%6%37%6%34446%43%
1782
February1st to 10thDay
15%8%35%5%45%6%5%6%38%
1620
11th to 20thDay
18%6%345%25%45%6%43%
1654
21st to endDay
17%10%36%5%44346%38%
1480
March1st to 10thDay
13%6%25%424347%50%
1921
11th to 20thDay
18%6%25%5%34446%43%
1980
21st to endDay
17%7%36%6%3445%6%40%
2227
April1st to 10thDay
12%6%246%3445%8%45%
2160
11th to 20thDay
12%6%25%43445%7%49%
2134
21st to endDay
17%6%25%4345%47%42%
2160
May1st to 10thDay
15%6%25%435%5%6%10%39%
2250
11th to 20thDay
17%5%25%5%35%5%5%9%38%
2424
21st to endDay
13%5%25%5%35%6%6%9%41%
2725
June1st to 10thDay
11%425%6%45%5%6%11%42%
2520
11th to 20thDay
11%5%245%46%6%7%9%42%
2520
21st to endDay
9%3246%36%6%8%11%42%
2520
July1st to 10thDay
8%6%36%445%6%6%10%41%
2520
11th to 20thDay
5%3246%45%6%7%13%45%
2458
21st to endDay
9%5%26%5%47%7%8%10%36%
2547
August1st to 10thDay
9%6%36%6%47%7%7%10%35%
2327
11th to 20thDay
10%5%36%6%35%6%7%10%38%
2177
21st to endDay
9%6%25%6%35%6%6%9%42%
2376
September1st to 10thDay
14%425%5%35%5%5%9%45%
2160
11th to 20thDay
11%5%345%3446%9%46%
2160
21st to endDay
17%9%345%345%5%7%39%
1908
October1st to 10thDay
16%5%2443445%7%46%
1800
11th to 20thDay
17%424333436%51%
1800
21st to endDay
13%6%26%43445%6%47%
1980
November1st to 10thDay
12%4145%23447%53%
1743
11th to 20thDay
14%5%2332345%6%51%
1710
21st to endDay
14%5%25%433446%50%
1549
December1st to 10thDay
16%6%244445%5%8%41%
1520
11th to 20thDay
16%7%25%424445%48%
1910
21st to endDay
16%8%26%5%345%6%6%38%
2772
January1st to 10thNight
15%7%35%424446%47%
2611
11th to 20thNight
16%7%45%5%345%5%5%40%
2417
21st to endNight
15%7%35%423446%48%
2574
February1st to 10thNight
16%7%25%435%5%47%42%
2340
11th to 20thNight
18%8%35%434346%44%
2189
21st to endNight
18%8%34324347%44%
1776
March1st to 10thNight
13%5%345%2345%6%49%
2036
11th to 20thNight
18%6%2444445%7%43%
1980
21st to endNight
15%7%36%5%3445%7%43%
2127
April1st to 10thNight
15%7%25%5%2445%7%43%
1800
11th to 20thNight
13%5%25%5%2445%7%49%
1775
21st to endNight
19%5%2442445%8%42%
1800
May1st to 10thNight
15%7%36%435%5%6%7%40%
1724
11th to 20thNight
15%6%26%5%345%6%10%38%
1468
21st to endNight
13%5%25%435%5%6%10%41%
1550
June1st to 10thNight
11%5%345%246%7%11%42%
1440
11th to 20thNight
11%5%36%5%35%5%6%10%40%
1440
21st to endNight
9%435%436%6%8%11%42%
1440
July1st to 10thNight
8%436%6%45%5%7%12%41%
1440
11th to 20thNight
5%435%5%5%5%6%6%11%45%
1498
21st to endNight
7%425%7%46%5%8%11%40%
1771
August1st to 10thNight
8%5%36%5%37%7%7%9%41%
1611
11th to 20thNight
10%5%37%6%45%7%7%8%37%
1705
21st to endNight
10%6%36%6%35%46%9%42%
1980
September1st to 10thNight
13%6%345%3445%9%45%
1800
11th to 20thNight
9%5%25%5%3446%8%49%
1800
21st to endNight
18%8%25%43346%7%39%
2047
October1st to 10thNight
16%6%25%5%335%46%45%
2160
11th to 20thNight
15%5%26%423346%50%
2160
21st to endNight
15%5%24434447%48%
2376
November1st to 10thNight
12%6%24433345%53%
2332
11th to 20thNight
15%6%34333346%49%
2470
21st to endNight
12%5%234345%5%7%50%
2629
December1st to 10thNight
17%7%35%43445%6%42%
2660
11th to 20thNight
17%5%25%43445%7%44%
3285
21st to endNight
15%8%25%5%45%5%6%8%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
41%6%9%25%15%4
1555
11th to 20thDay
42%412%23%16%3
1671
21st to endDay
42%49%24%17%4
1782
February1st to 10thDay
45%6%11%25%11%2
1620
11th to 20thDay
42%5%8%24%17%4
1663
21st to endDay
48%411%17%16%4
1480
March1st to 10thDay
36%410%25%21%3
1921
11th to 20thDay
42%5%9%20%18%6%
1980
21st to endDay
45%5%9%19%17%4
2227
April1st to 10thDay
37%6%11%22%19%6%
2160
11th to 20thDay
35%5%10%22%21%7%
2134
21st to endDay
41%6%10%22%16%5%
2160
May1st to 10thDay
39%7%14%20%16%3
2250
11th to 20thDay
42%7%13%22%14%2
2428
21st to endDay
38%7%14%27%12%2
2725
June1st to 10thDay
35%7%14%27%15%1
2520
11th to 20thDay
35%9%14%22%17%2
2520
21st to endDay
34%8%15%25%16%2
2520
July1st to 10thDay
37%9%13%22%16%3
2450
11th to 20thDay
29%9%18%27%15%3
2383
21st to endDay
37%10%14%21%17%1
2405
August1st to 10thDay
40%9%14%25%11%
2314
11th to 20thDay
39%8%16%22%14%1
2177
21st to endDay
36%8%14%24%14%4
2376
September1st to 10thDay
38%6%13%21%18%4
2160
11th to 20thDay
34%6%10%26%20%4
2160
21st to endDay
45%6%8%21%17%3
1908
October1st to 10thDay
38%6%9%25%19%3
1800
11th to 20thDay
36%48%26%22%4
1800
21st to endDay
37%5%7%26%21%4
1980
November1st to 10thDay
32%411%28%21%5%
1743
11th to 20thDay
34%411%23%22%5%
1710
21st to endDay
36%310%28%20%3
1549
December1st to 10thDay
41%6%13%25%12%4
1520
11th to 20thDay
38%49%31%14%3
1906
21st to endDay
43%7%12%26%12%1
2772
January1st to 10thNight
39%49%23%19%6%
2611
11th to 20thNight
45%411%22%16%2
2417
21st to endNight
39%38%26%21%2
2574
February1st to 10thNight
42%411%25%16%2
2340
11th to 20thNight
43%48%21%18%6%
2191
21st to endNight
42%410%22%16%5%
1776
March1st to 10thNight
37%49%27%20%3
2036
11th to 20thNight
41%6%10%22%18%3
1980
21st to endNight
42%5%10%20%17%6%
2127
April1st to 10thNight
41%5%10%20%20%5%
1800
11th to 20thNight
35%5%11%21%21%6%
1775
21st to endNight
40%6%11%25%13%5%
1800
May1st to 10thNight
41%7%12%22%14%4
1724
11th to 20thNight
41%7%15%18%17%2
1469
21st to endNight
37%8%17%23%13%1
1551
June1st to 10thNight
34%9%13%25%17%2
1440
11th to 20thNight
38%7%15%24%13%3
1440
21st to endNight
34%7%18%19%19%3
1440
July1st to 10thNight
37%9%19%19%13%4
1400
11th to 20thNight
31%9%18%25%15%2
1450
21st to endNight
34%9%16%27%14%
1672
August1st to 10thNight
36%9%18%22%14%1
1600
11th to 20thNight
42%9%15%21%12%1
1705
21st to endNight
38%7%15%23%15%3
1980
September1st to 10thNight
38%5%13%22%17%6%
1800
11th to 20thNight
32%6%11%25%22%3
1800
21st to endNight
44%6%10%20%17%3
2047
October1st to 10thNight
40%5%10%24%18%4
2160
11th to 20thNight
37%48%27%21%3
2160
21st to endNight
36%48%26%22%4
2376
November1st to 10thNight
35%49%26%21%6%
2332
11th to 20thNight
38%39%21%22%6%
2470
21st to endNight
33%411%26%22%4
2629
December1st to 10thNight
42%411%25%15%3
2660
11th to 20thNight
40%49%23%19%4
3288
21st to endNight
42%8%14%23%11%1
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
25%30%29%11%41
198
11th to 20thDay
26%30%30%12%2
257
21st to endDay
22%36%31%9%2
264
February1st to 10thDay
23%30%33%10%3
240
11th to 20thDay
30%26%35%8%1
321
21st to endDay
30%27%31%11%2
346
March1st to 10thDay
20%30%33%15%1
420
11th to 20thDay
26%24%31%14%31
420
21st to endDay
22%23%35%15%41
462
April1st to 10thDay
20%25%36%14%5%
420
11th to 20thDay
18%19%35%18%8%2
412
21st to endDay
23%20%34%16%5%1
420
May1st to 10thDay
24%19%30%17%8%1
423
11th to 20thDay
22%15%32%23%6%2
447
21st to endDay
20%7%26%28%14%4
485
June1st to 10thDay
12%11%30%28%16%3
450
11th to 20thDay
14%8%34%27%14%4
450
21st to endDay
12%8%31%32%13%4
450
July1st to 10thDay
12%424%33%20%8%
445
11th to 20thDay
4320%44%22%8%
444
21st to endDay
11%325%34%19%7%
488
August1st to 10thDay
11%7%21%34%20%7%
446
11th to 20thDay
12%419%36%21%8%
439
21st to endDay
11%5%23%32%18%12%
495
September1st to 10thDay
16%6%21%27%16%14%
450
11th to 20thDay
13%6%27%30%13%11%
450
21st to endDay
26%11%27%23%10%4
450
October1st to 10thDay
20%10%26%24%16%4
450
11th to 20thDay
18%16%28%25%12%2
450
21st to endDay
17%16%38%18%8%2
495
November1st to 10thDay
17%15%34%20%10%3
401
11th to 20thDay
19%23%29%19%8%1
370
21st to endDay
19%24%31%17%10%
209
December1st to 10thDay
22%25%37%12%41
180
11th to 20thDay
24%27%27%18%4
180
21st to endDay
25%24%28%19%41
198
January1st to 10thNight
22%23%34%17%3
760
11th to 20thNight
22%21%31%22%4
744
21st to endNight
21%22%36%19%2
792
February1st to 10thNight
20%22%35%20%3
720
11th to 20thNight
24%27%34%13%2
703
21st to endNight
25%23%34%16%2
592
March1st to 10thNight
19%23%34%21%3
720
11th to 20thNight
23%19%36%16%6%1
720
21st to endNight
20%19%40%17%4
792
April1st to 10thNight
20%22%35%18%3
720
11th to 20thNight
16%15%36%26%7%
711
21st to endNight
21%14%32%24%8%
720
May1st to 10thNight
19%11%36%24%10%1
644
11th to 20thNight
17%9%33%33%8%
407
21st to endNight
15%6%23%37%17%2
389
June1st to 10thNight
12%426%39%17%1
360
11th to 20thNight
13%5%24%41%15%2
360
21st to endNight
9%5%26%43%14%2
360
July1st to 10thNight
9%421%39%25%2
350
11th to 20thNight
6%215%44%29%4
406
21st to endNight
9%322%38%25%4
591
August1st to 10thNight
9%216%44%26%3
537
11th to 20thNight
12%417%41%24%2
641
21st to endNight
11%418%34%27%5%
792
September1st to 10thNight
17%317%34%24%4
720
11th to 20thNight
11%416%39%25%4
720
21st to endNight
23%5%25%28%18%1
720
October1st to 10thNight
20%7%21%31%17%5%
720
11th to 20thNight
18%13%25%27%15%2
720
21st to endNight
20%14%30%23%12%1
792
November1st to 10thNight
14%13%33%27%11%2
740
11th to 20thNight
19%18%31%24%8%1
760
21st to endNight
16%20%29%25%9%1
760
December1st to 10thNight
24%18%30%18%9%1
760
11th to 20thNight
20%17%37%21%5%
760
21st to endNight
20%18%31%28%4
836
Page generated at 2024-01-13 19:28:30. Version ac07

Copyright 2024 Attilla Danko


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