Collierville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Collierville clear sky chart from 2005-11-06 to 2024-01-17.

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
47%
24049
16%
74564
11%
23993
52%
23993
16%
54737

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 10thNight
25%
950
14%
2591
5%
946
32%
946
13%
2031
January11th to 20thNight
24%
935
14%
2431
4%
935
31%
935
12%
1965
January21st to endNight
25%
990
16%
2574
5%
990
32%
990
14%
2038
February1st to 10thNight
24%
741
13%
2181
5%
741
30%
741
13%
1698
February11th to 20thNight
23%
703
13%
2099
6%
700
28%
700
12%
1624
February21st to endNight
23%
592
15%
1776
5%
592
31%
592
11%
1398
March1st to 10thNight
31%
720
15%
2160
8%
720
37%
720
15%
1585
March11th to 20thNight
30%
563
13%
2003
7%
563
36%
563
10%
1551
March21st to endNight
35%
594
13%
2034
7%
594
41%
594
11%
1560
April1st to 10thNight
37%
540
16%
1800
11%
540
45%
540
15%
1298
April11th to 20thNight
39%
533
21%
1775
15%
533
51%
533
18%
1215
April21st to endNight
41%
540
17%
1800
12%
540
51%
540
15%
1309
May1st to 10thNight
47%
540
11%
1800
10%
540
51%
540
14%
1353
May11th to 20thNight
53%
531
15%
1624
12%
531
57%
531
15%
1219
May21st to endNight
64%
583
16%
1652
15%
582
66%
582
20%
1204
June1st to 10thNight
65%
540
16%
1440
12%
540
68%
540
20%
1080
June11th to 20thNight
79%
540
22%
1440
18%
540
80%
540
27%
995
June21st to endNight
77%
540
20%
1440
16%
540
79%
540
26%
998
July1st to 10thNight
74%
525
16%
1400
14%
525
75%
525
20%
1049
July11th to 20thNight
76%
522
14%
1464
12%
522
78%
522
19%
1067
July21st to endNight
79%
591
15%
1681
17%
558
80%
558
20%
1211
August1st to 10thNight
83%
537
16%
1778
18%
534
85%
534
22%
1184
August11th to 20thNight
76%
534
18%
1776
21%
534
77%
534
18%
1250
August21st to endNight
74%
594
15%
1980
17%
594
76%
594
17%
1408
September1st to 10thNight
74%
540
16%
1800
18%
540
75%
540
15%
1319
September11th to 20thNight
67%
589
18%
1849
16%
589
69%
589
16%
1364
September21st to endNight
64%
720
19%
1980
14%
720
67%
720
21%
1424
October1st to 10thNight
64%
720
22%
2061
18%
720
66%
720
24%
1391
October11th to 20thNight
52%
720
21%
2160
14%
720
59%
720
19%
1529
October21st to endNight
44%
792
18%
2376
13%
792
50%
792
16%
1756
November1st to 10thNight
51%
740
21%
2374
18%
740
58%
740
20%
1620
November11th to 20thNight
40%
760
19%
2470
12%
760
49%
760
15%
1790
November21st to endNight
38%
760
15%
2470
11%
760
44%
760
13%
1857
December1st to 10thNight
32%
760
16%
2470
9%
760
41%
760
12%
1874
December11th to 20thNight
32%
932
17%
3116
7%
932
39%
932
12%
2282
December21st to endNight
26%
1038
8%
4739
5%
1026
33%
1026
8%
3241

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
12%6%35%5%35%5%5%7%44%
74781
Night
12%6%2443445%7%48%
75053
TransparencyDay
25%38%7%14%13%3
74496
Night
23%37%7%14%14%4
74859
SeeingDay
14%8%21%25%21%10%
14164
Night
15%8%25%31%19%3
24059

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 10thDay
18%10%35%5%23335%44%
1569
11th to 20thDay
20%8%36%5%34345%38%
1674
21st to endDay
15%7%35%5%33336%48%
1782
February1st to 10thDay
20%9%47%423335%39%
1777
11th to 20thDay
20%8%45%43445%5%38%
1748
21st to endDay
23%9%46%423445%36%
1480
March1st to 10thDay
16%7%37%5%34446%41%
1800
11th to 20thDay
19%9%48%5%34445%35%
1970
21st to endDay
17%7%37%6%45%45%7%37%
2321
April1st to 10thDay
12%6%25%5%35%5%5%6%46%
2160
11th to 20thDay
17%6%25%42445%6%45%
2134
21st to endDay
14%5%26%6%445%6%7%42%
2160
May1st to 10thDay
15%5%25%5%25%5%5%6%43%
2160
11th to 20thDay
12%5%25%5%345%6%9%43%
2265
21st to endDay
8%5%36%6%46%6%8%9%39%
2619
June1st to 10thDay
8%426%6%46%6%6%10%42%
2520
11th to 20thDay
4425%5%46%6%7%10%49%
2520
21st to endDay
44245%46%6%7%11%47%
2520
July1st to 10thDay
7%436%7%47%7%8%10%36%
2520
11th to 20thDay
7%325%6%46%6%8%12%40%
2444
21st to endDay
7%425%7%5%7%7%7%10%41%
2537
August1st to 10thDay
6%435%6%46%6%9%11%40%
2148
11th to 20thDay
9%5%26%5%36%6%8%9%42%
2125
21st to endDay
9%5%25%6%46%6%7%10%41%
2376
September1st to 10thDay
9%5%25%5%45%6%6%9%44%
2160
11th to 20thDay
11%5%25%5%25%5%5%8%46%
2093
21st to endDay
9%5%25%423437%55%
1980
October1st to 10thDay
7%4244245%5%6%57%
1894
11th to 20thDay
12%5%144235%5%5%55%
1800
21st to endDay
19%6%2342344451%
1980
November1st to 10thDay
12%5%13322345%60%
1702
11th to 20thDay
14%5%34423446%52%
1710
21st to endDay
20%7%344235%46%44%
1710
December1st to 10thDay
21%7%36%5%34445%38%
1710
11th to 20thDay
14%8%36%5%3444444%
1930
21st to endDay
14%11%37%5%445%5%6%36%
2783
January1st to 10thNight
19%7%35%423245%46%
2591
11th to 20thNight
18%11%36%424346%38%
2431
21st to endNight
17%7%35%423336%47%
2574
February1st to 10thNight
20%8%46%5%23345%41%
2181
11th to 20thNight
19%8%46%5%33325%43%
2098
21st to endNight
21%7%36%5%24336%39%
1776
March1st to 10thNight
16%6%34434446%46%
2160
11th to 20thNight
19%7%36%5%34346%40%
2003
21st to endNight
15%6%25%6%25%46%7%41%
2034
April1st to 10thNight
11%6%245%3345%8%48%
1800
11th to 20thNight
14%5%2432345%7%50%
1775
21st to endNight
11%5%245%3445%7%50%
1800
May1st to 10thNight
13%5%3442345%7%50%
1800
11th to 20thNight
11%6%25%4445%6%7%48%
1624
21st to endNight
6%5%246%36%7%8%12%42%
1651
June1st to 10thNight
7%426%5%35%5%6%10%47%
1440
11th to 20thNight
221432446%10%61%
1440
21st to endNight
32134346%6%13%56%
1440
July1st to 10thNight
3335%6%45%5%8%10%48%
1440
11th to 20thNight
7%3243236%6%12%51%
1512
21st to endNight
5%313435%6%7%11%53%
1780
August1st to 10thNight
33134346%8%11%54%
1790
11th to 20thNight
6%325%425%6%7%10%48%
1776
21st to endNight
6%5%245%345%7%10%50%
1980
September1st to 10thNight
7%425%435%5%5%7%54%
1800
11th to 20thNight
9%5%2443445%8%52%
1849
21st to endNight
9%424423346%58%
1980
October1st to 10thNight
8%313423348%61%
2061
11th to 20thNight
12%5%14322346%57%
2160
21st to endNight
18%6%3432334452%
2376
November1st to 10thNight
10%423423346%58%
2374
11th to 20thNight
11%42443445%6%54%
2470
21st to endNight
15%5%25%424446%50%
2470
December1st to 10thNight
17%9%25%423445%44%
2470
11th to 20thNight
16%7%35%5%23446%47%
3263
21st to endNight
15%8%35%6%35%5%5%6%36%
4884

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 10thDay
27%39%6%14%11%2
1570
11th to 20thDay
29%40%5%13%11%1
1674
21st to endDay
29%37%6%13%15%1
1782
February1st to 10thDay
32%37%413%13%2
1777
11th to 20thDay
31%37%410%13%4
1758
21st to endDay
35%36%6%9%11%3
1480
March1st to 10thDay
28%37%6%11%14%5%
1800
11th to 20thDay
36%38%6%10%10%2
1970
21st to endDay
33%37%6%15%9%1
2321
April1st to 10thDay
26%38%5%16%13%3
2160
11th to 20thDay
24%36%6%14%17%4
2134
21st to endDay
27%38%6%15%13%1
2160
May1st to 10thDay
32%38%8%11%10%2
2160
11th to 20thDay
24%40%10%13%11%1
2269
21st to endDay
23%41%11%18%7%1
2619
June1st to 10thDay
22%40%8%17%12%1
2520
11th to 20thDay
17%38%8%20%13%3
2520
21st to endDay
17%39%9%16%15%4
2520
July1st to 10thDay
25%41%10%12%10%3
2451
11th to 20thDay
24%42%13%10%7%4
2369
21st to endDay
24%42%11%17%6%
2396
August1st to 10thDay
22%40%11%18%8%1
2136
11th to 20thDay
21%39%9%17%10%2
2125
21st to endDay
22%39%7%18%11%3
2376
September1st to 10thDay
25%40%7%12%11%4
2160
11th to 20thDay
27%37%6%10%15%4
2093
21st to endDay
17%36%6%13%20%7%
1980
October1st to 10thDay
17%37%5%15%19%7%
1894
11th to 20thDay
21%37%5%14%19%6%
1800
21st to endDay
24%38%313%18%4
1980
November1st to 10thDay
13%40%5%17%19%5%
1702
11th to 20thDay
21%39%6%12%16%5%
1710
21st to endDay
25%39%5%11%15%5%
1710
December1st to 10thDay
29%40%5%11%12%3
1710
11th to 20thDay
29%33%6%13%18%2
1927
21st to endDay
34%28%8%18%10%2
2783
January1st to 10thNight
27%40%5%13%13%2
2591
11th to 20thNight
29%40%5%13%11%2
2431
21st to endNight
30%37%412%15%2
2574
February1st to 10thNight
31%35%7%12%13%2
2181
11th to 20thNight
30%36%413%12%5%
2099
21st to endNight
31%36%5%10%13%4
1776
March1st to 10thNight
24%36%6%13%14%7%
2160
11th to 20thNight
31%37%7%11%10%3
2003
21st to endNight
30%37%7%14%10%2
2034
April1st to 10thNight
22%38%7%15%13%5%
1800
11th to 20thNight
19%36%6%14%19%6%
1775
21st to endNight
24%37%6%18%13%1
1800
May1st to 10thNight
25%38%9%13%10%4
1800
11th to 20thNight
23%40%9%14%13%2
1625
21st to endNight
18%40%10%20%11%1
1652
June1st to 10thNight
19%40%9%16%14%1
1440
11th to 20thNight
12%38%9%20%17%4
1440
21st to endNight
12%38%11%16%18%4
1440
July1st to 10thNight
18%42%10%17%10%3
1400
11th to 20thNight
18%41%13%14%10%4
1464
21st to endNight
16%42%13%20%9%
1681
August1st to 10thNight
12%39%13%23%12%1
1778
11th to 20thNight
18%39%10%18%12%3
1776
21st to endNight
19%39%10%15%12%5%
1980
September1st to 10thNight
23%39%7%9%16%6%
1800
11th to 20thNight
23%38%7%10%18%4
1849
21st to endNight
20%37%5%14%18%7%
1980
October1st to 10thNight
15%36%5%16%18%10%
2061
11th to 20thNight
20%36%6%11%19%8%
2160
21st to endNight
24%37%412%17%5%
2376
November1st to 10thNight
14%40%416%19%7%
2374
11th to 20thNight
20%41%6%12%15%7%
2470
21st to endNight
24%40%412%15%5%
2470
December1st to 10thNight
26%39%5%14%13%3
2470
11th to 20thNight
27%33%5%15%17%3
3265
21st to endNight
32%28%10%15%12%3
4884

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 10thDay
25%17%35%14%7%1
270
11th to 20thDay
27%17%36%15%41
258
21st to endDay
19%23%39%17%3
264
February1st to 10thDay
25%17%38%13%5%1
240
11th to 20thDay
35%18%33%11%3
240
21st to endDay
39%18%29%9%5%
198
March1st to 10thDay
21%18%35%19%42
240
11th to 20thDay
23%22%33%22%1
240
21st to endDay
20%18%32%21%7%1
407
April1st to 10thDay
15%17%32%25%9%1
420
11th to 20thDay
19%14%32%23%9%3
412
21st to endDay
19%12%30%23%13%3
420
May1st to 10thDay
19%10%26%28%14%3
423
11th to 20thDay
15%5%23%24%23%10%
447
21st to endDay
10%420%29%24%13%
573
June1st to 10thDay
10%415%26%27%18%
630
11th to 20thDay
4215%34%31%14%
630
21st to endDay
5%217%30%32%14%
630
July1st to 10thDay
7%110%27%34%22%
621
11th to 20thDay
7%29%23%37%21%
618
21st to endDay
6%19%27%36%20%
675
August1st to 10thDay
7%38%28%34%20%
446
11th to 20thDay
13%17%31%35%14%
439
21st to endDay
13%15%21%35%25%
495
September1st to 10thDay
10%19%27%37%17%
450
11th to 20thDay
10%213%21%36%19%
450
21st to endDay
13%314%33%22%14%
450
October1st to 10thDay
9%419%30%31%7%
364
11th to 20thDay
10%9%35%29%12%4
270
21st to endDay
25%10%27%27%8%2
297
November1st to 10thDay
18%9%21%36%12%4
270
11th to 20thDay
9%15%36%28%10%1
270
21st to endDay
24%12%29%18%13%3
270
December1st to 10thDay
24%18%30%19%7%2
270
11th to 20thDay
22%17%32%19%9%1
270
21st to endDay
24%19%36%16%5%1
297
January1st to 10thNight
24%13%34%24%5%
950
11th to 20thNight
25%16%32%24%4
935
21st to endNight
20%12%39%26%2
990
February1st to 10thNight
23%13%36%24%4
741
11th to 20thNight
24%17%33%23%2
703
21st to endNight
25%16%33%23%3
592
March1st to 10thNight
20%13%31%30%5%
720
11th to 20thNight
24%10%34%28%41
563
21st to endNight
18%11%32%27%12%
594
April1st to 10thNight
15%10%36%30%9%1
540
11th to 20thNight
17%8%31%31%12%1
533
21st to endNight
14%9%32%33%11%1
540
May1st to 10thNight
14%8%26%36%13%2
540
11th to 20thNight
12%5%23%37%19%4
531
21st to endNight
8%215%41%28%6%
584
June1st to 10thNight
9%114%37%32%7%
540
11th to 20thNight
2112%36%46%3
540
21st to endNight
4112%39%37%6%
540
July1st to 10thNight
2110%31%45%11%
525
11th to 20thNight
6%28%28%42%14%
522
21st to endNight
5%18%30%45%12%
591
August1st to 10thNight
5%432%49%9%
537
11th to 20thNight
7%16%36%42%7%
534
21st to endNight
7%110%26%47%9%
594
September1st to 10thNight
8%27%36%41%6%
540
11th to 20thNight
11%312%30%37%8%
589
21st to endNight
10%415%36%31%5%
720
October1st to 10thNight
9%319%35%30%4
720
11th to 20thNight
14%5%25%37%17%2
720
21st to endNight
21%6%24%31%17%2
792
November1st to 10thNight
12%6%25%37%18%2
740
11th to 20thNight
12%9%35%33%11%1
760
21st to endNight
18%9%32%30%11%1
760
December1st to 10thNight
23%11%31%29%6%
760
11th to 20thNight
22%10%31%30%7%
934
21st to endNight
25%13%31%27%4
1045
Page generated at 2024-01-14 08:55:04. Version ac07

Copyright 2024 Attilla Danko


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