The Saddle
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the The Saddle clear sky chart from 2005-11-05 to 2017-12-02.

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
39%
16093
23%
47810
12%
16054
50%
16054
24%
29644

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%
719
25%
2327
7%
716
37%
716
16%
1366
January16th to endNight
17%
768
24%
2496
7%
768
39%
768
18%
1470
February1st to 15thNight
15%
701
24%
2287
6%
701
36%
701
17%
1346
February16th to endNight
16%
631
27%
1863
7%
631
36%
631
18%
1146
March1st to 15thNight
24%
720
25%
1980
10%
720
39%
720
22%
1263
March16th to endNight
23%
768
19%
2112
8%
768
34%
768
21%
1393
April1st to 15thNight
28%
718
21%
1885
6%
718
39%
718
25%
1198
April16th to endNight
34%
642
23%
1722
8%
642
44%
642
28%
1099
May1st to 15thNight
36%
540
16%
1620
8%
540
42%
540
21%
1079
May16th to endNight
53%
561
15%
1684
9%
561
57%
561
29%
1064
June1st to 15thNight
63%
540
15%
1620
13%
540
65%
540
31%
1026
June16th to endNight
66%
540
18%
1620
14%
540
69%
540
34%
979
July1st to 15thNight
65%
510
12%
1530
10%
510
67%
510
30%
962
July16th to endNight
71%
564
17%
1595
14%
531
74%
531
34%
956
August1st to 15thNight
61%
539
17%
1609
14%
536
63%
536
27%
1051
August16th to endNight
64%
671
18%
1817
14%
671
66%
671
31%
1188
September1st to 15thNight
59%
720
23%
1902
16%
720
62%
720
31%
1240
September16th to endNight
49%
717
21%
1980
16%
717
53%
717
24%
1355
October1st to 15thNight
47%
720
26%
2141
22%
720
55%
720
27%
1328
October16th to endNight
38%
768
35%
2304
21%
768
57%
768
32%
1282
November1st to 15thNight
39%
760
27%
2320
17%
760
53%
760
28%
1365
November16th to endNight
33%
780
30%
2535
16%
780
51%
780
25%
1396
December1st to 15thNight
27%
728
24%
2365
10%
728
43%
728
17%
1477
December16th to endNight
20%
768
23%
2496
8%
768
38%
768
14%
1615

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
13%5%25%5%35%5%6%7%37%
48626
Night
12%5%2443445%7%44%
48003
Cloud CoverDay
13%5%25%5%35%5%5%7%37%
48636
Night
12%5%2443445%7%44%
48007
TransparencyDay
43%411%21%15%3
48337
Night
38%411%23%17%4
47810
SeeingDay
18%13%20%21%15%8%
5907
Night
17%14%21%25%17%3
16099

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
12%7%35%5%3446%6%41%
1611
16th to endDay
12%6%245%3446%5%43%
1728
February1st to 15thDay
11%6%35%6%4435%6%42%
1575
16th to endDay
12%6%35%436%448%40%
1608
March1st to 15thDay
14%5%243345%5%6%44%
1969
16th to endDay
17%6%35%5%35%35%5%37%
2112
April1st to 15thDay
10%4243345%5%9%47%
2062
16th to endDay
16%6%36%5%3445%6%37%
2249
May1st to 15thDay
18%5%26%6%45%5%5%7%31%
2331
16th to endDay
13%6%26%7%36%6%6%8%33%
2431
June1st to 15thDay
10%435%6%46%7%7%10%32%
2340
16th to endDay
8%5%25%6%36%6%7%10%35%
2340
July1st to 15thDay
11%5%36%8%5%6%7%8%8%26%
2340
16th to endDay
9%6%37%9%5%7%7%8%9%25%
2465
August1st to 15thDay
13%5%37%7%47%6%8%8%25%
2340
16th to endDay
12%6%25%6%46%7%7%10%29%
2372
September1st to 15thDay
15%6%25%6%345%5%8%36%
2055
16th to endDay
23%6%25%5%24446%32%
1980
October1st to 15thDay
18%414323335%48%
1818
16th to endDay
13%424422335%52%
1920
November1st to 15thDay
12%4244345%45%49%
1865
16th to endDay
13%5%245%2435%6%47%
1755
December1st to 15thDay
11%6%25%5%35%45%7%42%
1632
16th to endDay
17%6%25%5%2445%6%38%
1728
January1st to 15thNight
12%5%24434446%48%
2327
16th to endNight
11%6%35%3345%5%6%44%
2496
February1st to 15thNight
12%6%24434447%45%
2285
16th to endNight
9%5%346%25%5%5%7%44%
1863
March1st to 15thNight
14%425%335%447%44%
1968
16th to endNight
15%5%24435%45%6%41%
2112
April1st to 15thNight
11%5%2442445%8%45%
1885
16th to endNight
16%315%42346%7%43%
1722
May1st to 15thNight
14%6%35%5%36%45%7%38%
1620
16th to endNight
11%5%24425%5%7%9%41%
1682
June1st to 15thNight
8%424425%6%7%11%41%
1620
16th to endNight
7%32443448%10%46%
1620
July1st to 15thNight
8%424435%6%7%10%41%
1620
16th to endNight
43146%46%5%9%14%39%
1703
August1st to 15thNight
13%5%26%4345%6%9%38%
1620
16th to endNight
9%315%6%45%5%6%11%37%
1817
September1st to 15thNight
11%6%25%42445%6%45%
1902
16th to endNight
17%7%245%34446%38%
1980
October1st to 15thNight
16%424423345%47%
2141
16th to endNight
11%313423335%55%
2304
November1st to 15thNight
14%5%23323435%51%
2320
16th to endNight
13%41332345%6%51%
2535
December1st to 15thNight
12%5%26%5%34445%43%
2365
16th to endNight
15%7%26%6%25%5%6%7%36%
2496

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
12%7%35%43446%7%40%
1611
16th to endDay
12%6%25%5%3446%5%43%
1728
February1st to 15thDay
11%6%35%6%4346%6%42%
1575
16th to endDay
12%5%35%5%26%45%8%40%
1608
March1st to 15thDay
13%5%24335%5%5%7%44%
1980
16th to endDay
17%7%35%5%35%35%5%37%
2111
April1st to 15thDay
10%42443345%9%46%
2062
16th to endDay
15%6%36%6%34447%37%
2249
May1st to 15thDay
18%5%36%6%45%5%5%6%31%
2331
16th to endDay
12%5%26%6%36%6%6%8%33%
2431
June1st to 15thDay
10%5%36%6%46%7%7%9%31%
2340
16th to endDay
8%5%26%6%47%6%8%9%35%
2340
July1st to 15thDay
11%5%46%8%5%7%6%8%9%26%
2340
16th to endDay
9%6%37%9%5%7%8%7%9%25%
2465
August1st to 15thDay
13%6%37%7%47%7%7%9%25%
2340
16th to endDay
12%6%26%6%46%7%7%10%29%
2372
September1st to 15thDay
15%6%25%6%345%5%7%37%
2055
16th to endDay
23%6%346%24446%32%
1980
October1st to 15thDay
18%413423336%47%
1818
16th to endDay
13%414423335%51%
1920
November1st to 15thDay
11%4244345%46%49%
1865
16th to endDay
13%5%2442335%6%47%
1755
December1st to 15thDay
11%6%25%5%35%45%7%41%
1632
16th to endDay
16%7%25%5%245%46%38%
1728
January1st to 15thNight
12%424434446%47%
2327
16th to endNight
11%6%34325%5%5%6%44%
2496
February1st to 15thNight
12%5%3443445%6%46%
2278
16th to endNight
9%5%346%35%45%7%43%
1863
March1st to 15thNight
13%424335%45%7%44%
1980
16th to endNight
15%4245%35%5%5%6%41%
2112
April1st to 15thNight
11%5%2442445%8%45%
1885
16th to endNight
15%315%5%235%5%7%43%
1722
May1st to 15thNight
14%5%35%5%35%45%7%37%
1619
16th to endNight
12%5%14435%5%7%9%40%
1682
June1st to 15thNight
8%5%24435%5%7%10%41%
1620
16th to endNight
7%41443448%9%46%
1620
July1st to 15thNight
8%425%335%6%8%10%41%
1620
16th to endNight
43146%46%6%9%13%38%
1703
August1st to 15thNight
13%5%26%5%245%7%9%38%
1620
16th to endNight
9%315%6%45%5%7%10%38%
1817
September1st to 15thNight
11%6%25%4345%5%6%45%
1902
16th to endNight
17%7%25%5%35%346%38%
1980
October1st to 15thNight
16%5%24423346%47%
2141
16th to endNight
11%313423335%55%
2304
November1st to 15thNight
14%5%23323335%50%
2320
16th to endNight
13%41331345%6%51%
2535
December1st to 15thNight
12%6%26%5%25%45%5%43%
2365
16th to endNight
15%7%36%4345%5%7%36%
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
40%49%23%17%4
1612
16th to endDay
40%27%26%17%5%
1728
February1st to 15thDay
40%29%23%19%3
1577
16th to endDay
41%312%23%17%3
1608
March1st to 15thDay
38%310%24%18%5%
1980
16th to endDay
46%48%22%14%3
2112
April1st to 15thDay
32%314%26%16%7%
2062
16th to endDay
46%39%20%15%4
2249
May1st to 15thDay
50%415%17%10%2
2331
16th to endDay
45%5%15%23%8%1
2435
June1st to 15thDay
43%6%17%21%10%
2340
16th to endDay
42%7%15%20%12%2
2340
July1st to 15thDay
49%7%15%15%11%1
2201
16th to endDay
48%7%17%16%9%
2310
August1st to 15thDay
50%7%13%18%9%
2327
16th to endDay
46%6%15%19%9%1
2372
September1st to 15thDay
43%410%20%17%2
2055
16th to endDay
51%37%20%16%1
1980
October1st to 15thDay
37%38%25%19%5%
1818
16th to endDay
34%26%27%22%7%
1920
November1st to 15thDay
34%29%18%27%7%
1865
16th to endDay
36%26%24%25%4
1755
December1st to 15thDay
40%310%20%19%6%
1632
16th to endDay
45%310%19%17%3
1728
January1st to 15thNight
37%211%19%21%7%
2327
16th to endNight
38%210%24%19%4
2496
February1st to 15thNight
38%17%26%20%5%
2287
16th to endNight
38%310%27%17%2
1863
March1st to 15thNight
37%5%8%27%16%4
1980
16th to endNight
41%411%23%16%2
2112
April1st to 15thNight
37%312%24%18%5%
1885
16th to endNight
38%312%22%17%5%
1722
May1st to 15thNight
45%5%14%22%12%1
1620
16th to endNight
37%5%21%24%9%1
1684
June1st to 15thNight
35%7%20%25%10%
1620
16th to endNight
30%8%18%25%15%2
1620
July1st to 15thNight
36%7%19%21%11%4
1530
16th to endNight
32%6%21%26%11%1
1595
August1st to 15thNight
41%5%16%20%14%1
1609
16th to endNight
38%6%17%24%11%1
1817
September1st to 15thNight
38%5%12%22%16%4
1902
16th to endNight
47%38%19%19%1
1980
October1st to 15thNight
39%37%25%21%3
2141
16th to endNight
31%25%28%24%7%
2304
November1st to 15thNight
35%28%20%23%9%
2320
16th to endNight
32%37%25%26%5%
2535
December1st to 15thNight
41%37%22%18%5%
2365
16th to endNight
46%29%19%18%3
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
26%33%24%12%3
90
16th to endDay
33%36%21%7%1
96
February1st to 15thDay
21%38%34%5%
90
16th to endDay
26%35%20%15%1
120
March1st to 15thDay
21%26%27%18%6%
270
16th to endDay
21%25%28%16%6%1
288
April1st to 15thDay
17%21%26%20%12%1
270
16th to endDay
20%9%27%23%13%5%
270
May1st to 15thDay
29%17%25%12%8%7%
288
16th to endDay
15%8%22%21%22%10%
331
June1st to 15thDay
12%7%19%28%20%12%
315
16th to endDay
11%8%24%27%19%8%
315
July1st to 15thDay
15%422%31%15%10%
305
16th to endDay
8%312%28%27%18%
326
August1st to 15thDay
15%6%15%23%22%16%
313
16th to endDay
13%311%23%23%24%
332
September1st to 15thDay
17%6%13%16%26%19%
315
16th to endDay
22%416%23%20%12%
314
October1st to 15thDay
21%8%14%25%20%7%
315
16th to endDay
15%19%23%20%15%5%
336
November1st to 15thDay
24%16%18%23%15%2
283
16th to endDay
20%25%21%23%8%1
135
December1st to 15thDay
19%34%26%17%21
94
16th to endDay
42%17%25%13%1
96
January1st to 15thNight
22%28%28%15%4
720
16th to endNight
21%27%31%18%1
768
February1st to 15thNight
23%26%29%19%1
704
16th to endNight
19%30%29%19%1
631
March1st to 15thNight
20%21%29%22%4
720
16th to endNight
21%19%30%19%8%
768
April1st to 15thNight
22%19%28%22%7%
718
16th to endNight
19%11%27%26%12%1
642
May1st to 15thNight
18%12%25%27%16%
540
16th to endNight
14%5%18%26%27%8%
563
June1st to 15thNight
11%215%33%31%5%
540
16th to endNight
8%213%35%32%5%
540
July1st to 15thNight
12%110%34%34%4
510
16th to endNight
5%19%31%41%10%
564
August1st to 15thNight
14%18%35%33%5%
539
16th to endNight
10%28%26%42%9%
671
September1st to 15thNight
14%39%30%34%7%
720
16th to endNight
22%5%12%25%28%5%
717
October1st to 15thNight
20%10%16%23%23%6%
720
16th to endNight
15%15%26%23%16%2
768
November1st to 15thNight
19%14%22%26%14%3
760
16th to endNight
19%21%21%23%13%1
780
December1st to 15thNight
19%22%23%26%8%
728
16th to endNight
23%24%25%21%5%
768
Page generated at 2017-12-03 11:16:40. Version ac04

Copyright 2017 A. Danko


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