Carrollwood
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Carrollwood 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
62%
15933
21%
47169
17%
15892
66%
15892
30%
29556

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
47%
718
20%
2327
16%
716
54%
716
24%
1447
January16th to endNight
46%
768
23%
2391
18%
768
54%
768
27%
1488
February1st to 15thNight
47%
701
25%
2103
18%
698
55%
698
33%
1252
February16th to endNight
48%
631
24%
1866
14%
631
57%
631
33%
1126
March1st to 15thNight
50%
720
29%
1980
17%
720
60%
720
39%
1146
March16th to endNight
56%
768
27%
2112
21%
768
61%
768
39%
1235
April1st to 15thNight
61%
718
23%
1976
18%
718
64%
718
43%
1102
April16th to endNight
62%
696
27%
1863
19%
696
66%
696
40%
1093
May1st to 15thNight
76%
539
27%
1619
22%
539
79%
539
44%
867
May16th to endNight
76%
561
24%
1683
21%
561
77%
561
39%
982
June1st to 15thNight
71%
540
13%
1620
12%
540
72%
540
24%
1115
June16th to endNight
78%
540
9%
1620
9%
540
78%
540
25%
1127
July1st to 15thNight
76%
510
6%
1530
6%
510
76%
510
21%
1134
July16th to endNight
75%
564
7%
1595
7%
531
76%
531
21%
1152
August1st to 15thNight
79%
539
4%
1678
5%
536
79%
536
23%
1177
August16th to endNight
71%
687
9%
2024
10%
687
71%
687
20%
1454
September1st to 15thNight
66%
720
7%
1980
7%
720
66%
720
19%
1469
September16th to endNight
65%
717
15%
1980
15%
717
66%
717
23%
1395
October1st to 15thNight
69%
684
25%
1908
23%
684
72%
684
34%
1187
October16th to endNight
59%
704
28%
2112
25%
704
65%
704
34%
1240
November1st to 15thNight
62%
700
31%
2101
27%
700
69%
700
38%
1178
November16th to endNight
54%
720
29%
2265
24%
720
64%
720
35%
1292
December1st to 15thNight
52%
720
26%
2340
24%
720
59%
720
29%
1402
December16th to endNight
57%
768
24%
2496
23%
768
62%
768
28%
1496

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
8%5%25%6%46%6%6%9%38%
48010
Night
7%425%5%35%5%6%9%44%
47377
TransparencyDay
39%10%14%16%13%5%
47711
Night
34%8%16%19%15%5%
47180
SeeingDay
9%213%21%26%27%
5796
Night
8%217%33%28%9%
15941

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
11%5%34425%5%6%9%40%
1611
16th to endDay
11%4243245%5%6%47%
1830
February1st to 15thDay
13%424325%45%6%47%
1750
16th to endDay
7%5%2332345%8%52%
1604
March1st to 15thDay
5%32343445%8%53%
1980
16th to endDay
8%42443446%6%50%
2111
April1st to 15thDay
7%214445%47%9%47%
1972
16th to endDay
5%3245%3446%8%49%
2105
May1st to 15thDay
6%214325%5%5%8%54%
2331
16th to endDay
6%4247%47%5%6%10%39%
2431
June1st to 15thDay
11%5%36%7%47%7%7%11%26%
2340
16th to endDay
7%6%37%7%5%8%8%9%11%24%
2340
July1st to 15thDay
7%6%37%8%5%9%9%9%10%21%
2340
16th to endDay
7%6%39%9%5%10%8%8%10%21%
2465
August1st to 15thDay
7%5%38%8%6%9%9%9%10%20%
2267
16th to endDay
9%6%38%8%5%8%7%8%9%22%
2166
September1st to 15thDay
9%6%38%8%5%7%8%7%10%23%
1980
16th to endDay
9%7%39%7%5%5%7%8%9%24%
1980
October1st to 15thDay
6%5%36%6%46%6%6%8%39%
1850
16th to endDay
9%6%24434347%50%
1760
November1st to 15thDay
6%5%23425%5%48%51%
1757
16th to endDay
9%32443445%9%47%
1692
December1st to 15thDay
9%5%35%5%345%5%8%43%
1620
16th to endDay
6%5%24425%5%5%8%47%
1728
January1st to 15thNight
9%7%35%5%25%46%8%41%
2327
16th to endNight
12%5%34435%448%42%
2391
February1st to 15thNight
10%6%24413446%50%
2103
16th to endNight
7%6%35%5%2445%8%48%
1866
March1st to 15thNight
6%314425%46%7%53%
1980
16th to endNight
7%314324448%54%
2112
April1st to 15thNight
6%31432346%10%54%
1976
16th to endNight
7%22442445%6%55%
1863
May1st to 15thNight
43123245%5%10%57%
1619
16th to endNight
4314425%5%6%8%53%
1682
June1st to 15thNight
10%5%25%445%6%6%12%36%
1620
16th to endNight
6%325%6%46%6%9%12%35%
1620
July1st to 15thNight
5%5%15%6%48%6%10%14%31%
1620
16th to endNight
5%4247%48%8%10%12%31%
1703
August1st to 15thNight
44246%47%8%10%13%32%
1689
16th to endNight
8%425%5%37%6%9%12%32%
2024
September1st to 15thNight
7%5%27%7%5%7%7%8%12%28%
1980
16th to endNight
8%6%28%7%35%6%7%10%34%
1980
October1st to 15thNight
7%4244345%6%8%48%
1908
16th to endNight
9%5%26%323447%50%
2112
November1st to 15thNight
6%323434448%54%
2101
16th to endNight
7%4245%2446%8%48%
2265
December1st to 15thNight
9%5%25%434448%46%
2340
16th to endNight
7%4245%35%5%6%9%44%
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
37%6%11%20%18%5%
1612
16th to endDay
34%5%8%17%25%8%
1830
February1st to 15thDay
36%5%7%15%21%14%
1752
16th to endDay
30%5%13%15%22%11%
1604
March1st to 15thDay
27%6%11%24%21%8%
1980
16th to endDay
32%5%10%21%20%9%
2112
April1st to 15thDay
31%7%13%18%21%8%
1972
16th to endDay
31%5%11%20%23%6%
2105
May1st to 15thDay
27%7%13%23%20%8%
2331
16th to endDay
39%9%14%19%15%2
2435
June1st to 15thDay
48%11%17%16%4
2340
16th to endDay
49%15%19%12%3
2340
July1st to 15thDay
52%17%20%7%1
2201
16th to endDay
52%16%19%9%1
2310
August1st to 15thDay
51%17%23%7%
2254
16th to endDay
53%16%18%11%
2166
September1st to 15thDay
51%16%18%10%3
1980
16th to endDay
48%12%14%16%5%1
1980
October1st to 15thDay
40%9%9%15%15%9%
1850
16th to endDay
34%5%9%15%22%12%
1760
November1st to 15thDay
29%6%8%22%23%9%
1757
16th to endDay
32%6%9%18%19%12%
1692
December1st to 15thDay
37%6%11%20%17%5%
1620
16th to endDay
32%7%12%19%20%7%
1728
January1st to 15thNight
40%5%11%20%16%4
2327
16th to endNight
38%5%9%17%19%8%
2391
February1st to 15thNight
33%5%7%17%22%12%
2112
16th to endNight
33%5%13%16%21%8%
1866
March1st to 15thNight
28%5%11%27%19%7%
1980
16th to endNight
28%5%11%25%19%8%
2112
April1st to 15thNight
24%6%17%23%21%5%
1976
16th to endNight
28%5%12%23%23%6%
1863
May1st to 15thNight
22%7%14%29%19%7%
1620
16th to endNight
26%9%19%24%17%2
1684
June1st to 15thNight
40%11%20%20%7%
1620
16th to endNight
38%13%25%18%4
1620
July1st to 15thNight
38%19%29%9%2
1530
16th to endNight
39%17%29%12%1
1595
August1st to 15thNight
35%17%35%10%
1678
16th to endNight
40%16%26%14%1
2024
September1st to 15thNight
44%15%24%12%2
1980
16th to endNight
42%11%19%18%5%2
1980
October1st to 15thNight
32%8%12%18%19%8%
1908
16th to endNight
33%49%16%25%10%
2112
November1st to 15thNight
27%6%9%22%24%9%
2101
16th to endNight
31%5%11%21%17%12%
2265
December1st to 15thNight
36%5%11%25%16%5%
2340
16th to endNight
34%7%12%20%17%7%
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
15%7%31%24%18%2
90
16th to endDay
15%15%30%26%10%2
96
February1st to 15thDay
11%14%24%23%20%6%
90
16th to endDay
7%9%37%28%17%
105
March1st to 15thDay
7%5%32%34%17%2
270
16th to endDay
9%6%22%31%25%4
288
April1st to 15thDay
8%421%30%29%6%
270
16th to endDay
5%19%28%33%12%
270
May1st to 15thDay
7%213%27%27%21%
288
16th to endDay
7%7%17%34%32%
331
June1st to 15thDay
16%15%10%24%42%
315
16th to endDay
6%210%25%54%
315
July1st to 15thDay
5%1420%67%
305
16th to endDay
10%2310%19%53%
326
August1st to 15thDay
10%28%22%55%
313
16th to endDay
9%6%8%26%47%
332
September1st to 15thDay
13%6%13%28%38%
315
16th to endDay
12%215%36%31%
314
October1st to 15thDay
8%112%28%36%12%
278
16th to endDay
10%119%30%26%10%
272
November1st to 15thDay
7%114%36%29%10%
265
16th to endDay
7%125%37%22%5%
162
December1st to 15thDay
7%437%34%15%
90
16th to endDay
3220%44%26%3
96
January1st to 15thNight
11%6%25%38%16%1
720
16th to endNight
14%6%27%37%13%
768
February1st to 15thNight
12%6%28%37%14%
704
16th to endNight
9%430%41%13%
631
March1st to 15thNight
6%5%32%42%12%
720
16th to endNight
7%6%24%43%17%1
768
April1st to 15thNight
6%322%45%20%1
718
16th to endNight
8%320%43%23%
696
May1st to 15thNight
5%10%45%34%3
540
16th to endNight
5%8%38%38%8%
563
June1st to 15thNight
11%15%22%43%16%
540
16th to endNight
5%214%43%33%
540
July1st to 15thNight
7%17%44%39%
510
16th to endNight
6%28%40%41%
564
August1st to 15thNight
5%27%45%39%
539
16th to endNight
9%1414%41%28%
687
September1st to 15thNight
10%5%20%42%20%
720
16th to endNight
10%7%26%43%12%
717
October1st to 15thNight
9%12%40%32%4
684
16th to endNight
9%220%32%31%2
704
November1st to 15thNight
7%121%43%23%3
700
16th to endNight
8%326%42%18%1
720
December1st to 15thNight
9%425%38%20%
720
16th to endNight
8%422%40%21%1
768
Page generated at 2017-10-07 14:07:54. Version ac04

Copyright 2017 A. Danko


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