Kendale Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kendale Observatory clear sky chart from 2005-11-05 to 2017-10-06.

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
64%
16349
18%
47159
15%
16310
67%
16310
29%
30383

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
56%
716
16%
2327
14%
716
61%
716
26%
1438
January16th to endNight
55%
768
26%
2457
20%
768
63%
768
32%
1400
February1st to 15thNight
54%
702
27%
2092
22%
699
60%
699
35%
1218
February16th to endNight
61%
631
31%
1735
22%
631
68%
631
41%
981
March1st to 15thNight
58%
720
25%
1980
18%
720
64%
720
37%
1180
March16th to endNight
62%
768
25%
2112
21%
768
66%
768
40%
1226
April1st to 15thNight
70%
718
25%
1976
21%
718
73%
718
48%
1065
April16th to endNight
61%
720
25%
1811
15%
720
65%
720
40%
1114
May1st to 15thNight
73%
719
24%
1799
16%
719
75%
719
49%
1025
May16th to endNight
68%
619
16%
1741
14%
619
68%
619
27%
1176
June1st to 15thNight
61%
540
8%
1620
8%
540
62%
540
16%
1231
June16th to endNight
77%
540
7%
1620
7%
540
77%
540
22%
1141
July1st to 15thNight
75%
510
5%
1530
5%
510
75%
510
21%
1098
July16th to endNight
82%
564
10%
1595
10%
531
82%
531
30%
1017
August1st to 15thNight
74%
617
8%
1687
7%
614
74%
614
27%
1144
August16th to endNight
69%
764
6%
2036
5%
764
69%
764
21%
1489
September1st to 15thNight
67%
720
5%
1980
5%
720
67%
720
17%
1509
September16th to endNight
65%
717
6%
1980
7%
717
65%
717
16%
1542
October1st to 15thNight
67%
684
14%
1983
15%
684
68%
684
21%
1409
October16th to endNight
56%
704
18%
2112
18%
704
59%
704
23%
1440
November1st to 15thNight
63%
700
24%
2101
21%
700
69%
700
30%
1311
November16th to endNight
57%
720
26%
2160
21%
720
64%
720
29%
1357
December1st to 15thNight
59%
720
23%
2229
20%
720
64%
720
26%
1423
December16th to endNight
65%
768
24%
2496
25%
768
69%
768
32%
1449

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
8%6%37%8%5%8%7%7%10%27%
48020
Night
6%425%5%35%6%7%10%40%
47365
TransparencyDay
48%9%13%15%9%2
47721
Night
36%8%18%21%12%2
47168
SeeingDay
9%216%22%24%23%
6160
Night
8%114%31%30%14%
16358

By Month

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
9%6%36%7%5%6%6%7%10%30%
1611
16th to endDay
7%5%45%5%5%6%6%6%10%35%
1764
February1st to 15thDay
9%5%35%6%46%45%8%40%
1763
16th to endDay
6%425%5%36%5%7%10%42%
1738
March1st to 15thDay
6%5%346%46%7%7%10%37%
1980
16th to endDay
6%6%36%6%35%6%6%10%37%
2111
April1st to 15thDay
5%4146%36%7%8%13%37%
1972
16th to endDay
7%416%6%47%6%8%11%35%
2148
May1st to 15thDay
4315%7%37%7%7%10%40%
2152
16th to endDay
9%7%38%9%5%9%8%8%9%19%
2381
June1st to 15thDay
12%9%5%10%9%6%9%7%7%7%13%
2340
16th to endDay
7%6%5%10%9%7%10%9%9%9%14%
2340
July1st to 15thDay
6%7%49%10%6%9%7%9%10%17%
2340
16th to endDay
6%6%37%9%6%10%10%10%10%19%
2465
August1st to 15thDay
6%8%38%8%6%9%8%9%10%20%
2247
16th to endDay
9%6%48%10%6%9%9%8%11%16%
2160
September1st to 15thDay
9%6%49%10%6%9%9%9%9%13%
1980
16th to endDay
11%11%410%10%7%9%7%7%6%14%
1980
October1st to 15thDay
9%8%38%11%5%8%6%7%10%20%
1775
16th to endDay
14%6%37%7%35%6%7%9%28%
1760
November1st to 15thDay
8%428%7%47%6%7%8%34%
1757
16th to endDay
9%6%45%6%5%7%6%5%7%35%
1800
December1st to 15thDay
9%6%36%7%5%6%5%7%8%32%
1728
16th to endDay
6%436%6%47%6%7%11%33%
1728
January1st to 15thNight
7%425%5%47%6%7%10%38%
2327
16th to endNight
44245%35%5%7%11%46%
2457
February1st to 15thNight
8%425%5%2435%8%50%
2090
16th to endNight
4215%425%45%9%54%
1735
March1st to 15thNight
42245%35%6%5%8%50%
1980
16th to endNight
43135%25%5%5%10%51%
2112
April1st to 15thNight
22134335%6%10%57%
1976
16th to endNight
6%3145%345%7%9%50%
1811
May1st to 15thNight
221332446%12%56%
1799
16th to endNight
7%5%35%6%46%6%8%9%37%
1740
June1st to 15thNight
11%6%27%7%5%7%8%8%10%23%
1620
16th to endNight
44246%48%8%11%14%29%
1620
July1st to 15thNight
4336%6%5%6%6%10%14%32%
1620
16th to endNight
2315%5%35%7%8%13%40%
1703
August1st to 15thNight
3426%6%35%8%8%14%36%
1698
16th to endNight
5%437%7%37%7%9%13%30%
2036
September1st to 15thNight
5%437%8%5%7%9%9%11%27%
1980
16th to endNight
8%6%27%8%5%8%7%9%11%23%
1980
October1st to 15thNight
6%5%17%6%5%7%8%8%12%30%
1983
16th to endNight
11%7%36%6%345%6%8%35%
2112
November1st to 15thNight
6%425%5%345%6%8%44%
2101
16th to endNight
7%435%5%36%5%6%8%43%
2160
December1st to 15thNight
8%5%346%35%5%7%11%39%
2229
16th to endNight
5%4245%25%6%7%10%46%
2496

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
46%7%12%17%11%5%
1612
16th to endDay
42%5%11%17%16%5%
1764
February1st to 15thDay
39%6%9%21%18%5%
1765
16th to endDay
33%6%12%26%16%4
1738
March1st to 15thDay
38%7%11%22%17%3
1980
16th to endDay
39%5%13%22%14%5%
2112
April1st to 15thDay
33%8%14%25%16%2
1972
16th to endDay
38%7%12%19%17%4
2148
May1st to 15thDay
35%7%13%23%14%5%
2152
16th to endDay
53%11%12%17%5%
2385
June1st to 15thDay
66%10%11%9%2
2340
16th to endDay
59%12%16%9%1
2340
July1st to 15thDay
55%14%21%8%
2201
16th to endDay
50%15%23%9%
2310
August1st to 15thDay
51%14%18%13%1
2234
16th to endDay
56%14%18%9%
2160
September1st to 15thDay
59%14%17%7%
1980
16th to endDay
65%11%12%7%2
1980
October1st to 15thDay
55%11%12%12%7%
1775
16th to endDay
49%7%10%14%13%4
1760
November1st to 15thDay
44%7%9%15%18%5%
1757
16th to endDay
44%6%9%12%20%6%
1800
December1st to 15thDay
47%5%11%15%17%2
1728
16th to endDay
41%8%8%21%16%3
1728
January1st to 15thNight
38%5%18%22%11%3
2327
16th to endNight
31%6%12%27%17%4
2457
February1st to 15thNight
33%410%25%20%7%
2099
16th to endNight
26%5%13%26%20%6%
1735
March1st to 15thNight
31%5%11%27%18%5%
1980
16th to endNight
28%6%15%26%19%3
2112
April1st to 15thNight
22%5%17%33%18%2
1976
16th to endNight
29%6%14%24%20%3
1811
May1st to 15thNight
22%6%16%32%17%4
1800
16th to endNight
40%7%16%26%8%
1742
June1st to 15thNight
52%10%20%13%3
1620
16th to endNight
38%15%31%13%
1620
July1st to 15thNight
40%15%31%11%
1530
16th to endNight
32%11%37%16%1
1595
August1st to 15thNight
35%13%30%18%1
1687
16th to endNight
42%14%29%12%
2036
September1st to 15thNight
46%16%24%10%1
1980
16th to endNight
50%14%20%10%3
1980
October1st to 15thNight
44%11%16%15%9%1
1983
16th to endNight
46%5%11%19%12%4
2112
November1st to 15thNight
37%5%10%19%22%4
2101
16th to endNight
39%411%18%19%7%
2160
December1st to 15thNight
39%7%13%19%17%2
2229
16th to endNight
32%6%11%26%19%2
2496

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
18%13%36%24%6%
90
16th to endDay
12%16%35%27%6%2
96
February1st to 15thDay
410%39%26%18%
104
16th to endDay
9%328%34%23%1
239
March1st to 15thDay
5%7%32%34%17%2
270
16th to endDay
6%6%30%25%22%6%
288
April1st to 15thDay
5%325%27%26%10%
270
16th to endDay
7%125%25%27%12%
270
May1st to 15thDay
5%221%22%29%18%
288
16th to endDay
8%19%23%31%25%
331
June1st to 15thDay
14%112%18%20%31%
315
16th to endDay
7%413%31%42%
315
July1st to 15thDay
5%115%31%46%
305
16th to endDay
5%414%25%49%
326
August1st to 15thDay
9%415%21%48%
313
16th to endDay
13%7%12%27%39%
332
September1st to 15thDay
10%5%13%22%46%
315
16th to endDay
12%6%11%29%40%
314
October1st to 15thDay
9%214%26%31%16%
278
16th to endDay
17%219%28%18%13%
272
November1st to 15thDay
9%18%30%31%8%
265
16th to endDay
12%7%23%32%21%2
270
December1st to 15thDay
21%314%35%19%5%
198
16th to endDay
7%226%44%18%1
96
January1st to 15thNight
9%422%36%24%3
720
16th to endNight
6%426%42%17%1
768
February1st to 15thNight
9%226%40%19%1
704
16th to endNight
6%223%45%21%
631
March1st to 15thNight
6%224%44%19%2
720
16th to endNight
6%222%43%22%1
768
April1st to 15thNight
3119%45%26%2
718
16th to endNight
6%121%42%24%2
720
May1st to 15thNight
315%44%32%3
720
16th to endNight
8%19%29%38%11%
621
June1st to 15thNight
14%418%38%22%
540
16th to endNight
3412%37%40%
540
July1st to 15thNight
5%29%46%36%
510
16th to endNight
418%36%49%
564
August1st to 15thNight
5%210%43%38%
617
16th to endNight
8%5%13%38%33%
764
September1st to 15thNight
9%411%33%40%
720
16th to endNight
10%313%38%33%
717
October1st to 15thNight
9%9%29%38%12%
684
16th to endNight
14%115%29%27%11%
704
November1st to 15thNight
9%217%37%29%4
700
16th to endNight
10%120%37%24%4
720
December1st to 15thNight
10%218%38%27%2
720
16th to endNight
7%217%41%27%4
768
Page generated at 2017-10-07 14:07:51. Version ac04

Copyright 2017 A. Danko


Kendale Observatory Clear Sky Chart | Charts Home