State College
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the State College 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
34%
23199
17%
74800
10%
23150
42%
23150
19%
50608

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%
757
16%
2649
6%
757
28%
757
12%
1853
January11th to 20thNight
19%
739
12%
2399
5%
739
28%
739
11%
1795
January21st to endNight
18%
792
15%
2574
6%
792
29%
792
12%
1874
February1st to 10thNight
19%
720
13%
2340
6%
720
28%
720
12%
1690
February11th to 20thNight
13%
703
14%
2275
3%
700
27%
700
12%
1608
February21st to endNight
17%
592
18%
1792
5%
592
30%
592
13%
1307
March1st to 10thNight
23%
720
21%
1994
9%
720
36%
720
20%
1352
March11th to 20thNight
23%
720
19%
1980
8%
720
32%
720
17%
1403
March21st to endNight
23%
792
19%
2165
7%
792
33%
792
19%
1523
April1st to 10thNight
22%
720
14%
1800
4%
720
28%
720
18%
1331
April11th to 20thNight
29%
711
17%
1775
6%
711
35%
711
24%
1247
April21st to endNight
30%
667
18%
1747
6%
667
37%
667
23%
1211
May1st to 10thNight
36%
540
15%
1620
9%
540
42%
540
19%
1145
May11th to 20thNight
36%
387
17%
1449
12%
387
46%
387
18%
942
May21st to endNight
50%
388
17%
1551
16%
388
56%
388
21%
922
June1st to 10thNight
50%
360
18%
1440
19%
360
57%
360
22%
837
June11th to 20thNight
48%
360
15%
1440
16%
360
54%
360
20%
881
June21st to endNight
54%
360
17%
1440
19%
360
61%
360
25%
835
July1st to 10thNight
54%
350
16%
1400
17%
350
58%
350
21%
835
July11th to 20thNight
63%
365
19%
1409
23%
365
65%
365
29%
768
July21st to endNight
58%
591
17%
1672
13%
558
62%
558
31%
1037
August1st to 10thNight
63%
537
17%
1600
13%
534
65%
534
31%
989
August11th to 20thNight
59%
538
18%
1602
13%
538
61%
538
27%
1043
August21st to endNight
58%
792
20%
1980
12%
792
60%
792
33%
1320
September1st to 10thNight
53%
720
21%
1800
11%
720
57%
720
31%
1192
September11th to 20thNight
57%
720
28%
1807
19%
720
61%
720
37%
1129
September21st to endNight
47%
720
22%
2074
17%
720
51%
720
26%
1362
October1st to 10thNight
46%
720
18%
2160
15%
720
52%
720
26%
1372
October11th to 20thNight
36%
720
18%
2160
13%
720
45%
720
23%
1407
October21st to endNight
31%
792
20%
2376
12%
792
42%
792
20%
1611
November1st to 10thNight
41%
740
23%
2333
16%
740
52%
740
27%
1394
November11th to 20thNight
28%
760
19%
2603
11%
760
39%
760
16%
1726
November21st to endNight
27%
760
17%
2660
10%
760
38%
760
16%
1808
December1st to 10thNight
21%
760
12%
2660
6%
760
30%
760
11%
1952
December11th to 20thNight
23%
760
12%
3231
5%
759
32%
759
9%
2305
December21st to endNight
22%
826
8%
4843
6%
817
31%
817
6%
3602

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
15%9%47%6%45%5%5%7%33%
74692
Night
15%8%47%6%35%5%5%7%36%
75089
TransparencyDay
49%6%11%20%12%2
74402
Night
46%6%12%22%12%2
74898
SeeingDay
22%15%27%21%11%4
13637
Night
21%13%25%29%11%1
23213

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
12%11%5%10%7%5%6%5%46%29%
1517
11th to 20thDay
14%14%6%11%8%5%6%5%45%22%
1652
21st to endDay
13%15%6%11%9%5%5%5%45%22%
1782
February1st to 10thDay
16%15%6%8%8%5%5%447%22%
1620
11th to 20thDay
14%10%5%11%8%45%46%7%25%
1573
21st to endDay
17%12%49%7%44445%29%
1463
March1st to 10thDay
13%11%48%6%4445%6%35%
1962
11th to 20thDay
17%11%48%7%35%45%7%29%
1980
21st to endDay
18%10%47%6%44446%34%
2191
April1st to 10thDay
15%9%5%7%6%45%5%47%33%
2160
11th to 20thDay
15%10%46%5%45%5%5%7%35%
2134
21st to endDay
20%7%47%5%45%45%6%33%
2227
May1st to 10thDay
19%9%36%7%35%5%5%7%31%
2340
11th to 20thDay
21%8%36%6%35%45%7%33%
2442
21st to endDay
14%7%25%5%36%6%6%8%37%
2725
June1st to 10thDay
13%7%37%6%36%6%6%7%35%
2520
11th to 20thDay
14%6%36%6%36%6%6%9%35%
2520
21st to endDay
12%5%25%5%45%6%6%10%38%
2520
July1st to 10thDay
10%7%26%6%46%6%7%9%36%
2520
11th to 20thDay
9%5%36%5%5%6%7%7%9%38%
2500
21st to endDay
10%7%36%6%45%7%7%9%35%
2547
August1st to 10thDay
9%6%27%7%5%6%7%8%10%32%
2327
11th to 20thDay
14%6%37%6%47%6%7%8%33%
2281
21st to endDay
13%6%27%6%45%5%7%9%35%
2376
September1st to 10thDay
17%6%26%5%345%46%41%
2160
11th to 20thDay
15%5%2443445%8%47%
2150
21st to endDay
18%8%36%425%5%6%6%37%
1884
October1st to 10thDay
16%7%37%5%36%447%38%
1800
11th to 20thDay
18%8%36%6%35%5%6%6%35%
1800
21st to endDay
18%10%37%5%345%5%7%34%
1980
November1st to 10thDay
11%7%36%5%45%6%5%6%42%
1743
11th to 20thDay
16%11%47%7%35%5%5%6%32%
1574
21st to endDay
17%10%5%7%7%35%5%6%6%29%
1520
December1st to 10thDay
18%14%5%9%7%45%5%46%22%
1520
11th to 20thDay
18%14%7%7%5%445%46%26%
1910
21st to endDay
21%17%6%10%7%45%5%5%416%
2772
January1st to 10thNight
13%11%6%9%7%45%6%6%7%27%
2649
11th to 20thNight
16%12%5%9%6%5%5%5%5%6%26%
2399
21st to endNight
13%12%5%9%8%5%5%5%5%5%29%
2574
February1st to 10thNight
16%11%5%8%6%35%5%5%6%29%
2340
11th to 20thNight
17%9%38%7%46%6%5%6%29%
2273
21st to endNight
16%12%48%7%45%445%32%
1792
March1st to 10thNight
14%7%46%5%35%5%6%6%38%
1994
11th to 20thNight
17%10%46%6%34445%37%
1980
21st to endNight
17%9%37%6%3435%6%37%
2165
April1st to 10thNight
17%11%6%7%6%245%46%33%
1800
11th to 20thNight
16%7%46%6%35%6%5%7%38%
1775
21st to endNight
17%7%26%6%345%5%8%37%
1747
May1st to 10thNight
18%9%35%6%36%5%5%6%35%
1620
11th to 20thNight
17%7%35%5%35%45%7%39%
1448
21st to endNight
12%6%36%5%3446%11%41%
1550
June1st to 10thNight
12%6%35%4245%5%9%43%
1440
11th to 20thNight
12%6%27%6%45%5%7%9%38%
1440
21st to endNight
11%5%345%345%6%12%42%
1440
July1st to 10thNight
10%5%25%5%35%46%8%44%
1440
11th to 20thNight
7%4345%345%7%11%46%
1457
21st to endNight
10%5%26%5%45%5%7%10%42%
1771
August1st to 10thNight
7%7%35%5%35%5%7%9%45%
1611
11th to 20thNight
12%6%36%6%35%46%6%42%
1602
21st to endNight
11%6%35%5%345%6%9%43%
1980
September1st to 10thNight
16%5%245%35%5%5%7%45%
1800
11th to 20thNight
11%6%2443345%7%51%
1807
21st to endNight
16%6%26%6%3445%7%42%
2074
October1st to 10thNight
17%6%25%5%2445%8%43%
2160
11th to 20thNight
16%7%25%6%3445%7%41%
2160
21st to endNight
20%9%45%42446%6%37%
2376
November1st to 10thNight
10%7%26%5%24447%49%
2333
11th to 20thNight
16%9%46%5%35%45%7%35%
2603
21st to endNight
16%9%5%7%5%35%5%5%6%33%
2660
December1st to 10thNight
18%11%5%7%6%46%5%5%7%26%
2660
11th to 20thNight
18%11%49%6%45%5%5%6%29%
3285
21st to endNight
18%13%5%9%8%46%5%6%6%21%
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
55%5%13%18%8%1
1518
11th to 20thDay
63%6%11%13%7%1
1652
21st to endDay
64%5%9%15%6%1
1782
February1st to 10thDay
62%5%11%14%6%1
1620
11th to 20thDay
57%5%10%21%6%1
1582
21st to endDay
57%410%19%8%2
1463
March1st to 10thDay
49%5%12%23%10%1
1962
11th to 20thDay
55%5%9%19%10%3
1980
21st to endDay
52%48%19%14%2
2191
April1st to 10thDay
50%5%10%20%12%2
2160
11th to 20thDay
48%6%8%19%16%3
2134
21st to endDay
51%5%8%20%13%2
2227
May1st to 10thDay
52%6%9%19%12%2
2340
11th to 20thDay
50%6%11%17%13%2
2446
21st to endDay
43%8%15%21%11%2
2725
June1st to 10thDay
45%7%12%22%14%1
2520
11th to 20thDay
45%7%13%21%13%2
2520
21st to endDay
39%8%13%27%13%1
2520
July1st to 10thDay
42%10%12%21%13%3
2450
11th to 20thDay
38%9%12%24%15%1
2425
21st to endDay
41%8%12%22%17%1
2405
August1st to 10thDay
42%10%14%22%12%
2314
11th to 20thDay
45%8%12%22%12%1
2281
21st to endDay
43%8%9%23%14%3
2376
September1st to 10thDay
43%6%10%23%16%3
2160
11th to 20thDay
36%5%11%27%19%2
2150
21st to endDay
45%6%11%20%17%1
1884
October1st to 10thDay
46%6%11%21%15%1
1800
11th to 20thDay
48%6%10%24%11%
1800
21st to endDay
49%6%12%21%11%1
1980
November1st to 10thDay
40%6%13%21%16%3
1743
11th to 20thDay
53%5%9%20%9%2
1574
21st to endDay
53%7%11%21%7%
1520
December1st to 10thDay
62%6%12%14%5%
1520
11th to 20thDay
58%6%13%19%5%
1906
21st to endDay
69%6%10%12%3
2772
January1st to 10thNight
53%5%11%21%9%1
2649
11th to 20thNight
58%5%13%15%7%1
2399
21st to endNight
56%5%11%18%10%1
2574
February1st to 10thNight
55%5%12%20%8%1
2340
11th to 20thNight
52%6%11%20%11%1
2275
21st to endNight
55%5%8%19%11%1
1792
March1st to 10thNight
43%6%10%26%13%1
1994
11th to 20thNight
49%5%10%21%13%2
1980
21st to endNight
49%49%19%16%3
2165
April1st to 10thNight
53%49%19%14%2
1800
11th to 20thNight
45%6%10%22%15%2
1775
21st to endNight
45%5%9%22%14%3
1747
May1st to 10thNight
49%6%10%20%12%4
1620
11th to 20thNight
44%8%11%19%16%2
1449
21st to endNight
38%7%15%23%13%3
1551
June1st to 10thNight
38%6%13%25%15%2
1440
11th to 20thNight
40%8%13%22%15%2
1440
21st to endNight
35%8%13%29%15%1
1440
July1st to 10thNight
37%9%12%23%15%3
1400
11th to 20thNight
30%9%15%26%18%1
1409
21st to endNight
34%8%17%22%16%2
1672
August1st to 10thNight
34%9%17%25%15%1
1600
11th to 20thNight
40%7%15%21%16%1
1602
21st to endNight
37%8%13%24%16%3
1980
September1st to 10thNight
38%7%11%24%17%3
1800
11th to 20thNight
32%6%11%30%20%2
1807
21st to endNight
42%5%11%23%18%1
2074
October1st to 10thNight
40%6%13%25%15%1
2160
11th to 20thNight
42%6%13%25%14%1
2160
21st to endNight
47%5%10%23%14%1
2376
November1st to 10thNight
36%5%13%25%18%3
2333
11th to 20thNight
48%5%10%22%13%3
2603
21st to endNight
49%6%12%23%9%1
2660
December1st to 10thNight
55%7%12%18%7%
2660
11th to 20thNight
55%6%11%20%7%
3288
21st to endNight
60%7%12%17%4
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
26%28%27%12%5%2
180
11th to 20thDay
34%22%30%12%11
250
21st to endDay
26%23%35%11%41
264
February1st to 10thDay
29%24%35%11%1
240
11th to 20thDay
36%23%34%7%
240
21st to endDay
35%20%27%16%2
329
March1st to 10thDay
29%22%28%19%3
420
11th to 20thDay
29%21%29%15%41
420
21st to endDay
27%20%30%15%5%2
462
April1st to 10thDay
26%21%27%19%5%1
420
11th to 20thDay
21%23%24%18%10%4
412
21st to endDay
30%16%32%13%8%2
420
May1st to 10thDay
28%18%27%14%10%3
423
11th to 20thDay
23%18%28%16%12%3
447
21st to endDay
19%9%27%22%17%6%
485
June1st to 10thDay
18%13%28%26%12%3
450
11th to 20thDay
20%11%25%27%14%3
450
21st to endDay
14%11%29%29%13%3
450
July1st to 10thDay
14%8%21%28%18%10%
445
11th to 20thDay
9%5%28%31%20%7%
444
21st to endDay
14%7%28%28%16%6%
488
August1st to 10thDay
10%7%24%26%24%8%
446
11th to 20thDay
13%5%24%27%20%11%
439
21st to endDay
15%7%23%28%15%12%
495
September1st to 10thDay
18%7%20%27%19%8%
450
11th to 20thDay
16%5%20%28%22%9%
450
21st to endDay
21%12%24%22%15%6%
450
October1st to 10thDay
21%10%19%25%20%4
450
11th to 20thDay
21%16%28%23%10%1
450
21st to endDay
24%14%32%23%6%1
495
November1st to 10thDay
17%16%28%26%12%2
401
11th to 20thDay
24%23%28%17%7%1
234
21st to endDay
22%24%34%16%31
180
December1st to 10thDay
29%25%31%9%41
180
11th to 20thDay
27%24%27%19%2
180
21st to endDay
28%22%28%16%5%
198
January1st to 10thNight
22%22%34%18%3
760
11th to 20thNight
28%16%29%23%3
739
21st to endNight
22%21%32%23%3
792
February1st to 10thNight
28%18%28%24%2
720
11th to 20thNight
27%24%32%16%1
703
21st to endNight
28%19%31%20%2
592
March1st to 10thNight
24%16%33%24%3
720
11th to 20thNight
27%16%29%23%5%
720
21st to endNight
24%16%32%22%6%1
792
April1st to 10thNight
25%18%29%22%5%
720
11th to 20thNight
22%13%32%25%8%1
711
21st to endNight
24%12%28%30%7%
667
May1st to 10thNight
23%9%24%31%12%1
540
11th to 20thNight
18%11%29%33%9%
387
21st to endNight
15%6%21%34%22%1
389
June1st to 10thNight
15%5%22%39%19%1
360
11th to 20thNight
14%7%22%40%18%
360
21st to endNight
11%6%23%44%16%1
360
July1st to 10thNight
13%418%40%22%3
350
11th to 20thNight
7%219%41%29%2
365
21st to endNight
11%418%45%22%1
591
August1st to 10thNight
9%216%44%27%2
537
11th to 20thNight
14%5%12%37%27%4
538
21st to endNight
14%317%33%30%3
792
September1st to 10thNight
18%416%35%24%3
720
11th to 20thNight
14%5%17%30%28%5%
720
21st to endNight
19%8%20%29%21%3
720
October1st to 10thNight
20%7%21%29%21%3
720
11th to 20thNight
21%13%23%32%11%1
720
21st to endNight
24%15%24%30%6%1
792
November1st to 10thNight
16%11%27%34%12%1
740
11th to 20thNight
24%18%24%25%8%1
760
21st to endNight
23%17%27%28%5%1
760
December1st to 10thNight
27%17%30%20%5%
760
11th to 20thNight
26%17%28%25%4
760
21st to endNight
25%16%29%27%3
836
Page generated at 2024-01-12 07:31:52. Version ac07

Copyright 2024 Attilla Danko


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