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 2017-05-01.

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%
14398
13%
45694
8%
14367
36%
14367
17%
32593

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
11%
720
8%
2506
3%
716
18%
716
6%
2006
January16th to endNight
19%
768
11%
2589
5%
768
26%
768
10%
2003
February1st to 15thNight
13%
704
9%
2287
3%
701
21%
701
9%
1814
February16th to endNight
22%
631
13%
1956
5%
631
30%
631
13%
1466
March1st to 15thNight
21%
720
14%
2070
7%
720
29%
720
16%
1534
March16th to endNight
30%
768
19%
2054
9%
768
38%
768
24%
1423
April1st to 15thNight
23%
718
15%
1796
4%
718
28%
718
21%
1307
April16th to endNight
32%
675
17%
1755
7%
675
37%
675
24%
1218
May1st to 15thNight
40%
341
18%
1337
16%
341
48%
341
18%
863
May16th to endNight
43%
342
15%
1369
16%
342
52%
342
21%
827
June1st to 15thNight
40%
330
12%
1320
14%
330
48%
330
17%
863
June16th to endNight
48%
330
10%
1320
14%
330
53%
330
21%
799
July1st to 15thNight
55%
310
16%
1240
21%
310
61%
310
27%
694
July16th to endNight
56%
348
14%
1306
13%
326
60%
326
27%
731
August1st to 15thNight
50%
458
15%
1439
10%
456
54%
456
26%
906
August16th to endNight
53%
646
21%
1696
10%
646
58%
646
37%
1050
September1st to 15thNight
50%
660
18%
1650
9%
660
53%
660
33%
1082
September16th to endNight
46%
657
22%
1801
14%
657
51%
657
30%
1159
October1st to 15thNight
31%
660
17%
1980
12%
660
39%
660
18%
1410
October16th to endNight
20%
704
9%
2167
3%
704
27%
704
11%
1689
November1st to 15thNight
28%
700
17%
2328
12%
700
36%
700
17%
1601
November16th to endNight
19%
720
12%
2520
7%
720
26%
720
9%
1948
December1st to 15thNight
16%
720
7%
2520
2%
720
22%
720
8%
1998
December16th to endNight
11%
768
7%
2688
2%
768
18%
768
7%
2202

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%
46073
Night
18%9%36%5%34446%33%
45864
Cloud CoverDay
17%8%35%5%3445%7%35%
46083
Night
18%9%36%5%34446%32%
45869
TransparencyDay
48%7%12%20%10%1
45761
Night
51%6%11%19%10%1
45694
SeeingDay
20%12%29%21%12%3
4936
Night
23%12%28%23%10%1
14399

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
24%12%37%5%24445%25%
1432
16th to endDay
15%15%49%7%46%5%45%22%
1632
February1st to 15thDay
16%11%6%12%9%35%445%21%
1575
16th to endDay
21%12%45%6%2436%6%26%
1516
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%
2215
May1st to 15thDay
15%5%35%6%35%5%5%6%37%
2295
16th to endDay
13%5%245%245%6%8%41%
2394
June1st to 15thDay
19%5%35%5%3446%8%34%
2310
16th to endDay
13%5%24435%45%8%41%
2310
July1st to 15thDay
10%4244345%6%9%46%
2310
16th to endDay
10%4245%35%6%7%9%41%
2458
August1st to 15thDay
11%4235%35%5%6%9%41%
2178
16th to endDay
12%41332346%10%46%
2143
September1st to 15thDay
16%5%2432345%7%43%
1980
16th to endDay
15%6%2443335%7%43%
1827
October1st to 15thDay
21%5%25%434446%37%
1650
16th to endDay
27%7%46%424446%26%
1705
November1st to 15thDay
15%6%36%7%35%5%47%34%
1527
16th to endDay
25%10%36%5%35%45%5%25%
1440
December1st to 15thDay
23%14%46%5%35%5%35%20%
1440
16th to endDay
25%16%5%6%5%24435%18%
1536
January1st to 15thNight
22%15%5%8%5%3444421%
2506
16th to endNight
16%15%48%6%34445%24%
2589
February1st to 15thNight
17%14%5%9%7%34435%23%
2285
16th to endNight
19%10%48%6%34436%29%
1956
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
19%6%2343435%6%38%
1337
16th to endNight
12%4345%35%45%7%42%
1367
June1st to 15thNight
18%5%35%43435%8%35%
1320
16th to endNight
13%425%5%345%5%8%41%
1320
July1st to 15thNight
8%4235%35%5%5%8%48%
1320
16th to endNight
8%4244235%7%9%46%
1402
August1st to 15thNight
11%5%25%5%3446%8%43%
1449
16th to endNight
9%423425%46%8%50%
1696
September1st to 15thNight
14%5%25%324346%47%
1650
16th to endNight
16%33332335%7%45%
1801
October1st to 15thNight
20%7%346%34446%35%
1980
16th to endNight
24%8%48%5%34445%26%
2167
November1st to 15thNight
20%7%25%424446%36%
2328
16th to endNight
23%11%45%5%35%45%5%26%
2520
December1st to 15thNight
23%15%47%5%23446%23%
2520
16th to endNight
24%15%5%6%5%3445%5%18%
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
24%13%37%6%2444423%
1432
16th to endDay
15%14%5%9%7%35%5%5%5%20%
1632
February1st to 15thDay
16%13%6%10%8%35%44421%
1575
16th to endDay
21%12%45%5%35%346%26%
1516
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
19%5%25%5%34445%39%
2215
May1st to 15thDay
15%6%35%5%245%5%7%37%
2295
16th to endDay
12%5%25%435%45%9%41%
2394
June1st to 15thDay
19%6%35%5%2445%7%35%
2310
16th to endDay
14%424435%5%5%7%42%
2310
July1st to 15thDay
10%42443445%9%46%
2310
16th to endDay
11%414425%6%6%9%42%
2458
August1st to 15thDay
12%5%244245%6%9%42%
2178
16th to endDay
12%41332445%9%47%
2143
September1st to 15thDay
16%4245%3435%6%43%
1980
16th to endDay
15%5%34423446%44%
1827
October1st to 15thDay
20%7%25%5%2435%6%36%
1650
16th to endDay
28%7%35%5%34446%26%
1705
November1st to 15thDay
15%7%36%6%35%5%46%33%
1527
16th to endDay
24%11%47%6%24445%23%
1440
December1st to 15thDay
25%15%47%5%445%45%19%
1440
16th to endDay
25%17%5%6%5%35%345%16%
1536
January1st to 15thNight
22%16%5%9%5%3434420%
2506
16th to endNight
16%16%48%6%44445%23%
2589
February1st to 15thNight
17%13%6%11%7%2444422%
2278
16th to endNight
19%11%48%6%34445%28%
1956
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
19%5%34425%346%38%
1337
16th to endNight
12%5%35%435%46%6%41%
1367
June1st to 15thNight
17%7%35%5%34449%35%
1320
16th to endNight
13%4245%25%5%6%9%40%
1320
July1st to 15thNight
8%3145%35%5%5%8%47%
1320
16th to endNight
8%5%234345%6%9%46%
1402
August1st to 15thNight
10%5%25%5%3446%7%42%
1449
16th to endNight
9%424325%36%7%49%
1696
September1st to 15thNight
14%42442435%6%47%
1650
16th to endNight
16%424323347%45%
1801
October1st to 15thNight
21%6%35%5%34436%35%
1980
16th to endNight
25%9%47%5%34445%25%
2167
November1st to 15thNight
19%8%25%434446%35%
2328
16th to endNight
23%11%5%6%5%35%5%45%24%
2520
December1st to 15thNight
23%15%6%6%42445%5%21%
2520
16th to endNight
25%16%5%7%5%35%445%17%
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
61%6%10%14%5%
1433
16th to endDay
63%7%9%10%8%
1632
February1st to 15thDay
65%6%8%14%4
1577
16th to endDay
58%5%12%13%8%1
1516
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
2215
May1st to 15thDay
44%7%10%20%14%2
2295
16th to endDay
39%9%13%23%13%1
2398
June1st to 15thDay
47%8%13%19%9%
2310
16th to endDay
40%8%14%22%12%1
2310
July1st to 15thDay
32%7%14%31%12%
2161
16th to endDay
36%10%17%24%9%
2291
August1st to 15thDay
37%10%16%22%11%1
2164
16th to endDay
33%8%16%29%11%
2143
September1st to 15thDay
40%7%13%27%11%
1980
16th to endDay
40%7%9%29%12%
1827
October1st to 15thDay
47%7%13%20%11%
1650
16th to endDay
58%7%13%15%4
1705
November1st to 15thDay
48%8%13%17%9%1
1527
16th to endDay
60%7%10%13%7%
1440
December1st to 15thDay
66%7%12%10%2
1440
16th to endDay
68%7%10%10%3
1536
January1st to 15thNight
66%6%9%12%5%
2506
16th to endNight
61%6%8%15%8%
2589
February1st to 15thNight
63%6%10%14%4
2287
16th to endNight
56%6%11%16%8%
1956
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
45%6%8%18%15%5%
1337
16th to endNight
40%6%12%21%15%3
1369
June1st to 15thNight
48%5%13%20%11%
1320
16th to endNight
39%7%14%22%15%1
1320
July1st to 15thNight
32%7%9%28%19%1
1240
16th to endNight
32%8%13%29%15%2
1306
August1st to 15thNight
36%9%15%23%14%
1439
16th to endNight
31%6%13%33%14%
1696
September1st to 15thNight
37%6%14%30%11%
1650
16th to endNight
37%6%10%30%13%
1801
October1st to 15thNight
50%6%10%21%11%
1980
16th to endNight
59%8%12%12%6%
2167
November1st to 15thNight
48%6%13%18%10%2
2328
16th to endNight
59%8%9%14%6%
2520
December1st to 15thNight
62%7%11%13%3
2520
16th to endNight
67%6%10%10%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
21%26%23%18%10%
60
16th to endDay
28%23%27%15%5%
80
February1st to 15thDay
21%35%28%13%1
90
16th to endDay
31%17%33%14%2
175
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
20%9%28%23%13%4
229
16th to endDay
15%11%30%25%13%3
267
June1st to 15thDay
20%10%32%21%10%3
255
16th to endDay
16%5%28%30%14%3
255
July1st to 15thDay
11%6%23%31%20%6%
245
16th to endDay
11%5%31%33%12%5%
270
August1st to 15thDay
12%5%26%27%22%5%
253
16th to endDay
15%5%26%23%17%10%
268
September1st to 15thDay
17%5%26%21%18%10%
255
16th to endDay
18%7%28%22%15%7%
254
October1st to 15thDay
21%13%25%20%14%3
255
16th to endDay
32%19%27%16%4
262
November1st to 15thDay
16%14%33%25%8%1
181
16th to endDay
23%13%35%15%13%
60
December1st to 15thDay
18%31%25%13%11%
60
16th to endDay
37%32%23%41
64
January1st to 15thNight
31%20%29%14%4
720
16th to endNight
26%16%32%20%5%
768
February1st to 15thNight
24%18%36%17%3
704
16th to endNight
25%14%31%22%6%
631
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
22%428%31%12%1
341
16th to endNight
11%6%30%35%14%2
343
June1st to 15thNight
19%6%27%31%14%
330
16th to endNight
13%426%37%17%
330
July1st to 15thNight
8%424%38%21%2
310
16th to endNight
8%328%41%17%1
348
August1st to 15thNight
13%326%29%23%3
458
16th to endNight
11%425%31%25%2
646
September1st to 15thNight
16%5%23%28%22%3
660
16th to endNight
17%8%23%27%18%4
657
October1st to 15thNight
25%13%25%18%15%1
660
16th to endNight
30%13%28%21%5%
704
November1st to 15thNight
25%12%29%20%10%1
700
16th to endNight
31%18%25%15%8%
720
December1st to 15thNight
33%21%24%16%3
720
16th to endNight
32%17%31%14%21
768
Page generated at 2017-05-02 08:43:44. Version ac04

Copyright 2017 A. Danko


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