Upstate Stars Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Upstate Stars Observatory clear sky chart from 2005-11-05 to 2018-10-27.

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%
16340
15%
51251
8%
16309
37%
16309
17%
35098

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%
780
12%
2716
5%
776
25%
776
11%
1890
January16th to endNight
13%
832
13%
2805
3%
832
25%
832
11%
1942
February1st to 15thNight
7%
764
10%
2465
1%
761
18%
761
8%
1824
February16th to endNight
15%
683
16%
2049
6%
683
28%
683
12%
1446
March1st to 15thNight
15%
780
13%
2298
4%
780
26%
780
13%
1638
March16th to endNight
22%
832
19%
2183
7%
832
32%
832
18%
1503
April1st to 15thNight
18%
778
14%
1946
3%
778
24%
778
16%
1460
April16th to endNight
27%
768
16%
1924
5%
768
33%
768
21%
1357
May1st to 15thNight
32%
471
17%
1641
11%
471
41%
471
16%
1108
May16th to endNight
39%
406
14%
1625
12%
406
46%
406
17%
1042
June1st to 15thNight
39%
390
14%
1560
10%
390
50%
390
16%
1010
June16th to endNight
51%
390
12%
1560
11%
390
59%
390
24%
901
July1st to 15thNight
54%
370
14%
1480
17%
370
57%
370
23%
868
July16th to endNight
55%
408
15%
1546
18%
386
60%
386
22%
911
August1st to 15thNight
53%
555
14%
1696
10%
553
57%
553
26%
1093
August16th to endNight
56%
828
17%
2070
9%
828
58%
828
32%
1382
September1st to 15thNight
42%
780
18%
1950
9%
780
45%
780
28%
1338
September16th to endNight
49%
777
24%
2109
18%
777
53%
777
30%
1349
October1st to 15thNight
36%
780
18%
2327
13%
780
43%
780
20%
1587
October16th to endNight
22%
816
15%
2530
8%
816
33%
816
15%
1782
November1st to 15thNight
29%
760
17%
2472
10%
760
39%
760
17%
1653
November16th to endNight
24%
780
17%
2657
9%
780
34%
780
15%
1792
December1st to 15thNight
16%
780
8%
2730
3%
780
23%
780
8%
2055
December16th to endNight
13%
832
9%
2912
2%
832
22%
832
7%
2167

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%8%36%6%35%45%6%30%
52309
Night
17%7%36%5%3445%6%34%
51420
Cloud CoverDay
17%7%36%6%35%45%7%32%
52318
Night
17%7%35%5%2445%7%36%
51426
TransparencyDay
51%6%12%18%10%1
51996
Night
47%6%14%19%11%1
51251
SeeingDay
25%15%25%18%11%4
7097
Night
23%17%25%22%9%1
16341

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%9%48%8%45%5%5%5%24%
1552
16th to endDay
13%10%5%9%7%45%5%5%7%24%
1768
February1st to 15thDay
15%12%6%9%8%45%447%21%
1726
16th to endDay
17%9%48%8%3435%6%28%
1710
March1st to 15thDay
16%12%5%8%7%35%446%26%
1979
16th to endDay
16%10%47%6%24346%32%
2392
April1st to 15thDay
20%11%46%5%24335%32%
2332
16th to endDay
17%9%35%5%34345%36%
2311
May1st to 15thDay
22%7%26%6%2445%5%30%
2650
16th to endDay
19%7%36%5%25%5%46%32%
2842
June1st to 15thDay
21%5%36%5%46%46%8%27%
2730
16th to endDay
17%7%36%6%35%5%5%8%29%
2730
July1st to 15thDay
13%6%35%5%46%6%5%8%33%
2730
16th to endDay
13%5%35%5%46%5%6%8%34%
2878
August1st to 15thDay
18%6%26%6%36%5%6%8%29%
2492
16th to endDay
14%5%25%5%35%5%7%8%35%
2484
September1st to 15thDay
19%6%35%6%45%45%7%32%
2340
16th to endDay
16%5%245%24446%42%
2181
October1st to 15thDay
22%9%26%434446%31%
1960
16th to endDay
20%11%36%5%34446%27%
1951
November1st to 15thDay
17%9%36%5%24345%35%
1716
16th to endDay
19%9%45%6%34345%33%
1631
December1st to 15thDay
19%12%5%10%6%33446%23%
1560
16th to endDay
19%12%6%9%7%45%5%6%5%18%
1664
January1st to 15thNight
17%9%48%6%45%6%6%6%25%
2716
16th to endNight
13%10%5%7%7%45%5%6%6%27%
2805
February1st to 15thNight
15%11%5%8%7%46%46%6%24%
2463
16th to endNight
15%9%38%7%35%5%5%6%28%
2049
March1st to 15thNight
17%9%37%6%35%46%7%30%
2285
16th to endNight
15%7%47%6%2445%7%36%
2183
April1st to 15thNight
18%11%37%425%446%31%
1946
16th to endNight
18%7%45%423346%38%
1924
May1st to 15thNight
19%6%36%5%24447%35%
1641
16th to endNight
16%6%35%5%3447%7%36%
1623
June1st to 15thNight
18%5%35%5%3435%7%37%
1560
16th to endNight
13%4135%2446%9%43%
1560
July1st to 15thNight
13%425%425%5%6%8%42%
1560
16th to endNight
12%5%24435%45%8%42%
1642
August1st to 15thNight
14%5%245%245%6%7%40%
1706
16th to endNight
15%42442445%7%43%
2070
September1st to 15thNight
19%425%424346%42%
1950
16th to endNight
15%4145%33347%46%
2109
October1st to 15thNight
21%6%25%42424440%
2327
16th to endNight
20%8%36%5%24445%32%
2530
November1st to 15thNight
16%7%35%5%34446%37%
2472
16th to endNight
17%8%36%5%3445%6%33%
2657
December1st to 15thNight
21%11%5%8%6%34446%21%
2730
16th to endNight
19%10%48%7%36%5%5%7%21%
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
16%8%36%7%45%6%5%8%28%
1552
16th to endDay
12%9%5%8%7%36%45%7%27%
1768
February1st to 15thDay
16%11%6%8%7%345%5%7%23%
1726
16th to endDay
18%8%27%7%3435%6%30%
1710
March1st to 15thDay
16%11%47%7%3435%6%27%
1989
16th to endDay
16%9%46%5%34346%34%
2391
April1st to 15thDay
20%9%45%6%23345%33%
2332
16th to endDay
17%8%25%5%34346%37%
2311
May1st to 15thDay
22%7%35%5%2445%6%31%
2650
16th to endDay
20%6%25%5%35%5%5%7%32%
2842
June1st to 15thDay
21%5%36%5%36%46%8%28%
2730
16th to endDay
16%7%37%6%35%6%5%8%31%
2730
July1st to 15thDay
13%6%25%6%36%46%8%34%
2730
16th to endDay
13%5%35%5%45%5%7%8%34%
2878
August1st to 15thDay
16%7%25%5%35%6%6%9%30%
2492
16th to endDay
14%5%245%45%5%6%8%37%
2484
September1st to 15thDay
18%6%25%5%35%45%8%33%
2340
16th to endDay
16%5%24424446%43%
2181
October1st to 15thDay
21%9%35%5%24446%33%
1960
16th to endDay
20%8%27%5%3445%7%29%
1951
November1st to 15thDay
17%9%346%2335%6%36%
1716
16th to endDay
19%8%26%5%33446%35%
1631
December1st to 15thDay
20%10%38%6%3445%6%26%
1560
16th to endDay
19%11%48%6%35%46%7%21%
1664
January1st to 15thNight
17%7%36%6%35%5%7%8%28%
2716
16th to endNight
13%9%46%5%45%5%6%8%31%
2805
February1st to 15thNight
15%10%37%6%45%5%5%6%28%
2456
16th to endNight
15%8%36%6%25%5%6%7%32%
2049
March1st to 15thNight
18%8%35%43445%8%32%
2298
16th to endNight
16%6%35%42435%7%39%
2183
April1st to 15thNight
18%9%35%5%34445%33%
1946
16th to endNight
19%6%34423446%39%
1924
May1st to 15thNight
19%7%25%42445%6%36%
1641
16th to endNight
16%6%25%42446%8%37%
1623
June1st to 15thNight
19%425%42435%8%38%
1560
16th to endNight
13%4133245%6%9%45%
1560
July1st to 15thNight
13%4245%2346%9%44%
1560
16th to endNight
12%5%2442446%9%42%
1642
August1st to 15thNight
14%5%144345%6%7%41%
1706
16th to endNight
15%4245%2445%7%44%
2070
September1st to 15thNight
17%5%2442445%6%43%
1950
16th to endNight
15%424423347%46%
2109
October1st to 15thNight
22%5%24424345%40%
2327
16th to endNight
20%7%35%434446%35%
2530
November1st to 15thNight
17%7%25%42445%7%38%
2472
16th to endNight
18%6%35%5%245%5%7%34%
2657
December1st to 15thNight
22%9%47%5%245%5%6%24%
2730
16th to endNight
19%9%46%5%35%5%6%8%25%
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
54%5%13%17%6%2
1553
16th to endDay
54%5%16%15%7%
1768
February1st to 15thDay
60%5%11%13%8%
1728
16th to endDay
54%412%18%9%
1710
March1st to 15thDay
56%5%14%15%7%1
1989
16th to endDay
51%5%9%16%14%2
2392
April1st to 15thDay
54%49%19%9%2
2332
16th to endDay
48%48%20%15%3
2311
May1st to 15thDay
53%6%7%20%10%1
2650
16th to endDay
50%8%11%18%10%
2846
June1st to 15thDay
53%7%12%17%9%
2730
16th to endDay
50%6%13%19%9%
2730
July1st to 15thDay
45%8%12%19%13%1
2581
16th to endDay
43%8%14%19%12%
2711
August1st to 15thDay
48%8%13%20%8%
2478
16th to endDay
42%7%13%22%13%
2484
September1st to 15thDay
48%6%12%18%13%
2340
16th to endDay
41%5%9%23%18%2
2181
October1st to 15thDay
52%6%9%18%11%1
1960
16th to endDay
54%5%14%16%8%
1951
November1st to 15thDay
47%5%16%15%12%2
1716
16th to endDay
51%413%19%9%1
1631
December1st to 15thDay
59%6%15%12%5%1
1560
16th to endDay
61%6%14%11%5%
1664
January1st to 15thNight
51%6%16%16%7%1
2716
16th to endNight
50%6%17%16%8%
2805
February1st to 15thNight
55%6%14%13%8%
2465
16th to endNight
51%414%18%9%1
2049
March1st to 15thNight
49%6%16%18%8%1
2298
16th to endNight
44%5%13%19%14%2
2183
April1st to 15thNight
52%6%9%19%11%1
1946
16th to endNight
45%5%9%19%18%1
1924
May1st to 15thNight
47%6%10%19%14%1
1641
16th to endNight
44%7%14%22%10%1
1625
June1st to 15thNight
45%7%12%24%10%
1560
16th to endNight
35%8%18%23%13%
1560
July1st to 15thNight
37%6%14%24%14%1
1480
16th to endNight
37%7%16%23%13%1
1546
August1st to 15thNight
38%7%16%25%10%1
1696
16th to endNight
37%6%13%26%14%
2070
September1st to 15thNight
41%6%13%23%14%
1950
16th to endNight
37%49%24%21%1
2109
October1st to 15thNight
45%6%11%19%15%1
2327
16th to endNight
49%6%13%20%9%
2530
November1st to 15thNight
45%6%12%18%13%2
2472
16th to endNight
49%5%15%19%9%1
2657
December1st to 15thNight
58%6%16%12%5%
2730
16th to endNight
57%6%16%14%5%
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
36%28%22%8%21
90
16th to endDay
25%29%35%7%2
120
February1st to 15thDay
34%38%22%31
152
16th to endDay
31%24%27%13%2
291
March1st to 15thDay
30%24%26%16%2
330
16th to endDay
26%27%24%13%5%2
352
April1st to 15thDay
33%20%25%11%7%1
330
16th to endDay
24%17%31%13%8%5%
319
May1st to 15thDay
35%17%22%14%6%4
348
16th to endDay
23%11%28%21%11%3
395
June1st to 15thDay
25%12%27%21%11%2
375
16th to endDay
22%11%28%24%10%1
375
July1st to 15thDay
17%7%24%27%17%4
365
16th to endDay
17%6%28%26%16%4
390
August1st to 15thDay
21%9%22%19%18%8%
358
16th to endDay
16%6%21%24%20%10%
396
September1st to 15thDay
23%10%19%18%17%10%
375
16th to endDay
18%5%25%19%17%13%
374
October1st to 15thDay
28%8%21%21%15%4
375
16th to endDay
30%20%23%17%7%
360
November1st to 15thDay
25%16%24%20%11%2
280
16th to endDay
25%26%24%18%41
161
December1st to 15thDay
33%24%24%10%6%1
90
16th to endDay
39%30%28%2
96
January1st to 15thNight
27%24%26%17%3
780
16th to endNight
23%24%32%16%1
832
February1st to 15thNight
26%26%33%12%1
764
16th to endNight
29%24%27%15%2
683
March1st to 15thNight
28%24%28%15%2
780
16th to endNight
22%25%26%18%6%
832
April1st to 15thNight
27%20%29%18%3
778
16th to endNight
25%19%25%20%9%
768
May1st to 15thNight
26%11%23%28%8%
471
16th to endNight
18%10%24%31%14%1
407
June1st to 15thNight
21%8%24%30%13%
390
16th to endNight
15%323%41%15%
390
July1st to 15thNight
15%420%36%21%1
370
16th to endNight
15%317%39%20%2
408
August1st to 15thNight
15%322%34%21%2
555
16th to endNight
17%315%32%26%3
828
September1st to 15thNight
21%6%23%26%19%3
780
16th to endNight
17%8%18%26%21%7%
777
October1st to 15thNight
25%11%20%24%15%1
780
16th to endNight
26%18%27%21%5%
816
November1st to 15thNight
21%19%24%23%10%1
760
16th to endNight
23%21%26%20%7%1
780
December1st to 15thNight
30%24%24%16%4
780
16th to endNight
29%27%25%16%2
832
Page generated at 2018-10-28 08:41:02. Version ac04

Copyright 2018 A. Danko


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