Fort Myers Beach
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Myers Beach clear sky chart from 2005-11-06 to 2024-11-12.

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 Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(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

By Month

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 Forecast	Data Points
Cloud Cover	Day	6% 4 2 6% 5% 5% 6% 5% 8% 10% 43%	100824
	Night	7% 5% 2 7% 5% 5% 6% 5% 7% 10% 41%	98309
Transparency	Day	19% 50% 12% 12% 6% 1	104612
	Night	21% 50% 10% 11% 6% 1	102660
Seeing	Day	6% 3 14% 27% 29% 21%	15681
	Night	8% 3 15% 33% 30% 12%	25747

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	9% 8% 3 7% 4 4 5% 3 5% 8% 42%	2836
	11th to 20th	Day	16% 9% 3 7% 4 5% 4 4 6% 9% 33%	2840
	21st to end	Day	7% 7% 3 7% 5% 5% 5% 5% 6% 8% 42%	3416
February	1st to 10th	Day	8% 5% 2 6% 4 4 3 4 6% 9% 50%	1900
	11th to 20th	Day	5% 3 1 4 3 4 3 3 5% 8% 61%	1848
	21st to end	Day	5% 4 1 4 3 4 4 3 5% 10% 58%	1685
March	1st to 10th	Day	4 4 2 6% 5% 6% 6% 6% 8% 8% 45%	3435
	11th to 20th	Day	4 3 1 4 3 4 4 4 8% 10% 57%	3480
	21st to end	Day	8% 4 2 4 3 3 3 3 5% 7% 58%	3815
April	1st to 10th	Day	3 2 1 4 3 3 4 4 6% 11% 59%	2090
	11th to 20th	Day	5% 4 1 4 4 4 4 4 6% 10% 55%	2066
	21st to end	Day	4 3 1 4 3 4 4 4 6% 10% 57%	2247
May	1st to 10th	Day	2 1 2 1 2 2 2 5% 8% 74%	3911
	11th to 20th	Day	5% 4 2 5% 4 4 5% 4 7% 11% 48%	4081
	21st to end	Day	4 3 1 3 3 4 4 3 5% 8% 61%	4476
June	1st to 10th	Day	11% 7% 3 6% 6% 5% 7% 5% 9% 11% 31%	2470
	11th to 20th	Day	8% 5% 1 6% 6% 6% 8% 5% 10% 13% 31%	2470
	21st to end	Day	6% 5% 2 8% 6% 7% 8% 7% 11% 12% 27%	2470
July	1st to 10th	Day	5% 4 2 7% 6% 7% 7% 8% 10% 12% 31%	4120
	11th to 20th	Day	4 4 2 7% 6% 7% 8% 8% 11% 13% 29%	4120
	21st to end	Day	4 3 2 6% 6% 7% 8% 8% 10% 14% 31%	4466
August	1st to 10th	Day	4 4 3 9% 8% 8% 8% 6% 10% 12% 29%	4058
	11th to 20th	Day	4 3 2 7% 5% 7% 6% 6% 11% 15% 33%	3601
	21st to end	Day	6% 5% 2 7% 7% 6% 7% 6% 10% 14% 30%	3828
September	1st to 10th	Day	5% 4 2 7% 7% 7% 9% 6% 11% 13% 29%	2090
	11th to 20th	Day	7% 6% 2 7% 7% 8% 7% 6% 9% 10% 30%	2090
	21st to end	Day	8% 5% 3 7% 6% 7% 7% 6% 10% 12% 30%	2090
October	1st to 10th	Day	7% 6% 3 8% 6% 6% 6% 5% 8% 10% 36%	2090
	11th to 20th	Day	7% 6% 2 6% 4 5% 5% 5% 8% 9% 43%	1924
	21st to end	Day	8% 4 2 6% 3 5% 5% 5% 7% 7% 49%	2090
November	1st to 10th	Day	6% 5% 2 4 3 4 4 3 7% 8% 54%	1957
	11th to 20th	Day	7% 4 2 6% 4 4 5% 5% 7% 10% 46%	1910
	21st to end	Day	5% 4 1 4 5% 4 4 4 6% 9% 52%	1867
December	1st to 10th	Day	6% 5% 2 5% 4 4 4 4 6% 8% 52%	1710
	11th to 20th	Day	7% 5% 2 5% 5% 5% 4 5% 7% 9% 47%	2153
	21st to end	Day	9% 5% 2 8% 6% 5% 6% 5% 6% 10% 37%	3124
January	1st to 10th	Night	7% 6% 3 8% 5% 5% 6% 5% 8% 11% 37%	4109
	11th to 20th	Night	15% 10% 3 8% 6% 5% 5% 4 7% 8% 28%	4120
	21st to end	Night	7% 6% 3 9% 5% 5% 5% 5% 7% 9% 39%	4235
February	1st to 10th	Night	9% 7% 2 6% 4 4 4 4 5% 7% 48%	2280
	11th to 20th	Night	7% 5% 2 4 3 4 3 3 6% 8% 55%	2218
	21st to end	Night	5% 3 2 4 3 4 4 3 6% 7% 59%	1766
March	1st to 10th	Night	6% 5% 2 9% 6% 6% 6% 5% 6% 8% 42%	3418
	11th to 20th	Night	4 4 2 4 3 4 4 4 6% 12% 52%	3480
	21st to end	Night	6% 5% 2 5% 3 4 4 4 6% 9% 52%	3817
April	1st to 10th	Night	5% 2 1 4 3 3 4 4 7% 11% 55%	2090
	11th to 20th	Night	4 3 1 5% 5% 3 4 4 7% 10% 52%	2063
	21st to end	Night	4 4 2 5% 4 5% 5% 5% 7% 8% 53%	1933
May	1st to 10th	Night	4 4 1 6% 4 5% 5% 4 5% 9% 53%	3012
	11th to 20th	Night	5% 3 2 4 4 4 5% 5% 6% 10% 54%	2812
	21st to end	Night	4 4 1 4 4 4 4 4 6% 8% 58%	3079
June	1st to 10th	Night	11% 6% 3 7% 6% 5% 7% 5% 9% 9% 32%	1710
	11th to 20th	Night	6% 6% 2 6% 5% 6% 7% 7% 8% 13% 34%	1710
	21st to end	Night	5% 5% 3 7% 7% 7% 8% 6% 9% 13% 29%	1710
July	1st to 10th	Night	6% 5% 3 9% 8% 7% 8% 5% 8% 12% 29%	2840
	11th to 20th	Night	4 6% 3 9% 7% 8% 9% 7% 11% 13% 23%	2840
	21st to end	Night	4 6% 3 11% 8% 8% 8% 7% 10% 11% 22%	3087
August	1st to 10th	Night	5% 5% 3 10% 7% 7% 7% 6% 9% 12% 30%	2851
	11th to 20th	Night	4 5% 2 8% 7% 7% 8% 7% 11% 14% 26%	3195
	21st to end	Night	6% 5% 3 8% 6% 6% 8% 7% 11% 16% 25%	3828
September	1st to 10th	Night	4 5% 2 8% 7% 6% 9% 7% 10% 13% 28%	2090
	11th to 20th	Night	7% 7% 3 8% 6% 6% 7% 5% 9% 12% 30%	2090
	21st to end	Night	10% 7% 3 9% 6% 7% 7% 5% 8% 10% 28%	2090
October	1st to 10th	Night	8% 6% 3 8% 5% 5% 6% 5% 7% 9% 39%	2090
	11th to 20th	Night	7% 5% 3 8% 6% 5% 5% 4 6% 8% 44%	2252
	21st to end	Night	8% 5% 2 6% 4 5% 5% 4 6% 8% 46%	2508
November	1st to 10th	Night	7% 5% 2 5% 4 4 4 4 5% 8% 51%	2341
	11th to 20th	Night	8% 6% 2 6% 4 4 4 4 6% 8% 48%	2293
	21st to end	Night	7% 5% 2 6% 4 4 4 4 6% 9% 48%	2308
December	1st to 10th	Night	6% 4 2 5% 4 4 4 5% 6% 9% 50%	2470
	11th to 20th	Night	8% 7% 2 5% 4 4 4 3 5% 9% 49%	3042
	21st to end	Night	9% 7% 3 7% 5% 5% 6% 5% 7% 10% 36%	4532

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	29% 39% 6% 15% 10% 2	2837
	11th to 20th	Day	36% 41% 6% 9% 8% 1	2840
	21st to end	Day	25% 42% 5% 14% 13% 1	3416
February	1st to 10th	Day	9% 66% 7% 10% 5% 2	1900
	11th to 20th	Day	7% 64% 3 9% 12% 5%	1858
	21st to end	Day	9% 66% 7% 7% 7% 2	1685
March	1st to 10th	Day	24% 47% 12% 11% 4 1	3435
	11th to 20th	Day	10% 45% 15% 19% 8% 2	3480
	21st to end	Day	17% 42% 6% 19% 9% 7%	3815
April	1st to 10th	Day	6% 66% 7% 13% 6% 2	2090
	11th to 20th	Day	9% 67% 7% 8% 7% 3	2066
	21st to end	Day	9% 66% 5% 9% 11% 1	2247
May	1st to 10th	Day	5% 42% 9% 25% 15% 3	3946
	11th to 20th	Day	16% 44% 13% 23% 5%	4085
	21st to end	Day	7% 42% 9% 29% 12%	4489
June	1st to 10th	Day	17% 69% 8% 6%	2470
	11th to 20th	Day	18% 71% 8% 3	2470
	21st to end	Day	14% 70% 10% 5%	2470
July	1st to 10th	Day	25% 44% 22% 8%	4055
	11th to 20th	Day	26% 46% 24% 4	4051
	21st to end	Day	24% 45% 24% 7%	4324
August	1st to 10th	Day	29% 44% 19% 6% 2	4045
	11th to 20th	Day	21% 46% 22% 10% 1	3637
	21st to end	Day	24% 45% 25% 6%	3828
September	1st to 10th	Day	17% 67% 11% 5%	2090
	11th to 20th	Day	15% 65% 11% 7% 2	2090
	21st to end	Day	16% 66% 10% 6% 3 1	2090
October	1st to 10th	Day	35% 41% 12% 9% 3	3480
	11th to 20th	Day	19% 40% 10% 17% 13% 1	3177
	21st to end	Day	17% 38% 6% 22% 14% 3	3428
November	1st to 10th	Day	12% 58% 9% 13% 7% 2	1957
	11th to 20th	Day	17% 62% 5% 8% 5% 3	1910
	21st to end	Day	12% 62% 6% 9% 8% 3	1867
December	1st to 10th	Day	14% 61% 6% 12% 6% 1	1710
	11th to 20th	Day	16% 50% 4 12% 9% 8%	2150
	21st to end	Day	31% 41% 10% 13% 5%	3124
January	1st to 10th	Night	28% 41% 8% 12% 10% 1	4109
	11th to 20th	Night	39% 42% 6% 9% 4 1	4120
	21st to end	Night	26% 41% 4 12% 15% 2	4235
February	1st to 10th	Night	12% 66% 5% 11% 5% 1	2280
	11th to 20th	Night	7% 64% 3 9% 11% 6%	2219
	21st to end	Night	8% 65% 6% 7% 11% 3	1766
March	1st to 10th	Night	30% 46% 9% 10% 5% 1	3418
	11th to 20th	Night	14% 45% 15% 17% 9% 1	3480
	21st to end	Night	18% 43% 7% 13% 13% 5%	3817
April	1st to 10th	Night	7% 66% 6% 14% 5% 2	2090
	11th to 20th	Night	7% 67% 8% 8% 7% 2	2063
	21st to end	Night	9% 66% 7% 9% 8% 1	1933
May	1st to 10th	Night	17% 46% 9% 19% 5% 3	3042
	11th to 20th	Night	12% 43% 13% 26% 5%	2813
	21st to end	Night	8% 42% 8% 27% 14%	3087
June	1st to 10th	Night	15% 68% 8% 9%	1710
	11th to 20th	Night	16% 70% 10% 4	1710
	21st to end	Night	14% 69% 11% 5% 1	1710
July	1st to 10th	Night	30% 43% 20% 7%	2795
	11th to 20th	Night	30% 47% 19% 3	2786
	21st to end	Night	35% 44% 15% 6%	2988
August	1st to 10th	Night	28% 44% 18% 7% 4	2840
	11th to 20th	Night	25% 47% 20% 7%	3225
	21st to end	Night	24% 48% 25% 3 1	3828
September	1st to 10th	Night	17% 67% 11% 6%	2090
	11th to 20th	Night	15% 65% 13% 6% 1	2090
	21st to end	Night	17% 67% 8% 6% 3	2090
October	1st to 10th	Night	40% 41% 11% 6% 2	3480
	11th to 20th	Night	23% 40% 9% 13% 14% 1	3738
	21st to end	Night	21% 38% 6% 20% 13% 3	4120
November	1st to 10th	Night	12% 58% 8% 12% 7% 2	2341
	11th to 20th	Night	16% 62% 5% 8% 6% 3	2293
	21st to end	Night	13% 61% 6% 8% 9% 3	2308
December	1st to 10th	Night	14% 61% 6% 13% 6%	2470
	11th to 20th	Night	15% 50% 4 13% 10% 8%	3044
	21st to end	Night	30% 42% 12% 11% 5% 1	4532

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
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	9% 6% 31% 36% 17% 1	270
	11th to 20th	Day	9% 9% 27% 34% 17% 4	270
	21st to end	Day	9% 11% 34% 36% 9%	297
February	1st to 10th	Day	5% 8% 23% 37% 24% 3	270
	11th to 20th	Day	5% 4 21% 44% 20% 4	270
	21st to end	Day	5% 4 21% 42% 26% 3	340
March	1st to 10th	Day	3 3 32% 40% 20% 2	460
	11th to 20th	Day	5% 4 25% 37% 25% 3	460
	21st to end	Day	4 2 22% 43% 25% 3	506
April	1st to 10th	Day	3 5% 26% 41% 20% 5%	460
	11th to 20th	Day	6% 5% 20% 40% 26% 4	452
	21st to end	Day	5% 3 17% 38% 34% 4	460
May	1st to 10th	Day	4 11% 40% 33% 13%	463
	11th to 20th	Day	9% 1 14% 32% 29% 15%	487
	21st to end	Day	7% 1 8% 22% 37% 25%	529
June	1st to 10th	Day	12% 2 8% 19% 37% 22%	490
	11th to 20th	Day	9% 3 6% 16% 31% 35%	490
	21st to end	Day	4 3 11% 31% 50%	490
July	1st to 10th	Day	5% 1 1 8% 31% 54%	485
	11th to 20th	Day	4 1 2 10% 32% 52%	484
	21st to end	Day	6% 2 2 11% 30% 48%	532
August	1st to 10th	Day	5% 3 10% 33% 48%	486
	11th to 20th	Day	5% 3 7% 34% 50%	479
	21st to end	Day	10% 1 6% 14% 32% 38%	539
September	1st to 10th	Day	5% 2 3 12% 32% 46%	490
	11th to 20th	Day	6% 1 6% 14% 36% 37%	490
	21st to end	Day	7% 1 5% 16% 38% 34%	490
October	1st to 10th	Day	9% 2 10% 30% 36% 13%	490
	11th to 20th	Day	7% 4 12% 31% 32% 13%	490
	21st to end	Day	7% 2 17% 31% 33% 10%	539
November	1st to 10th	Day	7% 2 17% 30% 34% 9%	495
	11th to 20th	Day	9% 3 19% 36% 24% 8%	464
	21st to end	Day	5% 4 18% 41% 28% 4	427
December	1st to 10th	Day	7% 3 24% 34% 24% 8%	270
	11th to 20th	Day	6% 7% 19% 36% 26% 5%	270
	21st to end	Day	5% 6% 24% 32% 27% 6%	297
January	1st to 10th	Night	9% 5% 23% 40% 22% 2	760
	11th to 20th	Night	10% 5% 24% 41% 19% 1	760
	21st to end	Night	10% 6% 28% 41% 16%	836
February	1st to 10th	Night	10% 6% 24% 42% 18% 1	760
	11th to 20th	Night	7% 5% 22% 43% 22% 1	743
	21st to end	Night	6% 3 19% 49% 23% 1	628
March	1st to 10th	Night	4 4 26% 45% 20% 1	760
	11th to 20th	Night	7% 2 22% 42% 26%	760
	21st to end	Night	5% 3 23% 48% 21% 1	836
April	1st to 10th	Night	5% 2 20% 48% 24% 1	760
	11th to 20th	Night	4 4 21% 48% 21% 2	751
	21st to end	Night	5% 2 21% 47% 23% 2	760
May	1st to 10th	Night	3 2 12% 46% 34% 3	694
	11th to 20th	Night	7% 1 10% 39% 38% 3	561
	21st to end	Night	7% 1 7% 34% 44% 7%	617
June	1st to 10th	Night	13% 1 6% 21% 45% 14%	570
	11th to 20th	Night	6% 2 5% 13% 45% 30%	570
	21st to end	Night	4 1 3 12% 43% 38%	570
July	1st to 10th	Night	5% 1 3 8% 38% 45%	555
	11th to 20th	Night	5% 1 3 8% 40% 45%	552
	21st to end	Night	5% 2 9% 36% 47%	624
August	1st to 10th	Night	6% 1 2 10% 42% 38%	567
	11th to 20th	Night	6% 1 2 6% 39% 46%	620
	21st to end	Night	10% 1 7% 16% 39% 27%	836
September	1st to 10th	Night	6% 5% 15% 46% 28%	760
	11th to 20th	Night	10% 1 5% 16% 43% 24%	760
	21st to end	Night	13% 2 6% 20% 41% 19%	760
October	1st to 10th	Night	11% 3 10% 36% 33% 8%	760
	11th to 20th	Night	8% 3 14% 33% 35% 8%	760
	21st to end	Night	9% 3 17% 39% 27% 5%	836
November	1st to 10th	Night	8% 2 21% 39% 26% 4	780
	11th to 20th	Night	8% 3 22% 38% 25% 3	765
	21st to end	Night	9% 3 16% 43% 27% 1	760
December	1st to 10th	Night	8% 3 18% 40% 28% 3	760
	11th to 20th	Night	9% 4 20% 37% 28% 2	760
	21st to end	Night	9% 3 21% 39% 26% 2	836

Page generated at 2024-11-08 22:45:38. Version ac07

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