Pickersville Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pickersville Observatory clear sky chart from 2005-11-06 to 2024-03-08.

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%
24820
21%
80135
14%
24728
54%
24728
26%
49846

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
31%
752
26%
3999
13%
737
46%
737
18%
2112
January11th to 20thNight
33%
755
25%
3972
13%
740
48%
740
15%
2298
January21st to endNight
29%
829
18%
4450
13%
814
47%
814
17%
2592
February1st to 10thNight
33%
760
21%
2470
13%
760
46%
760
26%
1526
February11th to 20thNight
22%
740
19%
2360
9%
739
35%
739
21%
1523
February21st to endNight
28%
628
26%
1746
13%
628
41%
628
28%
1125
March1st to 10thNight
33%
751
25%
2064
15%
751
43%
751
30%
1303
March11th to 20thNight
30%
720
19%
1980
10%
720
39%
720
25%
1341
March21st to endNight
34%
792
21%
2178
10%
792
43%
792
28%
1425
April1st to 10thNight
34%
720
23%
1859
10%
720
42%
720
32%
1181
April11th to 20thNight
41%
711
25%
1775
10%
711
48%
711
36%
1145
April21st to endNight
47%
720
24%
1800
10%
720
53%
720
38%
1136
May1st to 10thNight
45%
630
18%
1710
9%
630
49%
630
32%
1062
May11th to 20thNight
51%
531
17%
1592
10%
531
56%
531
26%
1047
May21st to endNight
67%
582
17%
1744
14%
582
68%
582
29%
1106
June1st to 10thNight
61%
540
15%
1620
12%
540
63%
540
28%
1049
June11th to 20thNight
62%
540
13%
1620
11%
540
64%
540
27%
1071
June21st to endNight
66%
540
15%
1620
13%
540
67%
540
25%
1088
July1st to 10thNight
67%
525
13%
1575
11%
525
68%
525
23%
1089
July11th to 20thNight
70%
522
12%
1566
10%
522
71%
522
27%
1017
July21st to endNight
68%
591
14%
1672
11%
558
68%
558
26%
1118
August1st to 10thNight
64%
537
11%
1600
9%
534
65%
534
22%
1110
August11th to 20thNight
63%
615
13%
1679
10%
615
63%
615
22%
1211
August21st to endNight
66%
792
15%
1980
10%
792
67%
792
27%
1401
September1st to 10thNight
68%
720
22%
1800
17%
720
68%
720
31%
1219
September11th to 20thNight
61%
720
22%
1894
18%
720
63%
720
29%
1269
September21st to endNight
49%
720
17%
2031
14%
720
53%
720
22%
1428
October1st to 10thNight
57%
720
24%
2160
23%
720
62%
720
32%
1313
October11th to 20thNight
52%
720
30%
2160
25%
720
62%
720
35%
1252
October21st to endNight
52%
792
31%
2376
23%
792
64%
792
37%
1332
November1st to 10thNight
49%
740
27%
2221
21%
740
57%
740
34%
1305
November11th to 20thNight
44%
760
27%
2280
19%
760
55%
760
31%
1373
November21st to endNight
45%
760
27%
2507
19%
760
57%
760
32%
1425
December1st to 10thNight
36%
760
20%
2660
13%
760
47%
760
21%
1697
December11th to 20thNight
41%
759
25%
3017
19%
758
51%
758
23%
1773
December21st to endNight
37%
826
17%
4398
15%
817
49%
817
16%
2384

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%5%25%5%35%5%6%8%44%
78642
Night
14%5%35%5%3445%7%45%
80910
TransparencyDay
38%7%12%20%18%5%
78364
Night
38%7%11%19%20%5%
80707
SeeingDay
15%8%23%25%20%10%
14484
Night
15%7%25%34%19%2
24856

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
16%5%24423335%51%
2836
11th to 20thDay
14%5%24423345%53%
2840
21st to endDay
17%8%26%434445%44%
3124
February1st to 10thDay
15%6%25%43445%8%43%
1710
11th to 20thDay
20%5%25%423346%45%
1705
21st to endDay
19%6%35%5%34446%41%
1703
March1st to 10thDay
16%5%24424446%50%
2057
11th to 20thDay
15%5%35%5%35%5%5%8%41%
1980
21st to endDay
14%8%36%6%3445%6%41%
2178
April1st to 10thDay
11%41343345%7%55%
2101
11th to 20thDay
11%4244245%5%8%50%
2134
21st to endDay
12%5%2443446%7%49%
2160
May1st to 10thDay
10%5%35%5%35%46%9%45%
2265
11th to 20thDay
12%6%36%6%35%5%5%6%42%
2301
21st to endDay
10%6%25%6%36%6%7%10%39%
2531
June1st to 10thDay
10%5%36%6%47%6%7%9%37%
2340
11th to 20thDay
9%425%6%36%6%7%11%42%
2340
21st to endDay
8%5%25%6%46%7%7%11%39%
2340
July1st to 10thDay
9%5%26%7%48%7%8%12%33%
2340
11th to 20thDay
9%5%36%6%46%7%9%12%34%
2340
21st to endDay
6%5%37%6%47%7%9%12%36%
2547
August1st to 10thDay
11%5%36%7%5%6%7%8%10%31%
2327
11th to 20thDay
11%6%38%7%5%6%7%8%9%32%
2201
21st to endDay
11%6%35%6%5%6%6%7%10%34%
2376
September1st to 10thDay
8%5%25%6%36%7%7%9%42%
2160
11th to 20thDay
14%6%26%5%35%46%7%42%
2062
21st to endDay
18%7%35%5%35%5%5%7%37%
1927
October1st to 10thDay
16%6%3442345%7%47%
1800
11th to 20thDay
12%5%25%432345%56%
1800
21st to endDay
11%5%245%23245%56%
1980
November1st to 10thDay
13%6%24323346%54%
1857
11th to 20thDay
14%5%24423436%52%
1900
21st to endDay
15%5%2442345%7%50%
1659
December1st to 10thDay
17%6%34445%46%6%40%
1520
11th to 20thDay
16%424323245%55%
2077
21st to endDay
17%7%35%43345%7%42%
3124
January1st to 10thNight
15%6%25%43435%6%48%
4109
11th to 20thNight
14%6%36%5%345%5%5%44%
4120
21st to endNight
16%7%36%5%33446%44%
4532
February1st to 10thNight
17%6%25%434347%45%
2470
11th to 20thNight
19%6%36%424446%42%
2360
21st to endNight
16%6%24434446%46%
1746
March1st to 10thNight
15%6%34423445%50%
2064
11th to 20thNight
17%435%5%35%5%5%7%41%
1980
21st to endNight
15%5%245%35%5%5%7%44%
2178
April1st to 10thNight
13%5%25%434446%49%
1859
11th to 20thNight
11%425%5%35%35%6%51%
1775
21st to endNight
11%3235%345%6%7%50%
1800
May1st to 10thNight
8%5%25%6%36%5%5%8%47%
1710
11th to 20thNight
12%6%35%5%36%5%5%10%39%
1592
21st to endNight
10%5%246%45%6%7%10%41%
1744
June1st to 10thNight
10%5%35%6%46%6%7%11%39%
1620
11th to 20thNight
11%5%35%6%45%6%7%9%41%
1620
21st to endNight
8%435%6%46%6%9%11%37%
1620
July1st to 10thNight
8%6%46%7%45%6%10%10%34%
1620
11th to 20thNight
7%336%7%47%6%7%13%37%
1620
21st to endNight
7%5%47%6%46%8%7%11%36%
1771
August1st to 10thNight
9%6%37%7%36%6%7%10%34%
1611
11th to 20thNight
10%6%37%7%47%6%8%10%32%
1679
21st to endNight
9%6%35%6%46%7%8%11%35%
1980
September1st to 10thNight
10%426%5%45%5%6%9%45%
1800
11th to 20thNight
12%6%35%5%45%5%6%7%41%
1894
21st to endNight
19%6%36%7%45%436%38%
2031
October1st to 10thNight
15%5%245%24347%50%
2160
11th to 20thNight
14%424423445%54%
2160
21st to endNight
11%424423347%55%
2376
November1st to 10thNight
14%6%34423335%55%
2221
11th to 20thNight
14%6%24324446%50%
2280
21st to endNight
14%42442345%7%51%
2507
December1st to 10thNight
17%7%35%434447%41%
2660
11th to 20thNight
17%6%35%423345%49%
3109
21st to endNight
17%6%25%433446%47%
4532

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
37%36%24%24%6%
2837
11th to 20thDay
35%35%18%30%8%
2840
21st to endDay
44%46%15%22%10%
3124
February1st to 10thDay
40%411%19%20%6%
1710
11th to 20thDay
42%46%18%24%7%
1714
21st to endDay
44%5%9%17%19%6%
1703
March1st to 10thDay
36%49%20%24%7%
2057
11th to 20thDay
41%6%10%20%16%6%
1980
21st to endDay
44%5%11%16%20%4
2178
April1st to 10thDay
29%5%10%24%25%8%
2101
11th to 20thDay
32%6%10%23%20%8%
2134
21st to endDay
34%5%13%22%21%5%
2160
May1st to 10thDay
36%7%15%21%18%3
2265
11th to 20thDay
42%7%13%23%13%2
2305
21st to endDay
38%11%15%21%15%1
2531
June1st to 10thDay
41%10%13%19%15%1
2340
11th to 20thDay
34%10%17%22%14%2
2340
21st to endDay
36%12%17%20%12%3
2340
July1st to 10thDay
39%11%18%20%10%3
2275
11th to 20thDay
38%13%21%19%7%2
2271
21st to endDay
36%14%19%22%8%1
2405
August1st to 10thDay
43%12%18%17%9%1
2314
11th to 20thDay
45%13%15%17%10%1
2201
21st to endDay
41%9%18%21%8%3
2376
September1st to 10thDay
36%10%15%18%17%5%
2160
11th to 20thDay
40%7%11%16%22%4
2062
21st to endDay
46%6%10%18%16%4
1927
October1st to 10thDay
39%410%21%24%3
1800
11th to 20thDay
32%5%9%25%23%6%
1800
21st to endDay
32%47%21%26%10%
1980
November1st to 10thDay
34%48%19%27%9%
1857
11th to 20thDay
35%39%20%25%9%
1900
21st to endDay
35%47%23%23%8%
1659
December1st to 10thDay
44%6%11%19%17%4
1520
11th to 20thDay
35%36%22%25%8%
2074
21st to endDay
42%48%21%23%2
3124
January1st to 10thNight
37%48%19%27%5%
4109
11th to 20thNight
40%6%8%15%24%7%
4120
21st to endNight
42%5%7%15%23%8%
4532
February1st to 10thNight
41%48%20%21%7%
2470
11th to 20thNight
44%5%9%15%20%7%
2362
21st to endNight
39%5%9%18%21%8%
1746
March1st to 10thNight
37%5%8%19%23%9%
2064
11th to 20thNight
42%7%10%15%19%7%
1980
21st to endNight
39%7%12%19%19%5%
2178
April1st to 10thNight
36%5%11%16%24%8%
1859
11th to 20thNight
35%5%10%22%21%8%
1775
21st to endNight
31%7%13%24%20%5%
1800
May1st to 10thNight
34%7%15%22%19%4
1710
11th to 20thNight
40%8%13%23%15%1
1593
21st to endNight
34%10%16%24%13%2
1745
June1st to 10thNight
36%10%19%22%11%1
1620
11th to 20thNight
38%10%18%19%12%2
1620
21st to endNight
38%12%17%21%11%2
1620
July1st to 10thNight
41%12%16%20%9%2
1575
11th to 20thNight
33%14%24%20%8%1
1566
21st to endNight
37%12%21%20%9%
1672
August1st to 10thNight
42%12%20%20%6%
1600
11th to 20thNight
44%12%19%17%7%1
1679
21st to endNight
39%13%18%19%9%2
1980
September1st to 10thNight
36%11%14%20%15%6%
1800
11th to 20thNight
39%8%13%18%19%3
1894
21st to endNight
48%6%11%16%15%3
2031
October1st to 10thNight
35%6%9%21%24%5%
2160
11th to 20thNight
32%5%9%22%24%8%
2160
21st to endNight
30%48%21%26%11%
2376
November1st to 10thNight
34%47%17%28%10%
2221
11th to 20thNight
36%5%9%16%24%11%
2280
21st to endNight
34%47%21%26%8%
2507
December1st to 10thNight
43%6%10%17%18%6%
2660
11th to 20thNight
40%46%20%23%8%
3111
21st to endNight
39%47%22%25%3
4532

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
17%17%42%19%5%
270
11th to 20thDay
18%23%31%21%7%
270
21st to endDay
16%21%38%20%6%
297
February1st to 10thDay
18%15%37%24%6%1
270
11th to 20thDay
32%12%38%17%2
312
21st to endDay
22%15%34%20%7%1
382
March1st to 10thDay
17%16%31%26%10%1
448
11th to 20thDay
19%14%37%23%7%1
420
21st to endDay
18%13%34%25%9%2
462
April1st to 10thDay
17%16%28%24%13%2
420
11th to 20thDay
12%10%30%24%19%6%
412
21st to endDay
16%10%25%24%20%4
420
May1st to 10thDay
10%11%35%23%16%6%
423
11th to 20thDay
15%420%25%28%10%
447
21st to endDay
15%415%25%25%16%
485
June1st to 10thDay
13%216%33%24%12%
450
11th to 20thDay
12%215%25%30%17%
450
21st to endDay
8%313%27%33%16%
450
July1st to 10thDay
11%28%24%32%23%
445
11th to 20thDay
9%29%20%37%23%
444
21st to endDay
6%110%28%39%16%
488
August1st to 10thDay
13%213%21%31%20%
446
11th to 20thDay
12%210%21%30%25%
439
21st to endDay
13%29%24%26%26%
495
September1st to 10thDay
9%212%25%27%24%
450
11th to 20thDay
16%410%24%31%15%
450
21st to endDay
21%418%28%22%8%
450
October1st to 10thDay
17%7%17%23%24%11%
450
11th to 20thDay
14%5%23%28%23%7%
450
21st to endDay
13%8%22%31%20%6%
495
November1st to 10thDay
19%7%23%29%17%5%
455
11th to 20thDay
16%8%31%32%10%2
460
21st to endDay
13%10%30%26%18%2
268
December1st to 10thDay
18%11%38%21%11%1
180
11th to 20thDay
20%8%39%18%12%3
234
21st to endDay
22%14%31%20%10%3
297
January1st to 10thNight
19%11%35%28%7%1
760
11th to 20thNight
17%11%34%31%7%
760
21st to endNight
19%9%39%30%4
836
February1st to 10thNight
19%9%35%32%4
760
11th to 20thNight
23%12%40%24%1
743
21st to endNight
17%13%38%28%5%
628
March1st to 10thNight
18%11%34%32%6%
751
11th to 20thNight
18%10%38%26%8%1
720
21st to endNight
16%10%36%31%7%
792
April1st to 10thNight
15%12%34%31%7%
720
11th to 20thNight
13%9%33%33%12%1
711
21st to endNight
14%6%29%40%10%1
720
May1st to 10thNight
9%8%33%37%13%
630
11th to 20thNight
15%422%41%18%
531
21st to endNight
11%211%41%33%2
584
June1st to 10thNight
11%216%44%26%2
540
11th to 20thNight
11%214%38%29%6%
540
21st to endNight
8%213%41%34%3
540
July1st to 10thNight
8%210%34%42%5%
525
11th to 20thNight
7%27%35%44%6%
522
21st to endNight
8%310%38%39%3
591
August1st to 10thNight
11%39%35%39%4
537
11th to 20thNight
12%210%32%39%5%
615
21st to endNight
11%28%33%39%6%
792
September1st to 10thNight
11%210%30%41%6%
720
11th to 20thNight
13%312%32%35%4
720
21st to endNight
22%416%32%25%2
720
October1st to 10thNight
17%417%31%28%4
720
11th to 20thNight
14%425%32%23%2
720
21st to endNight
14%5%25%34%20%2
792
November1st to 10thNight
15%6%23%36%17%3
740
11th to 20thNight
14%10%27%34%13%1
760
21st to endNight
15%6%28%34%17%1
760
December1st to 10thNight
19%10%28%36%7%
760
11th to 20thNight
19%7%28%36%9%1
760
21st to endNight
19%9%28%35%8%
836
Page generated at 2024-03-05 07:23:59. Version ac07

Copyright © 2024 Attilla Danko.


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