Kingston
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kingston clear sky chart from 2005-11-05 to 2018-02-22.

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
30%
15377
14%
48936
8%
15346
36%
15346
17%
34812

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%
780
8%
2716
4%
776
20%
776
7%
2163
January16th to endNight
18%
832
10%
2805
5%
832
24%
832
9%
2179
February1st to 15thNight
13%
764
9%
2482
3%
761
21%
761
9%
1978
February16th to endNight
21%
659
13%
2044
5%
659
30%
659
14%
1533
March1st to 15thNight
21%
720
14%
2070
7%
720
29%
720
16%
1534
March16th to endNight
30%
768
19%
2054
9%
768
37%
768
24%
1423
April1st to 15thNight
24%
718
15%
1796
4%
718
29%
718
21%
1307
April16th to endNight
32%
675
17%
1755
7%
675
37%
675
24%
1218
May1st to 15thNight
40%
369
17%
1449
15%
369
48%
369
18%
947
May16th to endNight
43%
374
15%
1497
15%
374
51%
374
20%
907
June1st to 15thNight
41%
360
12%
1440
13%
360
48%
360
17%
929
June16th to endNight
46%
360
10%
1440
13%
360
51%
360
20%
887
July1st to 15thNight
53%
340
15%
1360
20%
340
59%
340
25%
774
July16th to endNight
57%
376
15%
1418
16%
354
61%
354
27%
796
August1st to 15thNight
51%
500
14%
1571
10%
498
55%
498
26%
985
August16th to endNight
53%
705
23%
1851
11%
705
58%
705
37%
1141
September1st to 15thNight
51%
720
18%
1800
9%
720
55%
720
34%
1172
September16th to endNight
49%
717
24%
1965
17%
717
54%
717
32%
1240
October1st to 15thNight
33%
720
16%
2160
11%
720
41%
720
18%
1529
October16th to endNight
21%
768
10%
2364
5%
768
28%
768
12%
1807
November1st to 15thNight
28%
760
17%
2527
12%
760
36%
760
17%
1744
November16th to endNight
19%
780
12%
2730
7%
780
26%
780
9%
2091
December1st to 15thNight
16%
780
7%
2730
2%
780
21%
780
7%
2172
December16th to endNight
11%
832
8%
2912
2%
832
19%
832
8%
2356

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%7%35%5%3445%7%35%
49322
Night
18%9%36%5%34446%33%
49106
Cloud CoverDay
17%8%35%5%2445%7%35%
49332
Night
18%9%36%5%34446%33%
49111
TransparencyDay
48%7%12%20%10%1
49010
Night
51%6%11%19%10%1
48936
SeeingDay
20%12%29%21%11%4
5924
Night
23%12%28%23%10%1
15378

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
23%12%37%5%25%445%25%
1552
16th to endDay
14%15%5%9%7%45%5%45%21%
1768
February1st to 15thDay
17%12%6%11%8%34445%21%
1710
16th to endDay
22%12%45%6%2436%6%25%
1574
March1st to 15thDay
17%11%48%8%3444426%
1879
16th to endDay
17%8%35%5%2344440%
2169
April1st to 15thDay
21%7%345%33446%34%
2152
16th to endDay
18%6%25%5%2445%6%39%
2216
May1st to 15thDay
17%6%35%6%245%5%6%35%
2502
16th to endDay
13%5%245%2445%9%40%
2618
June1st to 15thDay
19%5%35%5%3446%7%35%
2520
16th to endDay
14%5%24435%45%9%40%
2520
July1st to 15thDay
10%4244345%6%8%45%
2520
16th to endDay
11%4245%35%5%6%9%40%
2654
August1st to 15thDay
10%4245%35%6%6%9%41%
2377
16th to endDay
12%41332346%10%46%
2339
September1st to 15thDay
15%5%2432345%7%43%
2160
16th to endDay
14%5%2443335%7%46%
1992
October1st to 15thDay
22%5%245%33446%37%
1800
16th to endDay
26%7%36%433446%27%
1859
November1st to 15thDay
16%6%35%7%35%5%47%33%
1657
16th to endDay
24%9%36%5%35%45%5%25%
1560
December1st to 15thDay
22%15%47%5%35%5%35%20%
1560
16th to endDay
24%15%5%6%6%24436%19%
1664
January1st to 15thNight
21%14%48%6%3444421%
2716
16th to endNight
16%14%49%6%34446%24%
2805
February1st to 15thNight
17%14%5%9%7%34435%22%
2480
16th to endNight
19%10%48%6%34336%29%
2044
March1st to 15thNight
21%11%45%5%2433432%
2058
16th to endNight
18%8%36%42333441%
2054
April1st to 15thNight
23%7%35%32435%6%35%
1796
16th to endNight
17%6%24424446%40%
1755
May1st to 15thNight
20%6%2443445%6%37%
1449
16th to endNight
12%425%5%35%5%6%7%41%
1495
June1st to 15thNight
18%5%35%5%3335%9%36%
1440
16th to endNight
14%425%5%336%5%8%39%
1440
July1st to 15thNight
8%4235%35%5%5%8%47%
1440
16th to endNight
8%4244235%7%9%46%
1514
August1st to 15thNight
11%425%43446%9%43%
1581
16th to endNight
9%41342446%7%50%
1851
September1st to 15thNight
14%5%25%324347%48%
1800
16th to endNight
15%33332335%7%47%
1965
October1st to 15thNight
19%7%346%33346%36%
2160
16th to endNight
24%8%37%5%345%45%28%
2364
November1st to 15thNight
21%7%25%424445%36%
2527
16th to endNight
22%10%35%5%2445%6%27%
2730
December1st to 15thNight
22%15%5%7%5%33446%22%
2730
16th to endNight
24%15%46%5%3445%5%20%
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
23%13%47%6%24445%22%
1552
16th to endDay
15%15%5%10%7%35%5%5%5%20%
1768
February1st to 15thDay
17%13%6%10%8%35%44421%
1710
16th to endDay
22%12%45%5%35%346%26%
1574
March1st to 15thDay
18%11%49%7%3444426%
1890
16th to endDay
17%9%35%42334440%
2168
April1st to 15thDay
22%7%34424436%35%
2152
16th to endDay
18%5%25%5%34445%39%
2216
May1st to 15thDay
16%6%35%5%245%5%7%36%
2502
16th to endDay
13%5%25%43445%10%40%
2618
June1st to 15thDay
19%5%25%5%2446%7%35%
2520
16th to endDay
14%424435%5%5%8%41%
2520
July1st to 15thDay
10%42443445%9%45%
2520
16th to endDay
11%4145%25%6%6%9%41%
2654
August1st to 15thDay
11%4244345%6%9%42%
2377
16th to endDay
11%41332445%9%47%
2339
September1st to 15thDay
16%42443435%6%44%
2160
16th to endDay
14%5%34423347%46%
1992
October1st to 15thDay
21%7%25%5%2335%6%36%
1800
16th to endDay
27%7%35%5%34446%27%
1859
November1st to 15thDay
16%7%36%6%35%5%46%33%
1657
16th to endDay
23%11%47%5%24446%24%
1560
December1st to 15thDay
23%16%47%6%445%45%18%
1560
16th to endDay
25%16%5%7%5%35%345%17%
1664
January1st to 15thNight
21%15%5%9%5%3434320%
2716
16th to endNight
16%16%49%6%44445%23%
2805
February1st to 15thNight
17%14%6%11%7%2444422%
2473
16th to endNight
19%11%48%6%33445%28%
2044
March1st to 15thNight
21%11%45%5%3334430%
2070
16th to endNight
18%8%36%423335%39%
2054
April1st to 15thNight
24%7%35%324346%34%
1796
16th to endNight
17%6%24434447%39%
1755
May1st to 15thNight
20%6%34425%446%36%
1449
16th to endNight
12%5%25%5%35%46%7%40%
1495
June1st to 15thNight
17%6%25%5%33449%35%
1440
16th to endNight
14%5%244245%6%9%39%
1440
July1st to 15thNight
9%4245%35%5%5%8%46%
1440
16th to endNight
8%5%234245%6%8%46%
1514
August1st to 15thNight
10%5%25%5%3446%8%43%
1581
16th to endNight
9%424325%36%7%50%
1851
September1st to 15thNight
14%42442435%6%47%
1800
16th to endNight
15%42432335%7%47%
1965
October1st to 15thNight
21%7%25%5%34435%36%
2160
16th to endNight
25%8%47%5%33445%26%
2364
November1st to 15thNight
21%8%25%434346%35%
2527
16th to endNight
22%11%46%5%345%45%25%
2730
December1st to 15thNight
22%16%6%7%5%24445%20%
2730
16th to endNight
24%16%5%7%5%35%445%19%
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
62%6%10%14%5%
1553
16th to endDay
63%7%9%10%7%
1768
February1st to 15thDay
65%6%7%15%4
1712
16th to endDay
59%5%12%12%8%1
1574
March1st to 15thDay
60%5%12%14%5%1
1890
16th to endDay
47%5%9%19%14%4
2169
April1st to 15thDay
51%5%8%19%12%2
2152
16th to endDay
45%6%8%20%14%3
2216
May1st to 15thDay
46%7%10%19%13%2
2502
16th to endDay
39%8%14%22%12%1
2622
June1st to 15thDay
46%8%13%21%10%
2520
16th to endDay
40%9%14%22%12%
2520
July1st to 15thDay
34%8%13%30%12%
2371
16th to endDay
37%10%17%24%9%
2487
August1st to 15thDay
36%10%16%22%11%
2363
16th to endDay
32%8%16%29%12%
2339
September1st to 15thDay
38%7%13%26%12%
2160
16th to endDay
38%7%10%30%13%
1992
October1st to 15thDay
47%7%12%21%10%
1800
16th to endDay
56%7%14%15%4
1859
November1st to 15thDay
49%8%13%17%9%1
1657
16th to endDay
59%8%10%14%7%
1560
December1st to 15thDay
66%7%12%10%3
1560
16th to endDay
66%6%10%11%4
1664
January1st to 15thNight
65%6%9%12%5%
2716
16th to endNight
61%6%8%14%7%
2805
February1st to 15thNight
64%6%10%14%4
2482
16th to endNight
56%6%11%16%8%
2044
March1st to 15thNight
56%410%20%7%
2070
16th to endNight
47%410%18%17%2
2054
April1st to 15thNight
50%48%19%15%1
1796
16th to endNight
44%6%9%18%18%3
1755
May1st to 15thNight
46%6%9%18%14%4
1449
16th to endNight
40%6%13%21%14%2
1497
June1st to 15thNight
46%5%13%20%12%
1440
16th to endNight
40%7%13%21%14%
1440
July1st to 15thNight
33%8%9%28%19%1
1360
16th to endNight
32%7%12%28%16%1
1418
August1st to 15thNight
36%9%15%25%13%
1571
16th to endNight
31%6%13%33%14%
1851
September1st to 15thNight
36%6%13%29%12%1
1800
16th to endNight
35%6%10%31%15%
1965
October1st to 15thNight
49%6%10%22%10%
2160
16th to endNight
57%7%13%14%6%
2364
November1st to 15thNight
49%6%13%18%10%2
2527
16th to endNight
58%8%10%15%6%
2730
December1st to 15thNight
63%7%11%13%3
2730
16th to endNight
66%6%10%10%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
24%22%25%20%7%
90
16th to endDay
25%23%31%15%3
120
February1st to 15thDay
27%30%31%10%
135
16th to endDay
33%17%32%13%2
195
March1st to 15thDay
24%15%30%21%7%
270
16th to endDay
26%11%35%18%7%1
288
April1st to 15thDay
26%17%31%13%9%1
270
16th to endDay
20%15%32%16%9%5%
270
May1st to 15thDay
26%8%29%20%11%3
288
16th to endDay
17%11%32%23%11%3
331
June1st to 15thDay
19%9%35%22%9%2
315
16th to endDay
17%8%31%26%12%3
315
July1st to 15thDay
13%6%24%31%18%5%
305
16th to endDay
12%6%28%34%11%5%
326
August1st to 15thDay
11%6%26%28%22%5%
313
16th to endDay
13%7%25%23%17%11%
332
September1st to 15thDay
17%5%26%23%17%10%
315
16th to endDay
15%6%25%23%18%10%
314
October1st to 15thDay
23%13%25%19%13%4
315
16th to endDay
28%21%26%17%5%
320
November1st to 15thDay
20%14%33%21%8%1
221
16th to endDay
24%17%37%10%10%
90
December1st to 15thDay
22%28%24%14%8%1
90
16th to endDay
32%28%32%6%1
96
January1st to 15thNight
30%20%29%15%3
780
16th to endNight
26%16%31%20%4
832
February1st to 15thNight
24%18%35%17%3
764
16th to endNight
26%13%31%21%6%
659
March1st to 15thNight
27%15%30%22%3
720
16th to endNight
22%11%31%24%9%1
768
April1st to 15thNight
27%12%32%22%4
718
16th to endNight
21%12%30%23%10%1
675
May1st to 15thNight
23%5%27%31%11%1
369
16th to endNight
11%6%31%34%14%1
375
June1st to 15thNight
18%5%27%32%14%
360
16th to endNight
15%427%36%16%
360
July1st to 15thNight
9%325%37%21%2
340
16th to endNight
8%326%41%18%1
376
August1st to 15thNight
13%324%31%23%3
500
16th to endNight
10%425%31%24%2
705
September1st to 15thNight
15%5%23%29%22%3
720
16th to endNight
16%8%21%26%20%6%
717
October1st to 15thNight
24%13%25%19%15%2
720
16th to endNight
29%14%28%21%6%
768
November1st to 15thNight
26%11%29%20%10%1
760
16th to endNight
31%19%25%15%8%
780
December1st to 15thNight
32%21%24%17%3
780
16th to endNight
31%18%33%14%2
832
Page generated at 2018-02-23 11:21:36. Version ac04

Copyright 2018 A. Danko


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