Saddlebrooke
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Saddlebrooke clear sky chart from 2005-11-05 to

2017-09-12
.

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
70%
15540
35%
46846
29%
15501
76%
15501
48%
23276

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
67%
719
31%
2327
30%
716
72%
716
45%
1133
January16th to endNight
62%
768
34%
2496
32%
768
71%
768
37%
1323
February1st to 15thNight
67%
700
35%
2214
31%
700
76%
700
47%
1078
February16th to endNight
57%
632
36%
1834
31%
632
65%
632
43%
980
March1st to 15thNight
60%
720
37%
1980
28%
720
69%
720
49%
1038
March16th to endNight
66%
768
38%
2112
25%
768
76%
768
55%
1052
April1st to 15thNight
58%
679
33%
1938
21%
679
69%
679
50%
961
April16th to endNight
65%
540
45%
1784
35%
540
80%
540
67%
668
May1st to 15thNight
66%
539
39%
1619
27%
539
77%
539
64%
684
May16th to endNight
69%
561
41%
1684
31%
561
76%
561
67%
695
June1st to 15thNight
78%
540
34%
1620
29%
540
80%
540
66%
695
June16th to endNight
83%
540
31%
1620
26%
540
83%
540
58%
740
July1st to 15thNight
79%
510
20%
1530
17%
510
79%
510
38%
870
July16th to endNight
77%
564
17%
1593
16%
531
76%
531
28%
1038
August1st to 15thNight
85%
539
24%
1611
23%
536
85%
536
39%
906
August16th to endNight
82%
587
30%
1865
31%
587
83%
587
37%
1020
September1st to 15thNight
75%
706
29%
1942
25%
706
76%
706
40%
1158
September16th to endNight
78%
656
40%
1815
30%
656
82%
656
62%
869
October1st to 15thNight
72%
660
40%
1919
30%
660
79%
660
59%
895
October16th to endNight
80%
704
43%
2112
36%
704
85%
704
63%
933
November1st to 15thNight
74%
700
42%
2100
35%
700
81%
700
60%
934
November16th to endNight
68%
720
37%
2295
34%
720
74%
720
47%
1108
December1st to 15thNight
65%
720
36%
2340
34%
720
71%
720
44%
1152
December16th to endNight
59%
768
33%
2496
32%
768
65%
768
35%
1346

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
3313323446%62%
47808
Night
3213323446%64%
47042
TransparencyDay
22%35%11%26%30%
47503
Night
21%35%13%26%30%
46848
SeeingDay
8%11%27%32%16%3
5375
Night
5%414%34%33%8%
15548

By Month

Percentage Cloud Cover SW (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
4424414345%61%
1611
16th to endDay
6%414323445%59%
1728
February1st to 15thDay
5%413313335%64%
1646
16th to endDay
5%415%413346%58%
1639
March1st to 15thDay
3324323336%62%
1980
16th to endDay
2322312335%70%
2112
April1st to 15thDay
1212323345%68%
2009
16th to endDay
11211212478%
2172
May1st to 15thDay
11221333475%
2331
16th to endDay
11121122379%
2429
June1st to 15thDay
121121223477%
2340
16th to endDay
111222345%5%70%
2340
July1st to 15thDay
33245%36%7%8%10%42%
2340
16th to endDay
7%6%36%8%47%8%9%10%29%
2467
August1st to 15thDay
6%425%6%46%6%7%8%40%
2340
16th to endDay
3325%6%46%6%7%8%45%
2334
September1st to 15thDay
5%4236%36%5%7%7%46%
1937
16th to endDay
322323445%67%
1815
October1st to 15thDay
211232333471%
1709
16th to endDay
121211233474%
1760
November1st to 15thDay
1112212346%72%
1759
16th to endDay
231332233468%
1662
December1st to 15thDay
5%224323445%60%
1620
16th to endDay
431432345%6%57%
1728
January1st to 15thNight
4323413345%63%
2327
16th to endNight
6%42442444456%
2496
February1st to 15thNight
3323313345%64%
2203
16th to endNight
34244235%45%59%
1834
March1st to 15thNight
232332333465%
1980
16th to endNight
2112322335%69%
2112
April1st to 15thNight
221332334467%
1938
16th to endNight
1111112383%
1784
May1st to 15thNight
1111235%6%74%
1619
16th to endNight
11111122481%
1684
June1st to 15thNight
11122222478%
1620
16th to endNight
1112224335%72%
1620
July1st to 15thNight
23235%36%6%9%11%45%
1620
16th to endNight
3425%5%5%7%8%8%15%31%
1701
August1st to 15thNight
2313435%7%8%12%48%
1620
16th to endNight
21236%446%7%10%48%
1865
September1st to 15thNight
44245%25%5%5%7%51%
1942
16th to endNight
111222233472%
1815
October1st to 15thNight
1212212335%72%
1919
16th to endNight
12221222377%
2112
November1st to 15thNight
111231234473%
2100
16th to endNight
421331433466%
2295
December1st to 15thNight
5%312323347%60%
2340
16th to endNight
5%5%25%42335%456%
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
26%2411%28%26%
1612
16th to endDay
27%2314%25%25%
1728
February1st to 15thDay
23%1313%26%30%
1646
16th to endDay
28%2212%30%23%
1639
March1st to 15thDay
23%225%33%32%
1980
16th to endDay
18%229%35%32%
2112
April1st to 15thDay
18%116%38%32%
2009
16th to endDay
12%118%28%48%
2172
May1st to 15thDay
14%127%28%46%
2331
16th to endDay
12%217%30%46%
2432
June1st to 15thDay
12%11422%57%
2340
16th to endDay
16%236%19%51%
2340
July1st to 15thDay
31%9%12%15%13%17%
2201
16th to endDay
43%9%16%20%8%1
2312
August1st to 15thDay
36%7%10%15%19%11%
2325
16th to endDay
32%7%11%16%20%12%
2334
September1st to 15thDay
33%6%9%17%16%16%
1937
16th to endDay
19%339%32%31%
1815
October1st to 15thDay
17%3312%27%36%
1709
16th to endDay
14%138%29%41%
1760
November1st to 15thDay
13%1211%36%34%
1759
16th to endDay
20%2210%27%36%
1662
December1st to 15thDay
25%2415%31%20%
1620
16th to endDay
27%3418%30%14%
1728
January1st to 15thNight
23%2411%29%28%
2327
16th to endNight
29%2314%27%21%
2496
February1st to 15thNight
22%2414%26%30%
2214
16th to endNight
26%1312%32%21%
1834
March1st to 15thNight
22%228%29%33%
1980
16th to endNight
18%2211%35%30%
2112
April1st to 15thNight
20%128%39%27%
1938
16th to endNight
8%119%30%48%
1784
May1st to 15thNight
11%139%30%42%
1620
16th to endNight
10%118%26%51%
1685
June1st to 15thNight
12%115%20%59%
1620
16th to endNight
15%33418%55%
1620
July1st to 15thNight
26%8%15%16%15%17%
1530
16th to endNight
36%10%20%21%9%2
1593
August1st to 15thNight
25%8%14%19%17%14%
1611
16th to endNight
28%6%12%19%19%13%
1865
September1st to 15thNight
29%5%7%22%19%15%
1942
16th to endNight
15%2311%33%32%
1815
October1st to 15thNight
16%2315%26%36%
1919
16th to endNight
14%1212%24%44%
2112
November1st to 15thNight
14%2213%34%33%
2100
16th to endNight
22%2311%22%38%
2295
December1st to 15thNight
24%2415%30%23%
2340
16th to endNight
30%25%16%26%17%
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
17%11%27%33%8%1
90
16th to endDay
12%5%32%27%18%4
96
February1st to 15thDay
8%13%27%35%13%1
161
16th to endDay
13%24%31%22%5%
238
March1st to 15thDay
9%20%34%20%12%2
270
16th to endDay
5%26%32%21%11%2
288
April1st to 15thDay
9%27%31%21%7%3
269
16th to endDay
8%27%35%18%5%2
270
May1st to 15thDay
7%19%43%18%8%3
288
16th to endDay
313%41%32%8%
330
June1st to 15thDay
48%42%31%10%2
315
16th to endDay
5%229%40%19%2
315
July1st to 15thDay
6%116%47%23%3
305
16th to endDay
9%111%39%29%8%
327
August1st to 15thDay
9%28%41%29%8%
315
16th to endDay
5%111%40%31%8%
332
September1st to 15thDay
11%319%43%17%6%
300
16th to endDay
8%9%29%36%12%3
255
October1st to 15thDay
5%12%30%30%16%4
149
16th to endDay
8%120%40%28%1
96
November1st to 15thDay
416%24%31%22%1
90
16th to endDay
6%17%28%34%11%1
90
December1st to 15thDay
6%7%17%42%23%2
90
16th to endDay
18%14%23%34%7%1
96
January1st to 15thNight
7%216%42%25%5%
720
16th to endNight
9%5%16%39%23%5%
768
February1st to 15thNight
6%415%37%29%6%
704
16th to endNight
8%8%20%40%19%2
632
March1st to 15thNight
6%7%22%34%23%6%
720
16th to endNight
36%18%36%28%6%
768
April1st to 15thNight
48%22%40%21%2
679
16th to endNight
29%21%39%23%4
540
May1st to 15thNight
17%21%37%27%4
540
16th to endNight
25%20%37%28%4
563
June1st to 15thNight
2113%41%35%4
540
16th to endNight
227%37%44%6%
540
July1st to 15thNight
315%25%53%10%
510
16th to endNight
5%318%54%17%
564
August1st to 15thNight
5%114%58%19%
539
16th to endNight
5%119%53%19%
587
September1st to 15thNight
5%16%24%46%14%
706
16th to endNight
3111%32%37%13%
656
October1st to 15thNight
3215%37%31%8%
660
16th to endNight
2210%35%36%12%
704
November1st to 15thNight
2414%38%31%7%
700
16th to endNight
6%5%15%36%29%6%
720
December1st to 15thNight
9%416%33%31%4
720
16th to endNight
10%5%16%38%22%6%
768
Page generated at 2017-09-13 04:39:10. Version ac04

Copyright 2017 A. Danko


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