Sarasota
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sarasota clear sky chart from 2005-11-05 to 2018-01-12.

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
65%
16354
20%
48394
18%
16315
68%
16315
31%
30200

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
53%
762
18%
2472
15%
761
59%
761
25%
1560
January16th to endNight
52%
768
24%
2373
21%
768
58%
768
30%
1440
February1st to 15thNight
50%
701
25%
2104
19%
699
57%
699
33%
1262
February16th to endNight
58%
631
24%
1860
17%
631
65%
631
36%
1089
March1st to 15thNight
58%
720
30%
1980
19%
720
66%
720
44%
1093
March16th to endNight
63%
768
27%
2112
21%
768
67%
768
41%
1201
April1st to 15thNight
67%
718
22%
1976
18%
718
70%
718
44%
1101
April16th to endNight
65%
719
27%
1897
19%
719
69%
719
42%
1120
May1st to 15thNight
79%
539
29%
1619
26%
539
81%
539
45%
857
May16th to endNight
78%
561
24%
1683
21%
561
79%
561
37%
999
June1st to 15thNight
72%
540
11%
1620
10%
540
72%
540
25%
1110
June16th to endNight
80%
540
9%
1620
8%
540
81%
540
25%
1105
July1st to 15thNight
76%
510
6%
1530
6%
510
76%
510
20%
1130
July16th to endNight
77%
564
8%
1595
9%
531
78%
531
22%
1127
August1st to 15thNight
80%
539
4%
1703
5%
536
80%
536
23%
1171
August16th to endNight
67%
697
8%
2034
8%
697
67%
697
19%
1505
September1st to 15thNight
68%
720
7%
1980
8%
720
68%
720
18%
1474
September16th to endNight
64%
717
12%
1980
12%
717
64%
717
20%
1455
October1st to 15thNight
72%
720
24%
2004
24%
720
73%
720
34%
1247
October16th to endNight
59%
768
26%
2304
24%
768
64%
768
32%
1402
November1st to 15thNight
65%
760
29%
2281
26%
760
71%
760
38%
1285
November16th to endNight
58%
780
29%
2428
25%
780
65%
780
35%
1406
December1st to 15thNight
59%
780
24%
2535
23%
780
63%
780
29%
1506
December16th to endNight
62%
832
25%
2704
26%
832
65%
832
32%
1555

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
7%425%5%46%6%7%9%39%
48926
Night
6%425%5%35%5%6%10%44%
48601
TransparencyDay
37%10%16%17%13%4
48627
Night
33%9%16%20%14%5%
48404
SeeingDay
9%212%22%28%25%
6169
Night
8%214%32%30%11%
16363

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
10%6%26%426%5%7%10%38%
1710
16th to endDay
10%425%425%46%8%46%
1849
February1st to 15thDay
10%5%3432446%6%48%
1750
16th to endDay
7%32442345%8%54%
1613
March1st to 15thDay
421332446%8%57%
1980
16th to endDay
7%42342345%8%52%
2111
April1st to 15thDay
5%3245%345%7%10%48%
1972
16th to endDay
6%214335%5%6%8%52%
2070
May1st to 15thDay
421331347%9%56%
2331
16th to endDay
6%325%5%37%6%6%8%41%
2431
June1st to 15thDay
10%6%36%7%47%7%8%11%26%
2340
16th to endDay
7%5%26%7%48%9%10%11%24%
2340
July1st to 15thDay
8%5%37%8%6%9%8%10%11%21%
2340
16th to endDay
6%5%27%8%6%9%10%9%12%20%
2465
August1st to 15thDay
5%5%26%7%6%9%10%10%12%21%
2241
16th to endDay
10%426%9%5%9%9%10%10%21%
2154
September1st to 15thDay
9%5%27%7%6%9%8%9%9%23%
1980
16th to endDay
8%6%36%8%5%6%8%8%12%24%
1980
October1st to 15thDay
6%416%7%5%6%6%7%8%39%
1956
16th to endDay
8%6%25%43445%8%47%
1920
November1st to 15thDay
4324435%46%8%51%
1907
16th to endDay
7%424435%45%7%49%
1859
December1st to 15thDay
7%435%5%36%5%6%9%43%
1755
16th to endDay
5%425%5%3445%10%47%
1872
January1st to 15thNight
8%6%36%445%5%6%10%38%
2472
16th to endNight
10%5%24425%5%6%8%42%
2373
February1st to 15thNight
11%425%424345%49%
2103
16th to endNight
5%5%23425%6%6%9%48%
1860
March1st to 15thNight
42134245%6%9%55%
1980
16th to endNight
5%32442445%8%54%
2112
April1st to 15thNight
421342447%9%55%
1976
16th to endNight
5%3144345%6%9%52%
1897
May1st to 15thNight
222233435%8%59%
1619
16th to endNight
5%324435%5%5%9%50%
1682
June1st to 15thNight
9%5%25%5%47%5%6%10%35%
1620
16th to endNight
5%4245%35%7%11%13%35%
1620
July1st to 15thNight
6%5%25%5%47%6%10%12%32%
1620
16th to endNight
4325%6%48%9%10%14%30%
1703
August1st to 15thNight
4425%6%36%6%9%16%33%
1714
16th to endNight
9%436%7%46%7%8%12%29%
2034
September1st to 15thNight
6%5%26%8%48%7%9%11%27%
1980
16th to endNight
9%6%28%6%46%6%8%11%28%
1980
October1st to 15thNight
5%315%5%36%5%6%9%46%
2004
16th to endNight
9%5%245%2345%8%46%
2304
November1st to 15thNight
43245%35%45%7%53%
2281
16th to endNight
7%4245%3445%9%49%
2428
December1st to 15thNight
8%425%5%35%5%6%8%44%
2535
16th to endNight
6%4245%345%5%9%47%
2704

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%7%11%23%15%4
1711
16th to endDay
34%6%9%21%21%7%
1849
February1st to 15thDay
35%5%8%18%19%12%
1752
16th to endDay
29%5%13%18%22%9%
1613
March1st to 15thDay
23%5%14%26%22%7%
1980
16th to endDay
28%5%13%23%21%7%
2112
April1st to 15thDay
28%8%17%20%20%5%
1972
16th to endDay
27%7%15%19%25%4
2070
May1st to 15thDay
22%7%16%26%20%6%
2331
16th to endDay
35%10%15%22%13%1
2435
June1st to 15thDay
47%11%21%16%3
2340
16th to endDay
45%17%23%12%2
2340
July1st to 15thDay
51%19%20%5%2
2201
16th to endDay
47%17%22%10%
2310
August1st to 15thDay
45%20%27%7%
2228
16th to endDay
50%19%20%9%
2154
September1st to 15thDay
49%16%22%9%1
1980
16th to endDay
46%15%17%13%41
1980
October1st to 15thDay
38%9%11%17%16%7%
1956
16th to endDay
35%5%9%17%19%11%
1920
November1st to 15thDay
29%5%10%23%23%7%
1907
16th to endDay
32%6%11%19%18%11%
1859
December1st to 15thDay
37%6%13%21%16%5%
1755
16th to endDay
32%6%13%23%18%5%
1872
January1st to 15thNight
40%5%12%23%13%3
2472
16th to endNight
36%5%10%20%19%6%
2373
February1st to 15thNight
35%37%18%21%12%
2112
16th to endNight
29%6%13%20%21%7%
1860
March1st to 15thNight
24%5%13%29%20%6%
1980
16th to endNight
27%5%13%24%22%7%
2112
April1st to 15thNight
23%7%18%25%19%5%
1976
16th to endNight
27%6%13%23%25%4
1897
May1st to 15thNight
21%7%12%31%20%6%
1620
16th to endNight
28%9%17%27%17%1
1684
June1st to 15thNight
41%9%23%19%5%
1620
16th to endNight
32%18%27%16%5%
1620
July1st to 15thNight
39%18%30%8%1
1530
16th to endNight
35%18%30%14%
1595
August1st to 15thNight
33%18%36%10%
1703
16th to endNight
42%16%26%12%1
2034
September1st to 15thNight
43%16%23%13%2
1980
16th to endNight
44%13%20%15%41
1980
October1st to 15thNight
31%9%15%18%19%6%
2004
16th to endNight
34%6%10%15%22%10%
2304
November1st to 15thNight
29%5%9%24%22%9%
2281
16th to endNight
31%6%11%21%18%11%
2428
December1st to 15thNight
35%6%12%24%16%4
2535
16th to endNight
31%6%13%24%17%5%
2704

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
19%8%27%27%13%2
123
16th to endDay
9%14%35%27%11%2
96
February1st to 15thDay
12%8%28%28%16%4
90
16th to endDay
9%133%35%18%
114
March1st to 15thDay
5%228%38%22%2
270
16th to endDay
10%321%34%25%4
288
April1st to 15thDay
5%122%35%28%5%
270
16th to endDay
7%11%36%36%7%
270
May1st to 15thDay
6%111%28%34%16%
288
16th to endDay
6%7%18%35%31%
331
June1st to 15thDay
17%16%13%26%34%
315
16th to endDay
6%39%27%52%
315
July1st to 15thDay
5%1424%63%
305
16th to endDay
11%211%21%52%
326
August1st to 15thDay
8%26%26%54%
313
16th to endDay
10%37%27%49%
332
September1st to 15thDay
13%1311%27%42%
315
16th to endDay
7%1315%40%32%
314
October1st to 15thDay
7%19%30%36%14%
315
16th to endDay
13%316%31%25%9%
336
November1st to 15thDay
5%112%33%37%8%
325
16th to endDay
8%120%36%27%5%
239
December1st to 15thDay
5%335%34%16%3
135
16th to endDay
4211%35%37%8%
144
January1st to 15thNight
12%421%38%21%1
765
16th to endNight
11%5%23%42%16%
768
February1st to 15thNight
12%424%40%16%
704
16th to endNight
8%324%43%19%
631
March1st to 15thNight
5%228%43%18%1
720
16th to endNight
6%221%46%21%2
768
April1st to 15thNight
5%218%47%24%1
718
16th to endNight
7%219%43%26%1
719
May1st to 15thNight
48%43%38%3
540
16th to endNight
6%5%33%43%9%
563
June1st to 15thNight
10%218%50%18%
540
16th to endNight
5%1110%45%36%
540
July1st to 15thNight
7%2441%43%
510
16th to endNight
417%39%46%
564
August1st to 15thNight
5%8%38%46%
539
16th to endNight
12%310%38%34%
697
September1st to 15thNight
8%1415%43%25%
720
16th to endNight
11%5%21%44%16%
717
October1st to 15thNight
7%9%38%37%6%
720
16th to endNight
11%118%34%30%4
768
November1st to 15thNight
5%119%44%25%2
760
16th to endNight
7%322%42%22%2
780
December1st to 15thNight
9%319%39%26%1
780
16th to endNight
6%219%40%28%2
832
Page generated at 2018-01-12 22:01:33. Version ac04

Copyright 2018 A. Danko


Sarasota Clear Sky Chart |Charts Home