Robert Moses State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Robert Moses State Park clear sky chart from 2005-11-05 to 2017-08-12.

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
33%
14901
18%
46477
9%
14870
43%
14870
20%
30240

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
19%
720
19%
2506
8%
716
34%
716
15%
1602
January16th to endNight
16%
768
19%
2622
6%
768
33%
768
15%
1676
February1st to 15thNight
16%
704
16%
2189
4%
701
30%
701
17%
1463
February16th to endNight
21%
631
24%
1893
9%
631
41%
631
20%
1200
March1st to 15thNight
22%
720
18%
2160
8%
720
35%
720
20%
1413
March16th to endNight
25%
768
23%
1999
8%
768
37%
768
24%
1326
April1st to 15thNight
29%
718
17%
1796
6%
718
35%
718
23%
1238
April16th to endNight
33%
681
17%
1761
6%
681
40%
681
23%
1217
May1st to 15thNight
33%
540
16%
1620
7%
540
40%
540
17%
1136
May16th to endNight
41%
381
15%
1504
14%
381
47%
381
14%
983
June1st to 15thNight
42%
360
14%
1440
15%
360
48%
360
16%
934
June16th to endNight
55%
360
14%
1440
15%
360
62%
360
21%
840
July1st to 15thNight
52%
340
12%
1360
15%
340
54%
340
19%
842
July16th to endNight
53%
376
16%
1418
16%
354
62%
354
20%
836
August1st to 15thNight
58%
545
19%
1594
13%
543
61%
543
28%
978
August16th to endNight
61%
700
17%
1750
9%
700
63%
700
31%
1159
September1st to 15thNight
53%
660
23%
1664
14%
660
56%
660
31%
1111
September16th to endNight
50%
657
23%
1815
15%
657
56%
657
28%
1154
October1st to 15thNight
37%
660
21%
1895
14%
660
45%
660
23%
1252
October16th to endNight
29%
704
18%
2222
8%
704
43%
704
21%
1444
November1st to 15thNight
28%
700
20%
2277
12%
700
41%
700
20%
1426
November16th to endNight
25%
720
17%
2344
8%
720
37%
720
17%
1525
December1st to 15thNight
20%
720
13%
2520
5%
720
30%
720
12%
1704
December16th to endNight
15%
768
18%
2688
4%
768
32%
768
13%
1781

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%5%2442445%7%42%
47509
Night
16%6%24424447%41%
46647
Cloud CoverDay
15%5%2442445%7%42%
47519
Night
16%6%2442445%7%41%
46652
TransparencyDay
39%6%13%22%15%1
47197
Night
42%5%12%21%15%2
46477
SeeingDay
17%13%20%28%16%3
5714
Night
17%21%23%24%12%1
14902

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%6%25%5%3435%5%41%
1432
16th to endDay
15%6%34423449%41%
1601
February1st to 15thDay
16%5%25%43435%7%40%
1672
16th to endDay
14%5%25%5%35%35%6%42%
1580
March1st to 15thDay
17%7%24424448%39%
1790
16th to endDay
17%7%33423345%43%
2223
April1st to 15thDay
18%5%34424347%41%
2152
16th to endDay
16%6%2432345%6%43%
2199
May1st to 15thDay
20%7%235%34348%37%
2335
16th to endDay
17%5%244245%5%8%38%
2618
June1st to 15thDay
19%5%24324448%39%
2520
16th to endDay
10%3245%35%5%5%8%46%
2520
July1st to 15thDay
8%4345%35%5%6%8%43%
2520
16th to endDay
11%424435%5%6%9%42%
2654
August1st to 15thDay
9%42432446%8%48%
2258
16th to endDay
12%32432346%6%49%
2100
September1st to 15thDay
12%42442346%7%47%
1966
16th to endDay
14%5%24422347%46%
1815
October1st to 15thDay
17%6%14424346%43%
1733
16th to endDay
17%42332436%7%44%
1650
November1st to 15thDay
18%5%24333335%46%
1581
16th to endDay
14%5%25%5%2446%8%41%
1614
December1st to 15thDay
17%7%24335%5%6%5%39%
1440
16th to endDay
22%7%2442345%6%35%
1536
January1st to 15thNight
18%5%24424347%40%
2506
16th to endNight
18%7%23324436%41%
2622
February1st to 15thNight
15%8%35%4245%5%6%39%
2188
16th to endNight
17%5%23424347%44%
1893
March1st to 15thNight
18%6%25%423347%43%
2147
16th to endNight
17%7%33313346%45%
1999
April1st to 15thNight
18%7%24334447%39%
1796
16th to endNight
18%7%245%2235%7%39%
1761
May1st to 15thNight
18%8%35%435%346%35%
1620
16th to endNight
20%5%26%32445%8%35%
1502
June1st to 15thNight
21%425%323447%39%
1440
16th to endNight
9%425%5%345%5%11%42%
1440
July1st to 15thNight
11%5%245%35%5%7%9%38%
1440
16th to endNight
10%435%425%6%7%8%40%
1514
August1st to 15thNight
8%4244346%6%8%45%
1604
16th to endNight
12%4245%3445%9%43%
1750
September1st to 15thNight
14%42442446%6%45%
1664
16th to endNight
15%5%25%433345%48%
1815
October1st to 15thNight
17%6%25%423335%43%
1895
16th to endNight
18%5%15%433336%43%
2222
November1st to 15thNight
17%6%24423235%47%
2277
16th to endNight
17%6%25%42445%6%40%
2344
December1st to 15thNight
20%7%25%42335%7%36%
2520
16th to endNight
20%6%25%42345%6%37%
2688

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%7%15%434346%40%
1432
16th to endDay
15%7%24424349%40%
1601
February1st to 15thDay
16%5%36%435%35%6%40%
1672
16th to endDay
14%5%25%5%3445%6%42%
1580
March1st to 15thDay
17%7%2442345%8%38%
1800
16th to endDay
17%7%23423345%43%
2223
April1st to 15thDay
18%5%34423347%42%
2152
16th to endDay
16%6%1442345%6%43%
2199
May1st to 15thDay
20%7%2343425%7%37%
2335
16th to endDay
16%5%2443446%8%38%
2618
June1st to 15thDay
19%5%24324448%39%
2520
16th to endDay
9%3245%35%5%5%8%46%
2520
July1st to 15thDay
8%4345%35%5%6%9%43%
2520
16th to endDay
10%5%33435%5%6%9%42%
2654
August1st to 15thDay
9%5%2433446%8%49%
2258
16th to endDay
11%42442345%7%49%
2100
September1st to 15thDay
11%5%244135%6%7%47%
1966
16th to endDay
14%6%24423347%46%
1815
October1st to 15thDay
17%6%24423345%44%
1733
16th to endDay
17%42333346%8%43%
1650
November1st to 15thDay
18%6%24333336%45%
1581
16th to endDay
14%5%245%2445%8%41%
1614
December1st to 15thDay
16%7%24425%5%6%5%39%
1440
16th to endDay
21%7%245%2335%6%36%
1536
January1st to 15thNight
18%6%2442435%8%39%
2506
16th to endNight
18%7%23324446%41%
2622
February1st to 15thNight
14%8%35%4245%5%6%38%
2181
16th to endNight
17%5%23423447%44%
1893
March1st to 15thNight
18%6%24423347%42%
2160
16th to endNight
17%7%33313346%45%
1998
April1st to 15thNight
18%7%24434447%39%
1796
16th to endNight
18%6%35%43335%6%40%
1761
May1st to 15thNight
18%8%25%5%35%45%6%34%
1620
16th to endNight
20%6%25%42445%8%36%
1502
June1st to 15thNight
21%435%423347%39%
1440
16th to endNight
8%425%6%25%5%6%10%42%
1440
July1st to 15thNight
10%5%35%435%5%7%10%38%
1440
16th to endNight
9%6%35%426%6%6%9%39%
1514
August1st to 15thNight
8%424435%6%7%7%45%
1604
16th to endNight
12%425%5%3435%9%44%
1750
September1st to 15thNight
14%4145%345%5%6%44%
1664
16th to endNight
14%5%25%424245%48%
1815
October1st to 15thNight
18%6%35%423335%43%
1895
16th to endNight
18%5%25%434345%42%
2222
November1st to 15thNight
17%6%2432323447%
2277
16th to endNight
17%6%25%42345%7%39%
2344
December1st to 15thNight
21%6%2442345%8%35%
2520
16th to endNight
20%6%25%43345%7%37%
2688

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
44%6%14%22%10%2
1433
16th to endDay
41%5%16%23%11%2
1601
February1st to 15thDay
43%6%14%21%13%
1675
16th to endDay
42%5%11%26%12%1
1580
March1st to 15thDay
43%5%15%23%10%1
1800
16th to endDay
41%5%11%22%16%2
2223
April1st to 15thDay
41%411%23%15%3
2152
16th to endDay
39%410%22%19%2
2199
May1st to 15thDay
45%5%10%20%15%1
2335
16th to endDay
41%8%15%20%12%1
2622
June1st to 15thDay
42%7%14%22%12%
2520
16th to endDay
34%7%16%25%14%1
2520
July1st to 15thDay
34%8%14%23%17%1
2371
16th to endDay
34%8%14%26%12%2
2487
August1st to 15thDay
31%7%16%26%15%1
2244
16th to endDay
33%7%11%25%19%2
2100
September1st to 15thDay
34%6%14%21%20%1
1966
16th to endDay
38%5%11%22%21%1
1815
October1st to 15thDay
41%5%11%22%17%1
1733
16th to endDay
38%5%14%24%16%1
1650
November1st to 15thDay
42%5%12%21%17%1
1581
16th to endDay
41%6%15%23%11%2
1614
December1st to 15thDay
44%6%16%17%13%
1440
16th to endDay
49%416%18%11%
1536
January1st to 15thNight
44%414%21%12%2
2506
16th to endNight
44%413%23%13%1
2622
February1st to 15thNight
44%5%13%22%11%1
2189
16th to endNight
39%5%11%24%17%2
1893
March1st to 15thNight
43%414%20%13%3
2160
16th to endNight
41%39%22%17%4
1999
April1st to 15thNight
43%412%20%15%3
1796
16th to endNight
44%5%9%16%21%3
1761
May1st to 15thNight
48%6%10%17%14%3
1620
16th to endNight
44%7%14%17%13%1
1504
June1st to 15thNight
46%6%11%18%16%1
1440
16th to endNight
36%7%14%25%14%1
1440
July1st to 15thNight
39%9%13%22%13%1
1360
16th to endNight
37%8%14%26%11%2
1418
August1st to 15thNight
33%8%14%25%16%1
1594
16th to endNight
36%7%12%24%17%1
1750
September1st to 15thNight
37%7%11%23%19%
1664
16th to endNight
38%48%21%24%1
1815
October1st to 15thNight
43%410%22%16%2
1895
16th to endNight
43%412%22%15%1
2222
November1st to 15thNight
42%411%20%18%3
2277
16th to endNight
44%5%13%24%10%2
2344
December1st to 15thNight
48%6%16%16%10%
2520
16th to endNight
46%6%15%20%10%1
2688

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
13%21%31%26%6%
60
16th to endDay
20%8%37%32%2
75
February1st to 15thDay
20%21%35%21%1
188
16th to endDay
14%20%33%24%7%
239
March1st to 15thDay
22%17%31%22%5%
270
16th to endDay
19%19%29%23%5%1
288
April1st to 15thDay
19%17%23%28%9%
270
16th to endDay
20%13%20%32%10%1
270
May1st to 15thDay
29%13%22%23%9%1
288
16th to endDay
21%11%13%31%21%
331
June1st to 15thDay
19%11%18%26%21%3
315
16th to endDay
11%9%15%42%18%1
315
July1st to 15thDay
11%6%11%40%27%2
305
16th to endDay
11%10%10%32%31%3
326
August1st to 15thDay
11%6%10%33%31%5%
297
16th to endDay
13%6%6%30%31%11%
268
September1st to 15thDay
15%6%18%25%24%9%
255
16th to endDay
18%7%13%28%22%9%
254
October1st to 15thDay
23%9%15%24%22%5%
255
16th to endDay
16%15%30%25%12%
252
November1st to 15thDay
20%18%21%20%15%2
235
16th to endDay
14%25%26%24%7%2
234
December1st to 15thDay
16%13%33%28%6%1
60
16th to endDay
37%7%29%23%1
64
January1st to 15thNight
15%31%29%19%3
720
16th to endNight
20%28%32%17%1
768
February1st to 15thNight
15%27%36%18%1
704
16th to endNight
16%27%30%20%4
631
March1st to 15thNight
20%24%28%20%5%
720
16th to endNight
18%22%30%20%7%1
768
April1st to 15thNight
18%21%25%26%6%
718
16th to endNight
18%19%22%28%10%1
681
May1st to 15thNight
20%19%20%26%10%2
540
16th to endNight
19%19%11%30%17%2
382
June1st to 15thNight
19%17%14%28%19%1
360
16th to endNight
8%17%11%41%20%1
360
July1st to 15thNight
10%12%12%35%25%2
340
16th to endNight
10%17%10%33%23%4
376
August1st to 15thNight
10%10%11%38%26%1
545
16th to endNight
14%9%6%29%32%7%
700
September1st to 15thNight
14%11%15%31%22%5%
660
16th to endNight
16%11%14%27%22%7%
657
October1st to 15thNight
20%15%20%24%17%1
660
16th to endNight
20%18%27%24%9%
704
November1st to 15thNight
17%23%26%17%13%1
700
16th to endNight
16%26%27%20%8%
720
December1st to 15thNight
22%28%24%16%6%1
720
16th to endNight
22%28%30%16%1
768
Page generated at 2017-08-13 14:16:35. Version ac04

Copyright 2017 A. Danko


Robert Moses State Park Clear Sky Chart | Charts Home