Chestnut Ridge Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chestnut Ridge Park clear sky chart from 2005-11-05 to

2017-09-12
.

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
35%
15251
15%
46890
10%
15214
40%
15214
17%
33607

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
13%
716
10%
2327
4%
716
20%
716
7%
1908
January16th to endNight
13%
768
9%
2496
4%
768
20%
768
7%
2022
February1st to 15thNight
16%
702
9%
2287
4%
701
22%
701
10%
1781
February16th to endNight
13%
631
12%
1931
3%
631
22%
631
9%
1535
March1st to 15thNight
21%
720
14%
1980
8%
720
27%
720
13%
1542
March16th to endNight
22%
768
16%
2112
8%
768
30%
768
17%
1558
April1st to 15thNight
24%
718
13%
1849
5%
718
29%
718
18%
1391
April16th to endNight
34%
617
18%
1697
8%
617
40%
617
24%
1177
May1st to 15thNight
37%
540
14%
1620
8%
540
42%
540
18%
1159
May16th to endNight
52%
486
15%
1609
13%
486
55%
486
24%
1023
June1st to 15thNight
53%
360
16%
1440
18%
360
59%
360
22%
880
June16th to endNight
55%
360
16%
1440
18%
360
59%
360
21%
887
July1st to 15thNight
57%
468
11%
1488
11%
468
59%
468
25%
986
July16th to endNight
65%
564
16%
1595
14%
531
67%
531
30%
988
August1st to 15thNight
65%
539
18%
1609
15%
536
65%
536
28%
1028
August16th to endNight
67%
658
24%
1804
18%
658
68%
658
37%
1090
September1st to 15thNight
56%
707
23%
1809
15%
707
59%
707
31%
1208
September16th to endNight
52%
657
24%
1820
19%
657
56%
657
31%
1157
October1st to 15thNight
45%
660
21%
1980
19%
660
51%
660
24%
1307
October16th to endNight
32%
704
18%
2112
12%
704
40%
704
18%
1481
November1st to 15thNight
41%
700
22%
2181
18%
700
48%
700
23%
1428
November16th to endNight
23%
720
14%
2520
10%
720
30%
720
11%
1874
December1st to 15thNight
19%
720
8%
2520
6%
720
22%
720
7%
2065
December16th to endNight
13%
768
9%
2664
4%
768
21%
768
8%
2132

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
19%9%46%5%34446%30%
47744
Night
18%10%46%424446%33%
47083
Cloud CoverDay
18%10%46%5%34446%30%
47754
Night
18%10%46%5%24446%32%
47087
TransparencyDay
53%5%10%18%10%1
47455
Night
52%5%10%19%11%1
46890
SeeingDay
25%11%21%20%14%6%
5467
Night
25%12%22%25%13%1
15259

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
22%14%8%11%6%34235%17%
1611
16th to endDay
21%19%6%9%6%4222320%
1728
February1st to 15thDay
21%15%8%9%5%3433420%
1575
16th to endDay
18%19%5%10%425%33422%
1537
March1st to 15thDay
20%14%5%7%5%23245%28%
1969
16th to endDay
23%12%46%42335%5%27%
2112
April1st to 15thDay
20%11%45%425%346%31%
2098
16th to endDay
22%8%35%42445%6%34%
2274
May1st to 15thDay
24%7%35%6%35%446%27%
2331
16th to endDay
19%6%25%5%35%45%7%33%
2503
June1st to 15thDay
16%425%5%35%5%5%8%36%
2520
16th to endDay
18%5%26%5%46%5%6%9%29%
2520
July1st to 15thDay
17%5%35%7%46%46%7%32%
2379
16th to endDay
14%5%35%5%36%5%6%9%33%
2465
August1st to 15thDay
15%6%26%6%35%6%7%8%31%
2340
16th to endDay
13%4345%445%6%9%38%
2384
September1st to 15thDay
18%5%3342335%7%42%
2068
16th to endDay
19%6%25%5%24446%37%
1810
October1st to 15thDay
23%5%24423446%37%
1650
16th to endDay
25%9%2442333436%
1760
November1st to 15thDay
14%11%3442335%6%38%
1673
16th to endDay
21%14%5%5%5%23245%28%
1440
December1st to 15thDay
24%15%8%9%5%2322320%
1440
16th to endDay
23%18%8%9%42322418%
1557
January1st to 15thNight
23%17%7%8%43333418%
2327
16th to endNight
20%19%6%8%6%4322321%
2496
February1st to 15thNight
19%14%6%10%6%3333424%
2285
16th to endNight
18%16%49%6%35%44422%
1931
March1st to 15thNight
21%12%6%6%5%24345%26%
1968
16th to endNight
22%10%36%423345%32%
2112
April1st to 15thNight
22%11%35%413436%32%
1849
16th to endNight
17%6%25%5%24347%39%
1697
May1st to 15thNight
21%6%35%5%35%46%7%31%
1620
16th to endNight
14%5%2443436%7%41%
1607
June1st to 15thNight
12%5%245%25%46%11%40%
1440
16th to endNight
13%5%23425%5%7%9%39%
1440
July1st to 15thNight
13%5%36%32446%10%38%
1578
16th to endNight
13%433425%6%5%9%42%
1703
August1st to 15thNight
10%425%436%6%8%8%40%
1620
16th to endNight
9%42332445%8%50%
1804
September1st to 15thNight
15%42443345%5%46%
1809
16th to endNight
15%42442335%6%46%
1820
October1st to 15thNight
19%42442445%6%40%
1980
16th to endNight
26%6%2342445%435%
2112
November1st to 15thNight
19%7%2432334442%
2181
16th to endNight
19%13%47%5%2434428%
2520
December1st to 15thNight
24%15%7%9%5%3433417%
2520
16th to endNight
21%18%7%8%423235%20%
2664

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
21%14%8%12%7%3324417%
1611
16th to endDay
20%19%7%9%6%3323420%
1728
February1st to 15thDay
21%15%7%10%5%4433419%
1575
16th to endDay
18%19%6%10%42433421%
1537
March1st to 15thDay
20%15%5%6%5%23335%27%
1980
16th to endDay
22%13%36%5%2435%6%27%
2111
April1st to 15thDay
19%12%45%424346%31%
2098
16th to endDay
21%9%35%4245%46%34%
2274
May1st to 15thDay
22%8%37%6%345%46%26%
2331
16th to endDay
17%6%35%6%36%45%7%32%
2503
June1st to 15thDay
15%425%5%35%5%6%8%35%
2520
16th to endDay
17%5%36%5%36%6%6%9%29%
2520
July1st to 15thDay
17%5%26%7%46%5%5%7%31%
2379
16th to endDay
13%6%36%5%36%6%6%9%31%
2465
August1st to 15thDay
13%7%36%6%36%6%7%9%28%
2340
16th to endDay
13%425%5%346%7%9%37%
2384
September1st to 15thDay
17%6%2442445%6%41%
2068
16th to endDay
18%7%26%5%34436%37%
1810
October1st to 15thDay
22%6%24433346%37%
1650
16th to endDay
24%10%25%32333435%
1760
November1st to 15thDay
14%11%45%423446%38%
1673
16th to endDay
21%15%5%6%423345%27%
1440
December1st to 15thDay
24%16%7%11%6%2313319%
1440
16th to endDay
23%18%9%9%5%22325%17%
1557
January1st to 15thNight
23%16%8%9%5%3332319%
2327
16th to endNight
19%19%7%9%6%3332320%
2496
February1st to 15thNight
18%14%6%10%6%3333423%
2278
16th to endNight
17%16%5%10%6%35%445%22%
1931
March1st to 15thNight
21%11%6%6%6%34345%26%
1980
16th to endNight
21%12%36%423446%31%
2112
April1st to 15thNight
20%11%46%42345%5%32%
1849
16th to endNight
16%7%35%5%2435%7%38%
1697
May1st to 15thNight
21%6%345%345%5%7%31%
1619
16th to endNight
14%6%345%2346%8%40%
1607
June1st to 15thNight
11%5%25%5%345%6%10%40%
1440
16th to endNight
13%5%25%425%5%7%9%39%
1440
July1st to 15thNight
13%6%35%4246%6%9%37%
1578
16th to endNight
11%5%334246%6%9%41%
1703
August1st to 15thNight
9%5%15%5%35%7%8%9%39%
1620
16th to endNight
9%5%134245%48%50%
1804
September1st to 15thNight
14%5%25%42445%445%
1809
16th to endNight
15%4245%2345%6%45%
1820
October1st to 15thNight
18%5%2443445%7%40%
1980
16th to endNight
26%7%23424445%34%
2112
November1st to 15thNight
19%8%24313345%41%
2181
16th to endNight
18%15%5%7%6%23445%27%
2520
December1st to 15thNight
24%16%8%9%5%2433417%
2520
16th to endNight
20%18%8%7%423345%19%
2664

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
70%48%11%31
1612
16th to endDay
70%28%14%3
1728
February1st to 15thDay
69%310%12%4
1577
16th to endDay
65%49%12%7%
1537
March1st to 15thDay
59%5%9%17%7%
1980
16th to endDay
57%5%8%18%9%1
2112
April1st to 15thDay
53%5%8%18%13%1
2098
16th to endDay
51%49%17%14%3
2274
May1st to 15thDay
57%6%9%16%9%
2331
16th to endDay
49%6%12%21%7%1
2507
June1st to 15thDay
44%8%12%22%11%
2520
16th to endDay
49%8%11%19%9%
2520
July1st to 15thDay
51%6%9%18%11%2
2240
16th to endDay
45%8%11%21%12%1
2310
August1st to 15thDay
48%6%11%22%10%
2327
16th to endDay
40%6%12%25%12%2
2384
September1st to 15thDay
41%5%9%22%18%2
2068
16th to endDay
48%46%21%18%
1810
October1st to 15thDay
48%6%10%21%12%1
1650
16th to endDay
52%39%21%11%
1760
November1st to 15thDay
46%49%19%15%4
1673
16th to endDay
59%210%15%11%
1440
December1st to 15thDay
70%38%11%41
1440
16th to endDay
71%38%10%5%
1557
January1st to 15thNight
70%38%9%6%1
2327
16th to endNight
69%39%12%4
2496
February1st to 15thNight
64%39%14%6%
2287
16th to endNight
65%47%16%6%
1931
March1st to 15thNight
60%48%19%6%1
1980
16th to endNight
54%39%21%8%1
2112
April1st to 15thNight
54%48%17%13%1
1849
16th to endNight
45%5%10%18%14%5%
1697
May1st to 15thNight
50%6%12%17%11%1
1620
16th to endNight
39%7%16%21%12%2
1609
June1st to 15thNight
37%9%13%26%12%
1440
16th to endNight
39%8%14%21%14%1
1440
July1st to 15thNight
41%7%14%19%14%2
1488
16th to endNight
34%8%13%25%16%1
1595
August1st to 15thNight
36%8%15%22%15%1
1609
16th to endNight
31%6%11%31%15%3
1804
September1st to 15thNight
39%5%10%21%19%3
1809
16th to endNight
38%48%25%21%
1820
October1st to 15thNight
43%5%9%23%15%2
1980
16th to endNight
50%47%24%11%
2112
November1st to 15thNight
45%39%19%15%6%
2181
16th to endNight
58%47%15%11%1
2520
December1st to 15thNight
70%47%11%41
2520
16th to endNight
67%411%13%3
2664

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
32%37%12%10%6%1
90
16th to endDay
47%18%26%6%1
96
February1st to 15thDay
35%37%24%2
90
16th to endDay
33%26%30%7%
115
March1st to 15thDay
31%20%26%15%5%
270
16th to endDay
32%15%28%14%5%2
288
April1st to 15thDay
30%16%23%20%7%1
270
16th to endDay
27%12%27%16%11%5%
270
May1st to 15thDay
36%14%20%14%9%5%
288
16th to endDay
24%11%18%20%13%10%
331
June1st to 15thDay
17%7%21%26%20%7%
315
16th to endDay
23%9%22%21%17%6%
315
July1st to 15thDay
24%423%27%11%8%
305
16th to endDay
13%6%15%25%26%11%
326
August1st to 15thDay
15%418%26%23%11%
313
16th to endDay
15%117%23%25%16%
332
September1st to 15thDay
19%6%17%22%22%12%
299
16th to endDay
19%9%16%21%23%9%
254
October1st to 15thDay
24%7%18%29%18%2
255
16th to endDay
31%12%24%23%7%
272
November1st to 15thDay
20%9%19%29%16%3
186
16th to endDay
33%25%20%11%6%3
60
December1st to 15thDay
45%26%18%333
60
16th to endDay
50%20%17%10%
67
January1st to 15thNight
36%21%25%14%2
720
16th to endNight
34%23%23%17%1
768
February1st to 15thNight
30%20%29%18%1
704
16th to endNight
29%24%29%16%
631
March1st to 15thNight
31%17%25%19%5%
720
16th to endNight
26%17%30%18%6%
768
April1st to 15thNight
29%14%28%20%6%
718
16th to endNight
21%9%29%25%13%
617
May1st to 15thNight
24%9%23%30%11%
540
16th to endNight
18%319%30%25%3
488
June1st to 15thNight
12%420%37%23%1
360
16th to endNight
14%220%39%21%1
360
July1st to 15thNight
17%115%38%23%3
468
16th to endNight
14%111%30%37%4
564
August1st to 15thNight
12%110%41%30%3
539
16th to endNight
11%110%37%34%3
658
September1st to 15thNight
18%315%31%27%3
707
16th to endNight
18%5%17%27%28%3
657
October1st to 15thNight
21%7%21%28%18%2
660
16th to endNight
31%11%20%27%8%
704
November1st to 15thNight
25%10%19%30%13%1
700
16th to endNight
30%17%21%23%5%1
720
December1st to 15thNight
35%18%21%19%5%
720
16th to endNight
33%18%27%19%1
768
Page generated at 2017-09-13 07:39:15. Version ac04

Copyright 2017 A. Danko


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