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Tampa
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Tampa clear sky chart from 2005-11-05 to 2019-05-11.

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
59%
18134
22%
53656
17%
18094
65%
18094
31%
33072

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
49%
838
24%
2717
18%
836
58%
836
27%
1641
January16th to endNight
43%
896
25%
2791
19%
896
52%
896
28%
1714
February1st to 15thNight
48%
821
25%
2464
18%
819
56%
819
33%
1473
February16th to endNight
50%
735
25%
2169
16%
735
59%
735
35%
1257
March1st to 15thNight
49%
840
30%
2310
17%
840
60%
840
41%
1299
March16th to endNight
54%
896
28%
2464
20%
896
61%
896
41%
1409
April1st to 15thNight
55%
838
24%
2306
17%
838
60%
838
42%
1283
April16th to endNight
55%
817
27%
2159
18%
817
61%
817
43%
1237
May1st to 15thNight
74%
616
28%
1851
22%
616
77%
616
44%
994
May16th to endNight
71%
609
22%
1827
18%
609
74%
609
36%
1107
June1st to 15thNight
70%
585
13%
1755
12%
585
70%
585
26%
1183
June16th to endNight
76%
585
8%
1755
7%
585
76%
585
25%
1216
July1st to 15thNight
76%
555
5%
1665
5%
555
76%
555
22%
1214
July16th to endNight
73%
612
6%
1739
6%
579
74%
579
21%
1254
August1st to 15thNight
76%
575
6%
1784
6%
572
76%
572
26%
1223
August16th to endNight
68%
751
9%
2200
10%
751
68%
751
21%
1584
September1st to 15thNight
66%
780
7%
2145
7%
780
66%
780
19%
1587
September16th to endNight
65%
777
15%
2145
16%
777
66%
777
24%
1504
October1st to 15thNight
66%
780
27%
2179
25%
780
70%
780
34%
1330
October16th to endNight
57%
832
29%
2496
25%
832
64%
832
35%
1434
November1st to 15thNight
59%
820
30%
2461
24%
820
69%
820
40%
1343
November16th to endNight
52%
840
30%
2632
23%
840
63%
840
34%
1517
December1st to 15thNight
49%
840
27%
2730
21%
840
60%
840
31%
1601
December16th to endNight
56%
896
26%
2912
25%
896
61%
896
31%
1668

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%426%6%46%6%7%9%38%
54180
Night
7%425%5%35%5%6%9%44%
53863
TransparencyDay
39%8%14%18%14%5%
53881
Night
34%7%16%20%15%5%
53666
SeeingDay
8%315%24%25%22%
7918
Night
8%318%33%27%9%
18142

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
9%7%25%5%245%6%11%40%
1881
16th to endDay
9%4244345%5%7%46%
2134
February1st to 15thDay
11%5%2442445%8%45%
2050
16th to endDay
5%5%14424448%52%
1874
March1st to 15thDay
42144335%6%8%54%
2310
16th to endDay
7%4244345%5%7%51%
2463
April1st to 15thDay
6%2245%35%5%6%9%47%
2302
16th to endDay
4325%335%5%6%8%51%
2412
May1st to 15thDay
6%3144345%6%8%51%
2656
16th to endDay
7%426%7%47%7%7%8%35%
2639
June1st to 15thDay
10%6%37%6%47%8%9%9%25%
2535
16th to endDay
7%437%9%5%9%8%9%11%23%
2535
July1st to 15thDay
7%5%26%9%5%11%10%9%9%21%
2535
16th to endDay
6%6%48%9%5%9%8%9%10%21%
2673
August1st to 15thDay
6%428%9%7%8%9%9%11%21%
2413
16th to endDay
9%6%37%8%6%9%7%8%9%23%
2341
September1st to 15thDay
7%6%28%8%49%9%9%10%23%
2145
16th to endDay
8%7%28%8%46%7%8%9%27%
2145
October1st to 15thDay
5%426%7%5%7%7%5%8%38%
2109
16th to endDay
8%42442446%8%48%
2080
November1st to 15thDay
6%314435%5%5%8%51%
2057
16th to endDay
7%425%5%345%5%7%47%
1985
December1st to 15thDay
8%5%25%5%35%6%5%9%42%
1890
16th to endDay
7%424435%6%7%9%45%
2016
January1st to 15thNight
8%6%26%435%45%8%43%
2717
16th to endNight
12%5%245%3445%7%43%
2791
February1st to 15thNight
10%5%244235%5%7%48%
2463
16th to endNight
7%424434448%50%
2169
March1st to 15thNight
432443445%8%54%
2310
16th to endNight
6%314323447%55%
2464
April1st to 15thNight
5%22442446%9%53%
2306
16th to endNight
5%41433445%7%56%
2159
May1st to 15thNight
431332446%9%56%
1851
16th to endNight
6%314435%5%6%9%49%
1826
June1st to 15thNight
9%5%35%6%35%5%7%12%36%
1755
16th to endNight
6%426%6%47%7%9%12%32%
1755
July1st to 15thNight
6%435%5%47%9%9%13%30%
1755
16th to endNight
45%36%8%48%8%9%12%28%
1847
August1st to 15thNight
4336%6%36%7%9%12%34%
1795
16th to endNight
7%6%37%6%36%6%8%11%31%
2200
September1st to 15thNight
6%5%27%7%5%7%8%8%13%27%
2145
16th to endNight
7%6%28%6%46%5%8%10%33%
2145
October1st to 15thNight
5%415%5%25%5%5%8%48%
2179
16th to endNight
8%425%42335%8%51%
2496
November1st to 15thNight
5%31442445%8%54%
2461
16th to endNight
6%415%5%345%5%7%49%
2632
December1st to 15thNight
9%425%5%2445%8%47%
2730
16th to endNight
7%424435%6%6%9%46%
2912

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%49%23%19%5%
1882
16th to endDay
35%47%19%24%8%
2134
February1st to 15thDay
35%5%9%19%19%11%
2052
16th to endDay
30%5%11%18%23%10%
1874
March1st to 15thDay
25%5%11%26%21%10%
2310
16th to endDay
31%5%9%23%22%9%
2464
April1st to 15thDay
30%6%13%20%22%6%
2302
16th to endDay
27%6%9%22%25%8%
2412
May1st to 15thDay
27%8%11%23%20%8%
2656
16th to endDay
41%9%11%19%15%2
2643
June1st to 15thDay
47%10%18%18%4
2535
16th to endDay
47%13%22%13%2
2535
July1st to 15thDay
53%13%24%7%1
2396
16th to endDay
51%13%23%11%1
2518
August1st to 15thDay
50%12%27%8%
2400
16th to endDay
53%12%21%12%
2341
September1st to 15thDay
49%14%21%11%2
2145
16th to endDay
47%8%17%18%6%1
2145
October1st to 15thDay
39%9%8%18%15%8%
2109
16th to endDay
33%5%9%17%21%13%
2080
November1st to 15thDay
30%47%26%21%8%
2057
16th to endDay
34%5%8%21%19%11%
1985
December1st to 15thDay
37%5%10%23%16%6%
1890
16th to endDay
33%5%12%23%19%6%
2016
January1st to 15thNight
38%410%22%18%5%
2717
16th to endNight
38%38%19%20%8%
2791
February1st to 15thNight
34%49%19%20%11%
2472
16th to endNight
31%413%19%23%7%
2169
March1st to 15thNight
27%412%27%20%8%
2310
16th to endNight
28%411%26%21%8%
2464
April1st to 15thNight
26%5%17%25%20%5%
2306
16th to endNight
27%410%25%24%7%
2159
May1st to 15thNight
23%6%14%27%20%7%
1852
16th to endNight
30%8%19%22%17%2
1828
June1st to 15thNight
40%9%23%20%6%
1755
16th to endNight
39%12%27%16%4
1755
July1st to 15thNight
41%15%32%8%1
1665
16th to endNight
42%14%30%11%1
1739
August1st to 15thNight
36%14%37%10%
1784
16th to endNight
44%12%26%14%1
2200
September1st to 15thNight
44%14%24%12%2
2145
16th to endNight
44%8%19%20%42
2145
October1st to 15thNight
32%7%12%22%18%6%
2179
16th to endNight
32%39%19%24%10%
2496
November1st to 15thNight
28%311%23%23%8%
2461
16th to endNight
32%5%8%23%19%11%
2632
December1st to 15thNight
36%311%25%17%5%
2730
16th to endNight
32%6%12%25%16%6%
2912

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
10%10%35%30%12%1
180
16th to endDay
10%13%39%29%6%1
192
February1st to 15thDay
9%9%22%32%21%5%
180
16th to endDay
9%235%29%22%1
193
March1st to 15thDay
38%35%36%13%1
390
16th to endDay
10%7%23%33%21%2
416
April1st to 15thDay
6%5%26%29%26%5%
390
16th to endDay
5%5%18%31%30%8%
379
May1st to 15thDay
8%214%32%27%14%
388
16th to endDay
9%28%21%29%28%
395
June1st to 15thDay
14%1411%30%37%
375
16th to endDay
5%210%25%54%
375
July1st to 15thDay
45%26%63%
365
16th to endDay
11%212%26%46%
390
August1st to 15thDay
6%1110%28%51%
358
16th to endDay
10%2210%26%48%
396
September1st to 15thDay
12%2315%28%37%
375
16th to endDay
9%1116%36%35%
374
October1st to 15thDay
5%49%33%34%12%
375
16th to endDay
10%321%32%25%7%
400
November1st to 15thDay
5%218%33%31%7%
385
16th to endDay
5%426%43%16%3
275
December1st to 15thDay
8%9%42%25%11%2
180
16th to endDay
45%20%40%23%6%
192
January1st to 15thNight
11%7%23%39%17%
840
16th to endNight
15%7%28%36%11%
896
February1st to 15thNight
13%5%28%35%16%
824
16th to endNight
7%5%29%42%15%
735
March1st to 15thNight
5%5%34%41%12%
840
16th to endNight
7%5%26%42%16%1
896
April1st to 15thNight
6%326%41%19%1
838
16th to endNight
8%326%40%20%
817
May1st to 15thNight
6%112%46%29%3
617
16th to endNight
7%12%36%35%7%
611
June1st to 15thNight
11%423%43%16%
585
16th to endNight
6%213%41%35%
585
July1st to 15thNight
7%16%44%39%
555
16th to endNight
5%117%44%39%
612
August1st to 15thNight
48%46%39%
575
16th to endNight
9%1313%38%32%
751
September1st to 15thNight
10%1421%42%20%
780
16th to endNight
9%1329%40%15%
777
October1st to 15thNight
7%212%41%30%5%
780
16th to endNight
9%221%35%29%2
832
November1st to 15thNight
6%124%40%23%3
820
16th to endNight
7%326%42%17%1
840
December1st to 15thNight
10%328%35%20%
840
16th to endNight
7%5%21%40%23%1
896
Page generated at 2019-05-12 00:31:05. Version ac04

Copyright 2019 A. Danko


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