DeRidder
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the DeRidder 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
50%
15469
23%
47070
17%
15423
57%
15423
30%
28614

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
31%
900
23%
2327
10%
895
39%
895
27%
1537
January16th to endNight
31%
960
24%
2496
10%
960
39%
960
27%
1671
February1st to 15thNight
29%
833
24%
2240
8%
830
38%
830
27%
1477
February16th to endNight
27%
506
25%
1768
12%
506
39%
506
20%
1116
March1st to 15thNight
31%
540
24%
1980
15%
540
42%
540
20%
1239
March16th to endNight
40%
576
22%
2112
17%
576
50%
576
27%
1199
April1st to 15thNight
36%
539
23%
1848
14%
539
49%
539
28%
1082
April16th to endNight
42%
540
22%
1800
17%
540
52%
540
27%
1077
May1st to 15thNight
41%
539
17%
1800
13%
539
50%
539
26%
1104
May16th to endNight
59%
563
23%
1717
22%
561
64%
561
35%
992
June1st to 15thNight
79%
540
19%
1620
20%
540
81%
540
42%
886
June16th to endNight
74%
540
16%
1620
17%
540
76%
540
32%
993
July1st to 15thNight
79%
510
15%
1530
18%
510
79%
510
33%
921
July16th to endNight
79%
564
17%
1594
20%
531
81%
531
32%
970
August1st to 15thNight
84%
539
20%
1700
24%
536
84%
536
43%
891
August16th to endNight
70%
573
13%
1910
17%
573
70%
573
21%
1309
September1st to 15thNight
72%
540
20%
1806
22%
540
72%
540
31%
1059
September16th to endNight
70%
563
28%
2006
30%
563
73%
563
31%
1112
October1st to 15thNight
67%
684
29%
2052
24%
684
69%
684
41%
1110
October16th to endNight
58%
704
36%
2112
26%
704
66%
704
42%
1134
November1st to 15thNight
52%
700
29%
2100
21%
700
58%
700
35%
1184
November16th to endNight
45%
720
32%
2160
22%
720
54%
720
34%
1249
December1st to 15thNight
37%
836
25%
2276
14%
836
43%
836
25%
1543
December16th to endNight
32%
960
19%
2496
9%
960
38%
960
23%
1759

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%6%35%6%35%5%5%7%37%
48114
Night
12%5%2442445%8%46%
47268
TransparencyDay
44%6%10%16%15%6%
47815
Night
35%5%12%19%17%8%
47072
SeeingDay
12%5%16%25%27%12%
5521
Night
14%6%21%29%22%3
15470

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
19%6%2432235%5%43%
1611
16th to endDay
22%5%35%423335%40%
1728
February1st to 15thDay
17%6%35%413445%42%
1618
16th to endDay
20%7%25%422445%39%
1714
March1st to 15thDay
23%7%25%5%24335%37%
1980
16th to endDay
13%7%35%6%34346%40%
2110
April1st to 15thDay
14%6%345%345%5%7%39%
2099
16th to endDay
14%5%25%6%35%5%6%8%35%
2160
May1st to 15thDay
13%7%36%6%35%47%8%34%
2151
16th to endDay
8%5%35%7%5%6%6%7%10%32%
2394
June1st to 15thDay
8%426%7%5%6%7%8%10%31%
2340
16th to endDay
7%6%36%9%5%9%8%8%10%26%
2340
July1st to 15thDay
10%5%36%7%5%8%8%7%11%26%
2340
16th to endDay
9%5%37%8%5%8%7%7%9%26%
2466
August1st to 15thDay
6%325%6%5%7%7%8%11%34%
2248
16th to endDay
13%5%36%9%47%7%6%8%27%
2292
September1st to 15thDay
13%6%25%6%345%6%7%38%
2149
16th to endDay
9%425%5%46%5%6%7%40%
1941
October1st to 15thDay
8%4245%245%46%52%
1706
16th to endDay
12%312323446%55%
1760
November1st to 15thDay
11%6%25%5%2435%6%46%
1758
16th to endDay
15%6%24423335%48%
1800
December1st to 15thDay
19%8%34423446%38%
1681
16th to endDay
22%8%345%23335%35%
1728
January1st to 15thNight
18%6%24323246%44%
2327
16th to endNight
19%7%14323335%44%
2496
February1st to 15thNight
16%6%24423445%45%
2232
16th to endNight
19%6%24313335%43%
1768
March1st to 15thNight
19%6%24323335%43%
1980
16th to endNight
10%5%2343345%8%47%
2112
April1st to 15thNight
12%5%24424449%45%
1848
16th to endNight
13%424425%46%7%45%
1800
May1st to 15thNight
9%5%346%25%5%6%9%42%
1799
16th to endNight
8%42432345%9%50%
1716
June1st to 15thNight
331342446%10%55%
1620
16th to endNight
5%224445%6%8%12%42%
1620
July1st to 15thNight
5%423425%6%7%11%46%
1620
16th to endNight
5%323426%6%9%13%41%
1702
August1st to 15thNight
42132245%8%13%52%
1710
16th to endNight
10%4245%46%7%8%10%34%
1910
September1st to 15thNight
10%3234145%6%9%47%
1806
16th to endNight
8%425%42435%6%51%
2006
October1st to 15thNight
7%31332445%8%56%
2052
16th to endNight
11%312312235%61%
2112
November1st to 15thNight
8%423423448%53%
2100
16th to endNight
13%5%23313335%54%
2160
December1st to 15thNight
17%7%25%424346%40%
2276
16th to endNight
19%9%34323445%37%
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
42%25%16%21%11%
1612
16th to endDay
47%25%13%17%12%
1728
February1st to 15thDay
45%35%15%20%9%
1620
16th to endDay
47%46%13%18%9%
1714
March1st to 15thDay
50%37%13%18%7%
1980
16th to endDay
45%47%15%23%5%
2112
April1st to 15thDay
42%5%8%17%17%8%
2099
16th to endDay
45%5%9%16%16%5%
2160
May1st to 15thDay
46%6%10%15%13%7%
2151
16th to endDay
43%8%13%19%13%1
2398
June1st to 15thDay
45%8%12%18%13%
2340
16th to endDay
47%11%14%16%8%
2340
July1st to 15thDay
48%10%14%18%7%
2201
16th to endDay
49%10%17%18%4
2311
August1st to 15thDay
37%11%18%23%8%
2234
16th to endDay
50%12%14%14%6%1
2292
September1st to 15thDay
43%8%14%16%12%4
2149
16th to endDay
40%6%11%17%17%5%
1941
October1st to 15thDay
33%5%7%16%21%15%
1706
16th to endDay
29%4414%31%15%
1760
November1st to 15thDay
38%37%16%24%9%
1758
16th to endDay
39%36%10%27%12%
1800
December1st to 15thDay
47%37%19%15%6%
1681
16th to endDay
53%35%14%18%5%
1728
January1st to 15thNight
42%26%14%22%12%
2327
16th to endNight
43%36%14%19%12%
2496
February1st to 15thNight
42%35%16%20%12%
2241
16th to endNight
44%3416%18%12%
1768
March1st to 15thNight
44%37%14%18%10%
1980
16th to endNight
34%5%12%17%21%7%
2112
April1st to 15thNight
36%412%20%15%11%
1848
16th to endNight
36%5%12%19%16%9%
1800
May1st to 15thNight
39%5%14%16%16%8%
1800
16th to endNight
30%6%17%26%17%2
1718
June1st to 15thNight
23%8%18%31%16%1
1620
16th to endNight
30%10%22%23%11%
1620
July1st to 15thNight
27%12%29%21%8%
1530
16th to endNight
27%13%27%24%6%
1594
August1st to 15thNight
20%9%29%30%10%
1700
16th to endNight
39%14%21%15%7%1
1910
September1st to 15thNight
31%8%19%22%11%6%
1806
16th to endNight
31%5%13%19%20%8%
2006
October1st to 15thNight
26%411%19%21%16%
2052
16th to endNight
27%3315%28%21%
2112
November1st to 15thNight
30%5%10%19%24%9%
2100
16th to endNight
34%26%12%26%16%
2160
December1st to 15thNight
46%27%20%15%7%
2276
16th to endNight
48%35%15%18%8%
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
30%10%35%16%7%
90
16th to endDay
21%26%36%9%6%
96
February1st to 15thDay
16%18%33%27%3
90
16th to endDay
23%16%39%19%1
81
March1st to 15thDay
35%18%33%6%5%
90
16th to endDay
18%17%25%25%12%1
96
April1st to 15thDay
17%13%27%24%15%
218
16th to endDay
22%8%22%25%18%2
270
May1st to 15thDay
19%6%27%26%18%2
288
16th to endDay
8%6%26%31%19%7%
481
June1st to 15thDay
7%110%37%32%10%
495
16th to endDay
8%311%27%33%15%
495
July1st to 15thDay
6%8%29%34%19%
475
16th to endDay
6%5%19%45%23%
515
August1st to 15thDay
6%417%48%23%
401
16th to endDay
18%415%32%29%
332
September1st to 15thDay
8%16%25%37%20%
304
16th to endDay
5%439%33%16%
135
October1st to 15thDay
318%38%30%7%
107
16th to endDay
21%5%15%23%21%11%
96
November1st to 15thDay
15%5%36%27%14%
90
16th to endDay
22%11%34%22%10%
90
December1st to 15thDay
25%7%32%21%10%3
90
16th to endDay
27%21%32%15%3
96
January1st to 15thNight
23%12%29%26%8%
900
16th to endNight
23%10%30%28%6%
960
February1st to 15thNight
21%12%34%25%6%
833
16th to endNight
25%11%33%26%3
506
March1st to 15thNight
21%12%30%29%5%
540
16th to endNight
13%9%32%32%10%
576
April1st to 15thNight
12%12%35%29%9%
539
16th to endNight
14%8%31%30%14%
540
May1st to 15thNight
11%7%35%29%14%1
540
16th to endNight
8%322%36%26%3
563
June1st to 15thNight
47%42%38%5%
540
16th to endNight
6%8%32%42%8%
540
July1st to 15thNight
41336%40%13%
510
16th to endNight
5%1323%52%14%
564
August1st to 15thNight
4327%51%13%
539
16th to endNight
11%5%22%46%14%
573
September1st to 15thNight
12%6%26%44%9%
540
16th to endNight
9%9%25%46%7%
563
October1st to 15thNight
9%116%30%38%3
684
16th to endNight
11%420%33%25%2
704
November1st to 15thNight
10%6%25%34%20%2
700
16th to endNight
15%8%26%31%15%1
720
December1st to 15thNight
22%11%24%29%11%
836
16th to endNight
27%10%27%27%7%
960
Page generated at 2017-10-07 13:07:45. Version ac04

Copyright 2017 A. Danko


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