Cullman County Rd
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cullman County Rd clear sky chart from 2005-11-05 to 2017-09-23.

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%
15245
25%
47040
18%
15202
57%
15202
30%
28119

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
26%
720
24%
2327
11%
716
43%
716
22%
1456
January16th to endNight
26%
768
27%
2310
13%
768
40%
768
22%
1496
February1st to 15thNight
30%
704
25%
2112
11%
701
44%
701
27%
1308
February16th to endNight
30%
631
26%
1893
13%
631
41%
631
26%
1194
March1st to 15thNight
31%
720
21%
2160
12%
720
39%
720
25%
1357
March16th to endNight
39%
689
24%
2037
15%
689
47%
689
30%
1222
April1st to 15thNight
42%
539
25%
1797
18%
539
53%
539
32%
1010
April16th to endNight
48%
540
28%
1800
23%
540
58%
540
34%
979
May1st to 15thNight
53%
540
22%
1648
14%
540
61%
540
31%
1004
May16th to endNight
70%
561
25%
1682
20%
561
73%
561
39%
945
June1st to 15thNight
73%
540
19%
1620
16%
540
75%
540
37%
921
June16th to endNight
75%
540
21%
1620
19%
540
76%
540
38%
932
July1st to 15thNight
73%
510
14%
1530
13%
510
74%
510
31%
949
July16th to endNight
73%
564
17%
1631
17%
531
75%
531
32%
992
August1st to 15thNight
81%
539
19%
1788
23%
536
82%
536
35%
1005
August16th to endNight
70%
573
21%
1910
26%
573
70%
573
27%
1184
September1st to 15thNight
64%
606
21%
1866
20%
606
67%
606
29%
1168
September16th to endNight
66%
689
29%
1903
24%
689
68%
689
39%
1109
October1st to 15thNight
58%
660
35%
1815
27%
660
63%
660
41%
1037
October16th to endNight
53%
704
34%
2139
29%
704
61%
704
36%
1190
November1st to 15thNight
49%
700
31%
2276
25%
700
60%
700
36%
1214
November16th to endNight
39%
720
28%
2340
19%
720
52%
720
28%
1356
December1st to 15thNight
37%
720
23%
2340
16%
720
47%
720
24%
1451
December16th to endNight
30%
768
22%
2496
15%
768
40%
768
20%
1640

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%5%7%41%
47855
Night
12%42442445%7%46%
47243
TransparencyDay
40%310%21%18%4
47560
Night
36%310%21%21%6%
47042
SeeingDay
16%5%17%23%22%14%
5157
Night
15%6%20%29%23%5%
15247

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
22%6%2442323442%
1611
16th to endDay
19%6%33323335%46%
1911
February1st to 15thDay
19%8%34423445%42%
1750
16th to endDay
19%6%34313445%42%
1580
March1st to 15thDay
19%6%45%434336%39%
1800
16th to endDay
14%6%36%43345%7%40%
2194
April1st to 15thDay
12%5%2442345%6%46%
2151
16th to endDay
10%425%6%245%5%8%45%
2160
May1st to 15thDay
12%5%245%35%448%41%
2301
16th to endDay
9%425%6%45%5%5%7%41%
2431
June1st to 15thDay
7%415%5%48%7%7%9%37%
2340
16th to endDay
6%3245%36%6%7%9%43%
2340
July1st to 15thDay
9%426%7%47%7%6%12%31%
2340
16th to endDay
6%425%6%48%9%8%11%31%
2423
August1st to 15thDay
7%316%6%5%7%6%9%10%34%
2160
16th to endDay
11%6%36%7%46%6%7%9%30%
2292
September1st to 15thDay
13%435%6%45%5%5%8%37%
2081
16th to endDay
12%5%1442446%6%46%
1894
October1st to 15thDay
10%41442445%7%49%
1815
16th to endDay
12%41422333458%
1731
November1st to 15thDay
13%413423245%55%
1582
16th to endDay
17%413313446%48%
1620
December1st to 15thDay
20%7%25%314445%39%
1620
16th to endDay
25%7%35%324235%36%
1728
January1st to 15thNight
18%6%24423335%43%
2327
16th to endNight
17%7%245%23445%41%
2310
February1st to 15thNight
18%5%24323335%47%
2103
16th to endNight
17%5%24333345%46%
1893
March1st to 15thNight
18%5%24423346%43%
2160
16th to endNight
12%5%25%423446%48%
2037
April1st to 15thNight
12%423324448%48%
1797
16th to endNight
10%31432345%7%52%
1800
May1st to 15thNight
10%425%5%35%45%7%46%
1647
16th to endNight
5%32444446%9%49%
1682
June1st to 15thNight
5%213436%6%6%10%47%
1620
16th to endNight
422443447%11%48%
1620
July1st to 15thNight
7%335%5%46%7%6%8%41%
1620
16th to endNight
5%4246%37%6%6%12%39%
1742
August1st to 15thNight
42145%36%7%7%12%43%
1800
16th to endNight
8%425%6%35%6%7%9%39%
1910
September1st to 15thNight
9%4245%35%5%6%7%43%
1866
16th to endNight
8%425%42345%6%52%
1903
October1st to 15thNight
10%413422325%57%
1815
16th to endNight
14%423212225%57%
2139
November1st to 15thNight
10%413323345%56%
2276
16th to endNight
14%6%2341434450%
2340
December1st to 15thNight
17%6%24423345%43%
2340
16th to endNight
23%5%25%423346%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
46%16%17%22%5%
1612
16th to endDay
42%15%23%21%5%
1911
February1st to 15thDay
44%26%24%17%4
1752
16th to endDay
45%26%16%24%4
1580
March1st to 15thDay
47%28%16%19%5%
1800
16th to endDay
42%211%23%18%1
2195
April1st to 15thDay
38%210%21%19%7%
2151
16th to endDay
37%38%24%22%3
2160
May1st to 15thDay
40%410%20%18%4
2301
16th to endDay
40%313%26%13%2
2435
June1st to 15thDay
40%6%15%21%15%1
2340
16th to endDay
33%6%13%25%16%4
2340
July1st to 15thDay
40%7%18%22%8%2
2201
16th to endDay
40%7%19%21%9%
2271
August1st to 15thDay
40%6%17%20%12%2
2148
16th to endDay
47%413%21%10%2
2292
September1st to 15thDay
43%412%20%13%5%
2081
16th to endDay
37%410%21%21%5%
1894
October1st to 15thDay
32%37%21%25%9%
1815
16th to endDay
31%1319%33%10%
1731
November1st to 15thDay
32%1420%29%9%
1582
16th to endDay
37%25%19%26%8%
1620
December1st to 15thDay
47%27%19%17%5%
1620
16th to endDay
53%17%20%14%3
1728
January1st to 15thNight
43%16%18%24%5%
2327
16th to endNight
44%25%19%20%7%
2310
February1st to 15thNight
40%16%22%21%7%
2112
16th to endNight
41%2421%24%5%
1893
March1st to 15thNight
42%28%20%19%7%
2160
16th to endNight
36%29%27%20%3
2037
April1st to 15thNight
34%210%25%19%8%
1797
16th to endNight
30%38%24%25%6%
1800
May1st to 15thNight
36%412%18%23%4
1648
16th to endNight
29%415%29%15%5%
1684
June1st to 15thNight
29%5%18%25%19%1
1620
16th to endNight
28%7%15%24%21%3
1620
July1st to 15thNight
35%7%20%22%9%4
1530
16th to endNight
34%6%21%23%13%
1631
August1st to 15thNight
28%7%20%24%15%3
1788
16th to endNight
38%6%17%21%12%3
1910
September1st to 15thNight
38%5%15%19%14%6%
1866
16th to endNight
31%39%23%23%8%
1903
October1st to 15thNight
30%26%21%25%13%
1815
16th to endNight
32%1313%34%14%
2139
November1st to 15thNight
29%25%19%28%15%
2276
16th to endNight
37%25%18%26%10%
2340
December1st to 15thNight
42%28%19%21%5%
2340
16th to endNight
48%27%19%16%5%
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
23%15%34%20%42
90
16th to endDay
29%20%39%7%3
96
February1st to 15thDay
28%20%36%13%1
90
16th to endDay
28%16%37%16%2
81
March1st to 15thDay
28%22%35%7%5%
90
16th to endDay
21%8%30%22%15%1
282
April1st to 15thDay
19%10%25%21%19%2
270
16th to endDay
14%7%24%26%25%2
270
May1st to 15thDay
16%425%25%17%10%
288
16th to endDay
13%319%26%19%17%
331
June1st to 15thDay
11%16%26%28%24%
315
16th to endDay
12%19%22%24%29%
315
July1st to 15thDay
7%7%25%30%27%
305
16th to endDay
10%1414%32%35%
326
August1st to 15thDay
12%16%23%30%25%
313
16th to endDay
16%327%33%18%
332
September1st to 15thDay
15%28%21%32%20%
315
16th to endDay
16%29%26%30%14%
283
October1st to 15thDay
13%317%33%25%6%
255
16th to endDay
18%418%34%18%6%
144
November1st to 15thDay
23%14%25%20%14%2
90
16th to endDay
15%16%34%17%13%2
90
December1st to 15thDay
26%18%32%16%41
90
16th to endDay
36%13%27%17%41
96
January1st to 15thNight
23%11%34%23%6%
720
16th to endNight
21%12%33%27%4
768
February1st to 15thNight
22%11%30%30%4
704
16th to endNight
22%12%31%30%3
631
March1st to 15thNight
21%11%30%29%6%
720
16th to endNight
16%10%27%28%15%
689
April1st to 15thNight
15%7%31%27%15%2
539
16th to endNight
13%5%25%34%18%1
540
May1st to 15thNight
11%322%31%27%3
540
16th to endNight
7%111%39%33%6%
563
June1st to 15thNight
6%8%30%41%12%
540
16th to endNight
48%23%46%15%
540
July1st to 15thNight
8%6%25%44%14%
510
16th to endNight
7%1420%46%19%
564
August1st to 15thNight
5%225%48%17%
539
16th to endNight
10%328%43%12%
573
September1st to 15thNight
12%19%25%39%11%
606
16th to endNight
9%111%35%36%5%
689
October1st to 15thNight
12%320%30%27%5%
660
16th to endNight
15%6%19%32%23%3
704
November1st to 15thNight
12%6%25%31%21%3
700
16th to endNight
18%9%27%28%15%
720
December1st to 15thNight
22%9%25%30%11%
720
16th to endNight
27%9%27%25%9%
768
Page generated at 2017-09-24 08:15:56. Version ac04

Copyright 2017 A. Danko


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