Queens
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Queens clear sky chart from 2005-11-05 to 2017-09-21.

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
27%
15177
12%
46683
6%
15134
33%
15134
14%
34605

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
16%
745
8%
2473
3%
741
23%
741
8%
1934
January16th to endNight
15%
768
9%
2496
2%
768
24%
768
8%
1972
February1st to 15thNight
13%
702
7%
2286
1%
701
20%
701
7%
1829
February16th to endNight
18%
631
9%
2020
3%
631
26%
631
11%
1512
March1st to 15thNight
19%
720
14%
1980
5%
720
26%
720
14%
1507
March16th to endNight
21%
768
15%
2112
6%
768
30%
768
16%
1534
April1st to 15thNight
20%
568
14%
1822
6%
568
29%
568
14%
1311
April16th to endNight
30%
540
15%
1620
7%
540
36%
540
17%
1155
May1st to 15thNight
27%
540
11%
1573
6%
540
31%
540
13%
1215
May16th to endNight
31%
561
11%
1496
6%
560
35%
560
17%
1119
June1st to 15thNight
30%
540
7%
1440
4%
540
32%
540
15%
1144
June16th to endNight
33%
370
7%
1270
4%
370
37%
370
12%
941
July1st to 15thNight
46%
423
10%
1273
9%
423
48%
423
17%
907
July16th to endNight
41%
565
8%
1522
6%
532
45%
532
15%
1170
August1st to 15thNight
46%
539
14%
1608
10%
535
49%
535
20%
1105
August16th to endNight
49%
573
18%
1773
12%
573
54%
573
23%
1148
September1st to 15thNight
46%
558
18%
1818
15%
558
52%
558
22%
1177
September16th to endNight
42%
681
21%
1896
15%
681
48%
681
24%
1270
October1st to 15thNight
31%
660
18%
1980
9%
660
39%
660
21%
1346
October16th to endNight
23%
704
15%
2112
6%
704
31%
704
18%
1493
November1st to 15thNight
32%
721
12%
2385
8%
721
38%
721
14%
1733
November16th to endNight
18%
750
9%
2520
4%
750
25%
750
11%
1914
December1st to 15thNight
16%
750
9%
2520
1%
750
24%
750
9%
1971
December16th to endNight
12%
800
8%
2688
1%
800
19%
800
6%
2198

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
20%8%36%5%3445%7%30%
48167
Night
20%8%35%5%3445%7%31%
46862
TransparencyDay
52%7%11%17%9%1
47864
Night
54%6%11%17%8%
46683
SeeingDay
23%16%24%24%9%1
7432
Night
22%21%23%23%8%1
15179

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
16%10%5%8%6%46%5%6%8%21%
1462
16th to endDay
18%10%46%5%445%7%8%24%
1728
February1st to 15thDay
17%10%5%7%5%46%6%6%6%21%
1575
16th to endDay
14%9%6%7%6%46%5%5%7%26%
1452
March1st to 15thDay
21%11%47%5%24346%28%
1969
16th to endDay
16%10%5%6%6%34445%32%
2112
April1st to 15thDay
21%11%46%5%33345%29%
2124
16th to endDay
23%6%46%424346%34%
2340
May1st to 15thDay
25%9%37%5%24347%27%
2377
16th to endDay
23%9%35%42335%7%31%
2618
June1st to 15thDay
27%9%35%5%24346%26%
2520
16th to endDay
21%7%27%5%245%5%7%29%
2697
July1st to 15thDay
18%6%35%5%2445%10%33%
2595
16th to endDay
19%7%46%5%345%6%7%28%
2538
August1st to 15thDay
17%6%25%5%245%6%8%34%
2340
16th to endDay
13%5%2443445%8%42%
2429
September1st to 15thDay
16%6%2441345%6%43%
2139
16th to endDay
16%6%25%5%23446%42%
1857
October1st to 15thDay
23%5%14324346%39%
1650
16th to endDay
23%6%26%5%45%5%5%6%30%
1760
November1st to 15thDay
21%9%36%5%24446%30%
1469
16th to endDay
23%8%35%6%3445%7%26%
1440
December1st to 15thDay
23%8%37%6%35%5%7%7%20%
1440
16th to endDay
25%9%38%6%345%6%6%20%
1536
January1st to 15thNight
16%9%45%7%45%5%6%8%25%
2473
16th to endNight
18%10%48%5%35%6%6%7%23%
2496
February1st to 15thNight
18%10%37%7%46%6%5%7%22%
2285
16th to endNight
14%8%47%6%46%5%5%7%29%
2020
March1st to 15thNight
21%10%35%5%34446%30%
1968
16th to endNight
18%9%45%6%24345%34%
2112
April1st to 15thNight
25%9%25%5%3334431%
1822
16th to endNight
24%8%2442445%6%32%
1620
May1st to 15thNight
26%9%46%433346%27%
1573
16th to endNight
22%7%36%5%23446%32%
1494
June1st to 15thNight
29%9%35%433346%25%
1440
16th to endNight
24%7%35%6%34346%30%
1270
July1st to 15thNight
18%6%35%4245%6%8%34%
1350
16th to endNight
20%8%45%5%3446%7%30%
1627
August1st to 15thNight
17%6%25%5%2335%6%40%
1620
16th to endNight
15%5%25%433348%43%
1773
September1st to 15thNight
16%6%243345%47%42%
1818
16th to endNight
19%5%24423336%44%
1896
October1st to 15thNight
22%5%24423346%39%
1980
16th to endNight
22%5%2433345%7%36%
2112
November1st to 15thNight
21%7%25%425%45%7%32%
2385
16th to endNight
22%7%35%5%35%45%7%30%
2520
December1st to 15thNight
23%8%37%5%35%46%8%24%
2520
16th to endNight
25%9%45%5%25%5%6%6%22%
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
59%9%13%12%4
1463
16th to endDay
57%8%11%16%5%
1728
February1st to 15thDay
61%7%13%12%3
1578
16th to endDay
53%8%13%17%5%1
1452
March1st to 15thDay
56%5%10%17%9%1
1980
16th to endDay
48%5%12%20%11%2
2112
April1st to 15thDay
52%5%9%17%13%1
2124
16th to endDay
50%413%18%11%1
2340
May1st to 15thDay
57%6%11%15%8%1
2377
16th to endDay
52%7%12%19%7%
2622
June1st to 15thDay
59%6%10%15%7%1
2520
16th to endDay
55%8%9%14%10%1
2697
July1st to 15thDay
50%7%13%17%9%1
2444
16th to endDay
56%8%10%17%5%1
2380
August1st to 15thDay
47%7%12%20%10%1
2327
16th to endDay
39%8%14%24%13%
2429
September1st to 15thDay
41%5%11%23%16%1
2139
16th to endDay
41%6%8%25%16%
1857
October1st to 15thDay
44%6%10%23%13%1
1650
16th to endDay
53%6%12%17%9%
1760
November1st to 15thDay
54%6%12%17%7%1
1469
16th to endDay
58%7%12%15%6%
1440
December1st to 15thDay
62%9%12%11%4
1440
16th to endDay
65%8%9%11%5%
1536
January1st to 15thNight
59%9%13%13%4
2473
16th to endNight
60%8%11%14%4
2496
February1st to 15thNight
61%9%11%12%5%
2286
16th to endNight
54%8%15%14%6%
2020
March1st to 15thNight
56%5%10%17%9%1
1980
16th to endNight
51%411%18%12%1
2112
April1st to 15thNight
55%49%16%12%2
1822
16th to endNight
52%410%19%11%2
1620
May1st to 15thNight
60%47%18%8%
1573
16th to endNight
53%6%12%18%8%
1496
June1st to 15thNight
61%410%17%5%
1440
16th to endNight
58%5%11%12%11%
1270
July1st to 15thNight
48%8%12%19%9%1
1273
16th to endNight
55%9%10%18%5%1
1522
August1st to 15thNight
46%6%11%23%10%
1608
16th to endNight
40%7%14%23%14%
1773
September1st to 15thNight
43%5%9%25%13%2
1818
16th to endNight
43%5%7%26%17%
1896
October1st to 15thNight
46%5%11%23%10%2
1980
16th to endNight
48%7%11%21%11%
2112
November1st to 15thNight
52%7%13%18%7%
2385
16th to endNight
56%9%13%14%6%
2520
December1st to 15thNight
61%7%12%14%3
2520
16th to endNight
66%7%9%11%4
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
17%27%33%18%3
240
16th to endDay
21%23%35%15%2
256
February1st to 15thDay
22%27%26%22%1
236
16th to endDay
15%22%35%22%3
218
March1st to 15thDay
24%22%30%17%5%
270
16th to endDay
23%22%26%19%5%1
288
April1st to 15thDay
27%16%30%19%6%
270
16th to endDay
18%15%28%26%9%
270
May1st to 15thDay
25%16%25%23%7%1
333
16th to endDay
27%16%22%24%7%
519
June1st to 15thDay
26%14%18%31%8%
495
16th to endDay
23%15%18%28%11%1
495
July1st to 15thDay
25%10%14%34%13%1
475
16th to endDay
23%13%15%30%16%1
399
August1st to 15thDay
22%8%16%30%19%1
313
16th to endDay
16%7%22%26%22%4
332
September1st to 15thDay
19%7%23%33%13%2
315
16th to endDay
20%9%23%26%16%3
272
October1st to 15thDay
24%12%22%25%11%2
225
16th to endDay
23%17%31%18%8%
240
November1st to 15thDay
20%20%22%25%10%
235
16th to endDay
24%25%26%17%5%
240
December1st to 15thDay
30%22%28%15%2
240
16th to endDay
28%24%32%13%1
256
January1st to 15thNight
18%28%30%18%3
745
16th to endNight
20%28%29%17%3
768
February1st to 15thNight
25%27%29%16%1
704
16th to endNight
17%27%31%18%5%
631
March1st to 15thNight
24%24%28%19%3
720
16th to endNight
20%26%26%20%5%
768
April1st to 15thNight
26%20%25%20%6%
568
16th to endNight
21%19%22%26%8%1
540
May1st to 15thNight
27%19%18%23%7%2
540
16th to endNight
24%20%16%26%9%2
561
June1st to 15thNight
26%18%16%27%9%
540
16th to endNight
25%18%14%26%14%
370
July1st to 15thNight
19%13%12%37%16%
423
16th to endNight
20%18%12%34%13%
565
August1st to 15thNight
19%10%12%32%22%2
539
16th to endNight
16%9%15%35%19%3
573
September1st to 15thNight
19%11%16%36%12%3
558
16th to endNight
21%11%18%28%17%3
681
October1st to 15thNight
23%14%26%25%8%1
660
16th to endNight
22%17%31%22%4
704
November1st to 15thNight
21%20%22%24%10%1
721
16th to endNight
22%26%26%16%6%
750
December1st to 15thNight
25%26%26%16%4
750
16th to endNight
29%27%27%13%2
800
Page generated at 2017-09-22 08:35:38. Version ac04

Copyright 2017 A. Danko


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