Otter Point
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Otter Point clear sky chart from 2005-11-05 to 2017-09-17.

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
45%
14536
9%
46734
8%
14511
47%
14511
16%
34342

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
33%
746
7%
2686
6%
746
36%
746
8%
2211
January16th to endNight
36%
780
7%
2700
6%
780
38%
780
9%
2171
February1st to 15thNight
32%
696
6%
2288
4%
696
35%
696
8%
1890
February16th to endNight
35%
632
10%
2053
8%
632
38%
632
12%
1589
March1st to 15thNight
31%
720
6%
2032
4%
720
32%
720
10%
1687
March16th to endNight
31%
768
6%
2097
4%
768
32%
768
12%
1725
April1st to 15thNight
41%
701
7%
1781
4%
701
42%
701
16%
1399
April16th to endNight
43%
540
10%
1620
7%
540
45%
540
17%
1193
May1st to 15thNight
53%
362
10%
1442
17%
362
53%
362
17%
949
May16th to endNight
60%
375
7%
1463
10%
374
61%
374
17%
976
June1st to 15thNight
54%
360
5%
1260
5%
360
54%
360
21%
822
June16th to endNight
57%
360
6%
1260
5%
360
58%
360
25%
803
July1st to 15thNight
72%
340
11%
1190
11%
340
72%
340
38%
617
July16th to endNight
81%
376
15%
1326
22%
354
85%
354
42%
619
August1st to 15thNight
81%
481
15%
1555
18%
479
81%
479
39%
799
August16th to endNight
74%
600
20%
1746
17%
600
75%
600
39%
956
September1st to 15thNight
77%
720
21%
1800
13%
720
78%
720
47%
1054
September16th to endNight
56%
664
17%
1842
14%
664
57%
664
26%
1244
October1st to 15thNight
51%
660
10%
1980
11%
660
52%
660
21%
1390
October16th to endNight
40%
704
8%
2179
7%
704
42%
704
14%
1680
November1st to 15thNight
26%
700
6%
2450
5%
700
29%
700
8%
2017
November16th to endNight
30%
720
6%
2520
4%
720
32%
720
8%
2076
December1st to 15thNight
32%
731
6%
2584
4%
731
36%
731
9%
2077
December16th to endNight
22%
800
5%
2880
3%
800
24%
800
7%
2398

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
15%8%37%6%35%5%5%6%31%
48076
Night
18%8%47%6%35%5%5%6%27%
46888
Cloud CoverDay
15%8%36%5%35%5%5%7%32%
48076
Night
18%8%36%5%35%5%5%7%29%
46891
TransparencyDay
48%10%16%17%5%
47733
Night
51%9%15%15%6%1
46735
SeeingDay
16%320%30%22%6%
6212
Night
20%419%28%20%6%
14549

By Month

Percentage Cloud Cover NW (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%14%6%9%7%25%34416%
1253
16th to endDay
25%12%6%9%9%35%46%5%11%
1521
February1st to 15thDay
27%13%5%9%7%35%5%5%5%13%
1576
16th to endDay
17%9%49%7%45%6%6%5%21%
1421
March1st to 15thDay
23%12%6%10%8%445%45%14%
1925
16th to endDay
20%11%5%10%9%36%45%415%
2127
April1st to 15thDay
17%9%48%8%46%6%6%8%19%
2166
16th to endDay
15%9%38%7%45%5%7%7%23%
2340
May1st to 15thDay
13%7%36%7%35%5%5%7%33%
2508
16th to endDay
12%6%36%7%47%5%7%8%28%
2646
June1st to 15thDay
10%7%47%7%35%5%6%7%33%
2700
16th to endDay
10%6%36%8%5%5%5%5%7%35%
2700
July1st to 15thDay
6%3245%2445%7%53%
2700
16th to endDay
5%21332435%9%58%
2751
August1st to 15thDay
5%213425%46%8%54%
2396
16th to endDay
6%425%5%345%5%9%46%
2456
September1st to 15thDay
7%3245%245%5%7%50%
2160
16th to endDay
16%6%45%6%34446%36%
1822
October1st to 15thDay
18%8%47%5%35%5%5%7%27%
1650
16th to endDay
22%9%48%8%45%6%6%7%17%
1692
November1st to 15thDay
29%11%48%6%45%44416%
1408
16th to endDay
26%12%5%9%5%45%5%5%416%
1440
December1st to 15thDay
22%12%5%9%6%35%44420%
1374
16th to endDay
24%15%7%10%6%3335%414%
1344
January1st to 15thNight
26%11%5%7%6%35%445%19%
2686
16th to endNight
26%8%5%7%7%345%5%6%18%
2700
February1st to 15thNight
25%11%5%8%6%4444418%
2276
16th to endNight
20%10%48%7%35%446%24%
2053
March1st to 15thNight
24%12%5%9%6%36%45%416%
2032
16th to endNight
20%9%7%11%8%35%45%5%16%
2093
April1st to 15thNight
17%9%46%7%5%5%6%5%6%23%
1781
16th to endNight
17%8%37%7%35%5%7%8%25%
1620
May1st to 15thNight
13%5%37%7%36%5%6%7%33%
1442
16th to endNight
10%5%37%7%46%6%7%10%28%
1463
June1st to 15thNight
10%7%5%7%7%5%6%7%6%6%30%
1260
16th to endNight
8%7%26%7%46%5%7%10%33%
1260
July1st to 15thNight
5%4246%45%5%5%9%47%
1260
16th to endNight
31135%36%6%6%12%50%
1418
August1st to 15thNight
23145%246%7%11%49%
1563
16th to endNight
5%3246%345%7%10%45%
1746
September1st to 15thNight
6%313434447%56%
1800
16th to endNight
14%6%37%6%2446%7%35%
1842
October1st to 15thNight
17%7%36%7%34445%35%
1980
16th to endNight
25%8%38%6%35%46%6%21%
2179
November1st to 15thNight
30%10%5%8%6%45%42318%
2450
16th to endNight
24%10%5%10%7%35%5%3418%
2520
December1st to 15thNight
23%11%5%8%6%35%45%5%20%
2584
16th to endNight
25%13%6%9%7%345%4416%
2880

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
25%16%5%8%5%25%5%3416%
1253
16th to endDay
24%14%5%8%7%46%5%5%6%11%
1521
February1st to 15thDay
28%13%38%6%36%6%5%5%13%
1576
16th to endDay
16%12%5%7%6%45%6%5%6%21%
1421
March1st to 15thDay
22%13%7%8%6%45%5%5%6%14%
1925
16th to endDay
20%12%5%9%7%46%5%46%15%
2127
April1st to 15thDay
16%10%47%7%5%6%6%7%7%20%
2166
16th to endDay
15%9%46%7%45%6%7%7%25%
2340
May1st to 15thDay
12%7%27%6%46%5%5%6%34%
2508
16th to endDay
13%6%36%6%46%5%6%9%30%
2646
June1st to 15thDay
10%6%27%6%35%6%6%8%36%
2700
16th to endDay
10%6%25%6%36%6%5%7%37%
2700
July1st to 15thDay
6%41432445%7%56%
2700
16th to endDay
5%21222335%8%63%
2751
August1st to 15thDay
5%313313449%58%
2396
16th to endDay
6%315%4335%6%9%49%
2456
September1st to 15thDay
6%32442335%8%53%
2160
16th to endDay
16%6%25%5%245%5%8%36%
1822
October1st to 15thDay
18%9%36%6%36%46%6%27%
1650
16th to endDay
22%9%46%7%5%6%6%5%8%17%
1692
November1st to 15thDay
31%11%48%5%345%4416%
1408
16th to endDay
26%11%7%6%5%45%5%4416%
1440
December1st to 15thDay
24%13%47%5%35%45%5%20%
1374
16th to endDay
24%17%6%10%6%24345%14%
1344
January1st to 15thNight
27%10%47%5%35%45%5%20%
2685
16th to endNight
25%10%37%6%36%5%5%7%18%
2700
February1st to 15thNight
25%10%49%7%345%35%19%
2276
16th to endNight
21%10%46%6%36%446%24%
2053
March1st to 15thNight
25%12%47%6%45%5%5%5%17%
2032
16th to endNight
19%11%5%9%8%36%5%5%5%19%
2097
April1st to 15thNight
16%10%37%5%36%5%7%7%25%
1781
16th to endNight
18%6%28%5%346%7%9%27%
1620
May1st to 15thNight
11%5%36%7%35%5%5%7%36%
1442
16th to endNight
9%5%36%6%47%6%7%9%32%
1463
June1st to 15thNight
10%7%28%5%35%5%8%8%33%
1260
16th to endNight
8%6%25%6%46%49%9%37%
1260
July1st to 15thNight
44135%2446%10%51%
1260
16th to endNight
211232347%11%58%
1418
August1st to 15thNight
211342346%9%58%
1563
16th to endNight
6%3124245%7%10%51%
1746
September1st to 15thNight
6%21321346%8%59%
1800
16th to endNight
14%7%27%5%245%6%7%37%
1842
October1st to 15thNight
17%8%36%5%35%435%36%
1980
16th to endNight
25%8%37%5%35%46%6%22%
2179
November1st to 15thNight
31%10%47%6%35%43418%
2450
16th to endNight
23%11%5%9%6%35%45%5%19%
2520
December1st to 15thNight
23%12%47%5%35%5%46%21%
2584
16th to endNight
24%14%5%8%6%35%446%17%
2880

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
70%9%7%8%4
1253
16th to endDay
74%7%9%7%1
1521
February1st to 15thDay
70%10%8%6%3
1576
16th to endDay
61%9%12%12%3
1421
March1st to 15thDay
67%8%11%10%1
1925
16th to endDay
66%9%12%10%
2127
April1st to 15thDay
56%13%14%13%2
2166
16th to endDay
52%12%13%17%3
2340
May1st to 15thDay
44%11%17%19%7%
2508
16th to endDay
46%12%22%15%2
2650
June1st to 15thDay
41%14%21%16%6%
2700
16th to endDay
40%13%21%18%4
2700
July1st to 15thDay
25%10%20%29%12%2
2541
16th to endDay
18%10%25%31%12%1
2580
August1st to 15thDay
24%9%22%31%9%2
2379
16th to endDay
29%10%23%27%7%1
2456
September1st to 15thDay
28%10%17%25%17%1
2160
16th to endDay
45%10%15%18%8%
1822
October1st to 15thDay
53%10%14%16%6%
1650
16th to endDay
61%10%14%9%3
1692
November1st to 15thDay
68%8%10%8%21
1408
16th to endDay
69%9%7%10%3
1440
December1st to 15thDay
66%7%11%11%3
1374
16th to endDay
71%7%8%8%2
1344
January1st to 15thNight
63%11%10%9%5%
2686
16th to endNight
63%9%10%12%31
2700
February1st to 15thNight
65%9%10%9%4
2288
16th to endNight
58%8%13%14%4
2053
March1st to 15thNight
64%9%11%12%2
2032
16th to endNight
62%9%14%11%1
2097
April1st to 15thNight
54%11%15%15%3
1781
16th to endNight
49%11%17%16%5%
1620
May1st to 15thNight
41%12%17%17%9%1
1443
16th to endNight
39%15%22%17%4
1463
June1st to 15thNight
40%10%24%18%5%1
1260
16th to endNight
35%11%25%21%31
1260
July1st to 15thNight
23%7%19%30%14%3
1190
16th to endNight
15%11%23%30%16%2
1326
August1st to 15thNight
19%11%23%28%13%3
1555
16th to endNight
24%8%22%32%9%2
1746
September1st to 15thNight
22%8%18%23%20%6%
1800
16th to endNight
41%7%15%20%12%2
1842
October1st to 15thNight
49%5%16%18%8%1
1980
16th to endNight
58%7%16%13%4
2179
November1st to 15thNight
66%8%11%9%21
2450
16th to endNight
64%10%9%8%5%
2520
December1st to 15thNight
64%7%13%10%3
2584
16th to endNight
67%8%11%7%3
2880

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
11%11%23%35%16%1
60
16th to endDay
33%6%24%24%8%2
124
February1st to 15thDay
36%7%22%26%6%
236
16th to endDay
20%9%25%26%15%2
211
March1st to 15thDay
34%6%31%18%7%1
270
16th to endDay
23%8%31%25%8%2
288
April1st to 15thDay
21%6%22%26%18%4
269
16th to endDay
18%5%24%35%12%3
270
May1st to 15thDay
18%5%20%26%26%2
288
16th to endDay
11%116%32%29%8%
361
June1st to 15thDay
8%225%35%23%4
495
16th to endDay
10%326%34%19%6%
495
July1st to 15thDay
6%115%36%33%6%
475
16th to endDay
3112%36%33%13%
420
August1st to 15thDay
49%33%32%20%
315
16th to endDay
6%110%30%32%18%
332
September1st to 15thDay
8%111%31%33%14%
315
16th to endDay
16%116%30%28%6%
260
October1st to 15thDay
25%418%29%20%3
255
16th to endDay
25%423%27%16%3
229
November1st to 15thDay
41%5%25%21%6%
60
16th to endDay
28%321%20%21%5%
60
December1st to 15thDay
28%6%36%26%1
60
16th to endDay
39%6%28%21%4
64
January1st to 15thNight
27%9%20%28%12%
750
16th to endNight
28%417%27%19%2
780
February1st to 15thNight
25%8%21%26%14%2
704
16th to endNight
24%6%21%28%14%4
632
March1st to 15thNight
28%424%24%12%4
720
16th to endNight
20%6%26%28%14%3
768
April1st to 15thNight
19%322%28%20%4
701
16th to endNight
19%323%33%17%3
540
May1st to 15thNight
14%318%31%23%8%
363
16th to endNight
11%113%36%31%5%
375
June1st to 15thNight
12%121%33%27%4
360
16th to endNight
9%123%33%24%7%
360
July1st to 15thNight
5%113%33%37%9%
340
16th to endNight
28%36%38%13%
376
August1st to 15thNight
36%26%44%19%
481
16th to endNight
6%12%30%35%15%
600
September1st to 15thNight
7%8%25%35%22%
720
16th to endNight
15%114%30%25%12%
664
October1st to 15thNight
21%114%26%25%10%
660
16th to endNight
27%315%27%18%7%
704
November1st to 15thNight
33%6%24%24%10%
700
16th to endNight
25%6%26%26%13%2
720
December1st to 15thNight
29%6%22%26%14%
731
16th to endNight
27%7%28%26%9%
800
Page generated at 2017-09-18 05:38:18. Version ac04

Copyright 2017 A. Danko


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