This page made possible by the sponsorship of:
,
,
Lee & Gail Davidson
in memory of
L. Nevil Davy
.

Cherry Springs State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cherry Springs State Park clear sky chart from 2005-11-05 to 2018-03-11.

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
29%
15683
14%
49139
8%
15644
36%
15644
16%
34735

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
11%
778
10%
2683
3%
776
20%
776
7%
2076
January16th to endNight
12%
832
11%
2704
3%
832
21%
832
9%
2078
February1st to 15thNight
9%
764
9%
2482
2%
761
19%
761
7%
1927
February16th to endNight
14%
683
13%
2132
4%
683
25%
683
10%
1577
March1st to 15thNight
16%
764
15%
2121
6%
764
25%
764
12%
1618
March16th to endNight
19%
768
18%
2097
7%
768
28%
768
16%
1502
April1st to 15thNight
19%
718
13%
1796
3%
718
25%
718
16%
1359
April16th to endNight
30%
669
18%
1749
5%
669
36%
669
25%
1167
May1st to 15thNight
34%
477
15%
1557
8%
477
43%
477
17%
1087
May16th to endNight
44%
374
16%
1497
16%
374
50%
374
18%
943
June1st to 15thNight
42%
360
14%
1440
13%
360
51%
360
18%
896
June16th to endNight
46%
360
15%
1440
16%
360
54%
360
22%
862
July1st to 15thNight
52%
340
14%
1360
18%
340
56%
340
25%
790
July16th to endNight
58%
483
16%
1516
16%
452
62%
452
29%
903
August1st to 15thNight
58%
539
16%
1609
11%
536
61%
536
31%
995
August16th to endNight
59%
697
21%
1843
12%
697
62%
697
33%
1158
September1st to 15thNight
46%
720
21%
1800
11%
720
50%
720
29%
1207
September16th to endNight
48%
717
22%
1989
17%
717
52%
717
28%
1301
October1st to 15thNight
36%
720
17%
2160
13%
720
43%
720
23%
1443
October16th to endNight
24%
768
15%
2304
7%
768
34%
768
16%
1662
November1st to 15thNight
28%
760
16%
2488
11%
760
37%
760
19%
1669
November16th to endNight
21%
780
13%
2730
8%
780
30%
780
11%
2011
December1st to 15thNight
15%
780
7%
2730
3%
780
20%
780
7%
2176
December16th to endNight
12%
832
8%
2912
2%
832
20%
832
6%
2328

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
17%9%47%6%35%45%6%29%
49482
Night
15%9%47%6%35%45%6%31%
49319
Cloud CoverDay
17%9%47%6%35%45%6%29%
49492
Night
15%9%46%6%3445%7%32%
49323
TransparencyDay
53%5%10%17%10%1
49180
Night
50%6%12%19%10%1
49139
SeeingDay
23%15%25%18%11%5%
6042
Night
22%16%27%22%10%1
15686

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 15thDay
15%13%8%11%8%345%4419%
1582
16th to endDay
12%15%7%13%9%45%345%18%
1872
February1st to 15thDay
15%17%7%11%9%26%33417%
1710
16th to endDay
17%11%5%10%8%34346%24%
1625
March1st to 15thDay
17%13%5%8%6%24445%25%
2062
16th to endDay
16%11%5%7%6%2335%6%29%
2126
April1st to 15thDay
20%13%5%5%5%2335%5%29%
2152
16th to endDay
19%9%345%34345%37%
2220
May1st to 15thDay
22%8%37%435%345%29%
2394
16th to endDay
18%6%35%7%36%45%7%32%
2618
June1st to 15thDay
17%7%36%6%45%45%7%31%
2520
16th to endDay
16%6%25%6%46%5%5%9%31%
2520
July1st to 15thDay
12%6%36%7%45%5%6%8%32%
2520
16th to endDay
12%5%26%6%47%6%6%8%32%
2545
August1st to 15thDay
14%6%27%6%46%5%6%8%30%
2340
16th to endDay
15%5%36%5%36%6%6%8%32%
2345
September1st to 15thDay
20%7%36%434445%35%
2160
16th to endDay
18%5%26%434345%40%
1970
October1st to 15thDay
20%7%36%4235%5%7%32%
1800
16th to endDay
22%11%46%6%3444426%
1920
November1st to 15thDay
14%12%46%5%35%447%33%
1697
16th to endDay
20%13%5%8%6%34435%24%
1560
December1st to 15thDay
18%15%7%13%6%45%33417%
1560
16th to endDay
19%15%7%10%7%35%46%5%14%
1664
January1st to 15thNight
17%12%410%8%46%5%45%18%
2683
16th to endNight
14%13%6%10%7%46%445%21%
2704
February1st to 15thNight
13%14%7%9%8%46%5%45%21%
2480
16th to endNight
14%11%5%9%8%36%45%7%23%
2132
March1st to 15thNight
16%11%5%7%7%35%446%27%
2109
16th to endNight
15%9%47%5%35%447%32%
2097
April1st to 15thNight
20%9%46%6%34436%29%
1796
16th to endNight
15%9%24424346%40%
1749
May1st to 15thNight
20%7%36%435%445%34%
1557
16th to endNight
13%5%35%5%4445%7%38%
1495
June1st to 15thNight
14%6%25%6%3446%8%37%
1440
16th to endNight
12%5%25%435%5%5%8%41%
1440
July1st to 15thNight
9%5%35%335%46%8%44%
1440
16th to endNight
9%4245%35%45%9%45%
1621
August1st to 15thNight
9%425%5%35%5%6%7%45%
1620
16th to endNight
10%5%2442446%9%45%
1843
September1st to 15thNight
15%6%25%5%23446%44%
1800
16th to endNight
15%5%25%43435%6%43%
1989
October1st to 15thNight
20%6%24433346%39%
2160
16th to endNight
21%10%26%5%3335%6%30%
2304
November1st to 15thNight
15%9%25%6%25%446%36%
2488
16th to endNight
17%12%5%8%6%3445%6%24%
2730
December1st to 15thNight
19%14%6%9%6%36%45%5%18%
2730
16th to endNight
18%13%6%11%8%46%45%6%15%
2912

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
15%13%7%10%9%3445%5%20%
1582
16th to endDay
12%15%7%12%9%46%345%18%
1872
February1st to 15thDay
15%16%7%9%9%35%34418%
1710
16th to endDay
16%12%411%8%24346%25%
1625
March1st to 15thDay
17%12%6%7%6%2445%5%26%
2073
16th to endDay
17%10%5%6%6%34446%30%
2125
April1st to 15thDay
19%13%5%5%424445%29%
2152
16th to endDay
19%8%35%5%34335%37%
2220
May1st to 15thDay
21%9%36%6%34445%30%
2394
16th to endDay
17%7%36%5%35%5%5%7%32%
2618
June1st to 15thDay
17%7%36%6%35%447%32%
2520
16th to endDay
16%6%25%6%36%5%5%8%31%
2520
July1st to 15thDay
12%6%36%6%5%5%46%8%32%
2520
16th to endDay
11%5%36%6%47%6%7%8%32%
2545
August1st to 15thDay
13%5%37%7%5%6%6%5%8%30%
2340
16th to endDay
14%6%35%6%45%7%6%8%32%
2345
September1st to 15thDay
19%7%26%434446%35%
2160
16th to endDay
17%425%5%34445%40%
1970
October1st to 15thDay
20%8%36%5%2335%7%33%
1800
16th to endDay
21%11%37%5%3445%428%
1920
November1st to 15thDay
14%12%35%5%35%446%34%
1697
16th to endDay
20%12%5%7%6%34345%25%
1560
December1st to 15thDay
17%15%6%12%7%35%345%18%
1560
16th to endDay
20%14%6%10%6%35%46%6%15%
1664
January1st to 15thNight
17%12%49%8%36%6%5%6%19%
2683
16th to endNight
14%11%5%9%7%45%6%5%6%22%
2704
February1st to 15thNight
13%14%6%9%7%45%45%5%22%
2473
16th to endNight
14%10%49%8%35%45%7%25%
2132
March1st to 15thNight
16%10%48%7%35%446%28%
2121
16th to endNight
15%9%46%5%34447%33%
2097
April1st to 15thNight
20%10%46%6%34436%30%
1796
16th to endNight
15%8%25%42435%6%41%
1749
May1st to 15thNight
20%7%36%6%24445%34%
1556
16th to endNight
13%6%25%5%35%45%7%39%
1495
June1st to 15thNight
14%5%25%425%5%5%8%38%
1440
16th to endNight
11%425%5%25%5%6%8%41%
1440
July1st to 15thNight
9%6%244346%5%10%44%
1440
16th to endNight
9%3346%345%5%9%44%
1621
August1st to 15thNight
9%5%245%35%5%5%8%45%
1620
16th to endNight
10%5%2443445%9%45%
1843
September1st to 15thNight
15%5%25%42345%6%44%
1800
16th to endNight
15%5%245%24446%44%
1989
October1st to 15thNight
20%6%25%424347%39%
2160
16th to endNight
20%10%26%5%24447%31%
2304
November1st to 15thNight
14%9%35%5%3445%6%37%
2488
16th to endNight
18%11%47%6%35%446%26%
2730
December1st to 15thNight
19%12%6%8%5%36%5%5%6%19%
2730
16th to endNight
18%12%6%9%8%35%5%5%7%16%
2912

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
63%49%13%7%1
1583
16th to endDay
66%412%11%4
1872
February1st to 15thDay
67%49%12%5%
1712
16th to endDay
60%48%18%7%
1625
March1st to 15thDay
58%410%17%7%
2073
16th to endDay
54%48%20%9%2
2126
April1st to 15thDay
56%49%17%11%
2152
16th to endDay
48%5%7%18%18%2
2220
May1st to 15thDay
55%5%10%18%9%1
2394
16th to endDay
49%8%13%15%11%1
2622
June1st to 15thDay
51%6%10%19%10%
2520
16th to endDay
48%6%13%20%10%
2520
July1st to 15thDay
47%6%9%20%13%1
2371
16th to endDay
45%8%14%20%10%1
2387
August1st to 15thDay
48%7%12%19%11%
2327
16th to endDay
46%7%11%19%12%1
2345
September1st to 15thDay
49%5%9%20%14%1
2160
16th to endDay
44%5%8%23%17%1
1970
October1st to 15thDay
50%6%10%18%13%1
1800
16th to endDay
57%5%11%18%6%
1920
November1st to 15thDay
49%5%12%19%10%3
1697
16th to endDay
59%410%17%7%
1560
December1st to 15thDay
68%411%10%4
1560
16th to endDay
67%5%12%11%3
1664
January1st to 15thNight
62%5%11%12%6%1
2683
16th to endNight
59%6%12%15%6%
2704
February1st to 15thNight
61%6%12%14%4
2482
16th to endNight
56%410%18%8%
2132
March1st to 15thNight
56%6%8%21%7%
2121
16th to endNight
49%5%12%19%12%1
2097
April1st to 15thNight
54%5%7%19%11%
1796
16th to endNight
43%410%23%15%3
1749
May1st to 15thNight
50%5%9%22%11%
1557
16th to endNight
42%7%13%19%14%2
1497
June1st to 15thNight
41%7%14%24%12%
1440
16th to endNight
37%8%13%25%14%
1440
July1st to 15thNight
35%7%13%25%16%1
1360
16th to endNight
34%6%17%21%18%1
1516
August1st to 15thNight
34%7%15%28%12%
1609
16th to endNight
34%6%12%27%16%2
1843
September1st to 15thNight
39%6%11%24%15%1
1800
16th to endNight
40%5%11%26%15%1
1989
October1st to 15thNight
45%412%20%15%1
2160
16th to endNight
51%5%14%19%7%
2304
November1st to 15thNight
46%5%15%17%11%3
2488
16th to endNight
57%5%11%17%7%
2730
December1st to 15thNight
63%7%11%12%4
2730
16th to endNight
65%6%12%11%3
2912

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
33%27%25%6%6%1
98
16th to endDay
33%26%27%11%1
144
February1st to 15thDay
37%34%27%
135
16th to endDay
34%22%32%9%
206
March1st to 15thDay
27%25%27%15%3
312
16th to endDay
25%25%25%16%5%2
288
April1st to 15thDay
30%18%25%17%5%2
270
16th to endDay
22%18%26%16%12%3
270
May1st to 15thDay
38%17%18%11%10%4
288
16th to endDay
22%13%28%17%12%6%
331
June1st to 15thDay
20%13%27%24%11%2
315
16th to endDay
20%12%31%21%9%3
315
July1st to 15thDay
15%9%29%24%13%7%
305
16th to endDay
13%5%27%27%18%7%
326
August1st to 15thDay
15%5%26%25%16%10%
313
16th to endDay
15%5%22%22%17%16%
332
September1st to 15thDay
20%7%19%20%20%11%
315
16th to endDay
15%9%16%20%25%12%
314
October1st to 15thDay
21%9%22%24%16%5%
315
16th to endDay
28%17%29%18%5%
336
November1st to 15thDay
23%12%28%20%13%
238
16th to endDay
25%26%28%15%3
90
December1st to 15thDay
32%26%23%11%42
90
16th to endDay
40%35%20%3
96
January1st to 15thNight
27%25%31%12%3
780
16th to endNight
24%26%33%14%
832
February1st to 15thNight
26%25%35%11%1
764
16th to endNight
27%26%30%14%1
683
March1st to 15thNight
26%26%29%15%2
764
16th to endNight
21%23%30%17%5%1
768
April1st to 15thNight
28%18%30%18%3
718
16th to endNight
22%12%31%24%8%1
669
May1st to 15thNight
23%10%23%28%13%
477
16th to endNight
14%10%24%33%16%
375
June1st to 15thNight
18%9%21%36%12%1
360
16th to endNight
11%431%39%12%
360
July1st to 15thNight
12%326%35%20%1
340
16th to endNight
11%218%42%22%2
483
August1st to 15thNight
11%219%39%25%2
539
16th to endNight
11%418%33%28%3
697
September1st to 15thNight
17%7%21%29%22%1
720
16th to endNight
17%8%19%21%26%7%
717
October1st to 15thNight
23%12%22%22%17%2
720
16th to endNight
27%17%28%22%5%
768
November1st to 15thNight
20%14%32%23%7%1
760
16th to endNight
28%17%28%18%5%1
780
December1st to 15thNight
31%21%27%15%4
780
16th to endNight
29%25%28%14%1
832
Page generated at 2018-03-12 13:28:12. Version ac04

Copyright 2018 A. Danko


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