Murfreesboro
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Murfreesboro clear sky chart from 2005-11-05 to 2017-08-12.

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
46%
15143
22%
46258
16%
15100
53%
15100
27%
29160

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
24%
720
20%
2327
11%
716
35%
716
19%
1567
January16th to endNight
23%
768
20%
2392
9%
768
34%
768
18%
1655
February1st to 15thNight
22%
704
17%
2112
8%
701
31%
701
20%
1440
February16th to endNight
21%
631
20%
1893
9%
631
30%
631
20%
1294
March1st to 15thNight
26%
720
18%
2145
10%
720
33%
720
21%
1472
March16th to endNight
35%
720
20%
2064
13%
720
41%
720
24%
1374
April1st to 15thNight
39%
539
25%
1797
16%
539
52%
539
31%
1009
April16th to endNight
45%
540
24%
1764
16%
540
55%
540
30%
1033
May1st to 15thNight
46%
539
20%
1620
12%
539
53%
539
27%
1055
May16th to endNight
63%
561
18%
1683
14%
561
65%
561
30%
1042
June1st to 15thNight
69%
540
19%
1617
14%
540
72%
540
35%
961
June16th to endNight
76%
540
23%
1440
18%
540
77%
540
41%
856
July1st to 15thNight
70%
510
16%
1388
14%
510
70%
510
34%
871
July16th to endNight
77%
564
19%
1595
18%
531
78%
531
35%
948
August1st to 15thNight
77%
527
20%
1687
21%
524
78%
524
33%
987
August16th to endNight
73%
525
20%
1750
25%
525
73%
525
30%
1040
September1st to 15thNight
62%
566
21%
1721
19%
566
65%
566
28%
1109
September16th to endNight
62%
657
27%
1815
22%
657
65%
657
33%
1136
October1st to 15thNight
55%
660
34%
1815
26%
660
61%
660
37%
1084
October16th to endNight
48%
704
30%
2181
25%
704
56%
704
33%
1266
November1st to 15thNight
47%
700
29%
2276
25%
700
55%
700
33%
1267
November16th to endNight
37%
720
25%
2340
18%
720
48%
720
27%
1414
December1st to 15thNight
29%
720
19%
2340
12%
720
38%
720
20%
1563
December16th to endNight
27%
768
20%
2496
12%
768
37%
768
18%
1717

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%25%5%35%5%5%7%39%
47710
Night
13%6%25%42445%7%44%
46448
TransparencyDay
42%7%10%20%15%3
47403
Night
38%5%10%21%18%4
46259
SeeingDay
14%7%19%23%22%12%
5329
Night
15%8%24%28%19%3
15146

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
18%9%36%5%2433435%
1611
16th to endDay
19%7%35%42434439%
1830
February1st to 15thDay
17%10%37%6%2433435%
1750
16th to endDay
16%9%36%5%25%346%34%
1580
March1st to 15thDay
17%9%36%5%24435%36%
1815
16th to endDay
16%7%35%5%346%6%6%34%
2168
April1st to 15thDay
11%6%25%4235%6%7%44%
2151
16th to endDay
12%6%26%5%35%45%6%41%
2196
May1st to 15thDay
15%5%34434447%40%
2331
16th to endDay
10%6%35%6%45%5%5%7%39%
2431
June1st to 15thDay
6%425%5%45%6%7%9%41%
2340
16th to endDay
5%325%5%47%6%7%11%40%
2517
July1st to 15thDay
9%5%26%6%5%7%7%6%8%33%
2487
16th to endDay
7%426%7%48%6%7%10%33%
2465
August1st to 15thDay
5%5%15%7%47%7%8%9%37%
2173
16th to endDay
10%5%25%7%5%6%7%7%8%33%
2100
September1st to 15thDay
13%6%36%6%37%6%5%6%33%
1897
16th to endDay
10%5%25%5%34446%46%
1815
October1st to 15thDay
12%423423335%52%
1815
16th to endDay
15%413323345%52%
1688
November1st to 15thDay
13%5%22313346%53%
1582
16th to endDay
16%5%25%323445%48%
1620
December1st to 15thDay
19%8%46%5%23346%33%
1620
16th to endDay
19%9%25%5%23335%37%
1728
January1st to 15thNight
16%9%27%5%23435%39%
2327
16th to endNight
17%8%36%5%34445%36%
2392
February1st to 15thNight
18%8%35%423245%38%
2103
16th to endNight
17%8%245%3445%5%37%
1893
March1st to 15thNight
16%6%25%5%35%45%7%37%
2145
16th to endNight
14%8%25%424446%41%
2064
April1st to 15thNight
12%41342335%8%50%
1797
16th to endNight
11%424424446%48%
1764
May1st to 15thNight
12%6%25%5%34446%44%
1619
16th to endNight
6%4245%35%5%5%10%45%
1682
June1st to 15thNight
4315%5%4446%9%48%
1617
16th to endNight
2215%5%245%7%11%50%
1440
July1st to 15thNight
9%4235%25%5%6%11%42%
1470
16th to endNight
43245%36%6%7%13%43%
1703
August1st to 15thNight
5%314435%5%7%11%46%
1698
16th to endNight
7%425%4345%7%10%43%
1750
September1st to 15thNight
10%6%26%5%25%5%47%42%
1721
16th to endNight
10%425%5%33448%48%
1815
October1st to 15thNight
12%313422337%53%
1815
16th to endNight
15%5%23312335%52%
2181
November1st to 15thNight
12%424413336%53%
2276
16th to endNight
16%5%23323336%48%
2340
December1st to 15thNight
18%7%35%5%2345%5%37%
2340
16th to endNight
20%8%45%5%23335%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
51%5%6%18%16%1
1612
16th to endDay
48%49%22%13%2
1830
February1st to 15thDay
52%47%19%13%2
1752
16th to endDay
50%49%19%12%2
1580
March1st to 15thDay
50%5%8%16%14%4
1815
16th to endDay
47%7%11%19%12%
2169
April1st to 15thDay
37%7%9%22%19%4
2151
16th to endDay
41%6%8%22%17%3
2196
May1st to 15thDay
43%7%10%21%14%2
2331
16th to endDay
42%8%13%21%11%2
2435
June1st to 15thDay
36%10%14%22%15%1
2340
16th to endDay
34%10%13%19%17%4
2517
July1st to 15thDay
43%10%16%14%10%3
2340
16th to endDay
40%11%17%19%9%1
2310
August1st to 15thDay
37%11%16%18%14%2
2160
16th to endDay
44%9%12%18%12%2
2100
September1st to 15thDay
46%9%10%16%12%4
1897
16th to endDay
37%6%10%18%23%3
1815
October1st to 15thDay
34%5%7%20%26%5%
1815
16th to endDay
34%47%20%27%6%
1688
November1st to 15thDay
33%46%21%26%7%
1582
16th to endDay
38%45%26%20%4
1620
December1st to 15thDay
51%46%20%12%3
1620
16th to endDay
49%5%11%18%13%1
1728
January1st to 15thNight
47%48%19%16%3
2327
16th to endNight
49%5%8%19%14%3
2392
February1st to 15thNight
48%311%20%14%2
2112
16th to endNight
48%49%20%15%2
1893
March1st to 15thNight
46%6%9%17%15%5%
2145
16th to endNight
43%5%11%25%13%1
2064
April1st to 15thNight
32%412%23%21%4
1797
16th to endNight
34%5%9%24%21%3
1764
May1st to 15thNight
40%6%10%23%17%1
1620
16th to endNight
33%9%16%22%14%3
1684
June1st to 15thNight
31%6%13%30%15%1
1617
16th to endNight
24%9%16%27%15%5%
1440
July1st to 15thNight
32%8%19%21%14%3
1388
16th to endNight
28%9%19%25%14%2
1595
August1st to 15thNight
27%10%16%25%17%2
1687
16th to endNight
33%7%15%23%16%3
1750
September1st to 15thNight
38%7%13%18%17%4
1721
16th to endNight
35%5%6%20%25%6%
1815
October1st to 15thNight
30%5%7%19%27%8%
1815
16th to endNight
35%25%20%27%8%
2181
November1st to 15thNight
33%26%19%26%10%
2276
16th to endNight
38%47%21%22%4
2340
December1st to 15thNight
47%5%8%19%15%3
2340
16th to endNight
50%48%18%15%1
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
24%24%30%12%8%
90
16th to endDay
25%21%40%8%4
96
February1st to 15thDay
23%30%36%7%2
90
16th to endDay
28%22%29%17%2
81
March1st to 15thDay
22%26%36%9%3
105
16th to endDay
17%11%32%23%14%
288
April1st to 15thDay
12%14%29%27%13%2
270
16th to endDay
17%8%26%24%17%5%
270
May1st to 15thDay
18%10%25%22%13%8%
288
16th to endDay
16%5%19%26%17%14%
331
June1st to 15thDay
7%217%16%31%24%
315
16th to endDay
5%315%31%26%17%
492
July1st to 15thDay
10%113%31%26%15%
444
16th to endDay
6%8%17%30%34%
326
August1st to 15thDay
10%18%21%37%21%
297
16th to endDay
15%5%20%38%19%
268
September1st to 15thDay
12%29%19%32%22%
255
16th to endDay
16%311%27%33%7%
254
October1st to 15thDay
14%224%23%27%6%
255
16th to endDay
19%5%19%31%19%4
148
November1st to 15thDay
14%12%20%37%14%1
90
16th to endDay
18%18%35%14%11%1
90
December1st to 15thDay
24%17%32%17%6%1
90
16th to endDay
20%22%37%16%2
96
January1st to 15thNight
22%19%29%23%4
720
16th to endNight
22%15%36%23%2
768
February1st to 15thNight
23%13%36%22%3
704
16th to endNight
23%16%35%21%2
631
March1st to 15thNight
20%14%35%24%4
720
16th to endNight
18%12%28%26%12%1
720
April1st to 15thNight
14%10%34%28%11%1
539
16th to endNight
14%7%30%35%11%1
540
May1st to 15thNight
13%5%28%30%20%1
540
16th to endNight
8%118%38%26%6%
563
June1st to 15thNight
5%16%35%34%7%
540
16th to endNight
311%34%41%8%
540
July1st to 15thNight
10%19%34%38%6%
510
16th to endNight
48%26%45%14%
564
August1st to 15thNight
7%6%29%47%9%
527
16th to endNight
8%6%34%40%8%
525
September1st to 15thNight
12%212%27%38%6%
566
16th to endNight
12%215%29%37%2
657
October1st to 15thNight
13%5%18%29%27%5%
660
16th to endNight
18%6%23%31%18%2
704
November1st to 15thNight
14%8%25%28%19%3
700
16th to endNight
18%13%27%27%12%
720
December1st to 15thNight
24%11%30%24%8%
720
16th to endNight
26%14%28%25%4
768
Page generated at 2017-08-13 13:16:43. Version ac04

Copyright 2017 A. Danko


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