Eastern Florida State College
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Eastern Florida State College clear sky chart from 2005-11-06 to 2026-07-16.

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	7% 5% 2 7% 5% 6% 6% 5% 8% 11% 39%	137504
	Night	8% 6% 2 7% 5% 5% 5% 4 7% 9% 43%	135209
Transparency	Day	36% 10% 18% 20% 12% 4	141173
	Night	35% 9% 18% 21% 12% 5%	139612
Seeing	Day	8% 6% 21% 27% 23% 16%	18044
	Night	9% 4 18% 31% 29% 9%	28127

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	6% 5% 1 6% 4 4 4 3 5% 8% 55%	5258
	11th to 20th	Day	16% 10% 4 8% 5% 5% 4 4 5% 7% 32%	5280
	21st to end	Day	15% 5% 2 5% 4 4 4 4 6% 8% 43%	5780
February	1st to 10th	Day	11% 6% 2 6% 4 4 4 4 6% 8% 44%	2084
	11th to 20th	Day	5% 5% 2 5% 4 5% 4 3 7% 8% 51%	2071
	21st to end	Day	9% 5% 2 5% 4 4 4 5% 6% 7% 49%	1903
March	1st to 10th	Day	6% 5% 2 7% 5% 5% 5% 4 6% 10% 43%	5045
	11th to 20th	Day	4 3 1 4 4 4 4 3 5% 8% 61%	5090
	21st to end	Day	8% 5% 2 6% 4 5% 5% 4 7% 9% 44%	5586
April	1st to 10th	Day	5% 4 1 6% 5% 5% 5% 4 7% 9% 48%	2310
	11th to 20th	Day	7% 5% 2 7% 4 5% 6% 5% 6% 8% 44%	2392
	21st to end	Day	5% 4 2 4 4 5% 6% 5% 8% 10% 48%	2520
May	1st to 10th	Day	4 3 2 5% 5% 5% 6% 5% 8% 12% 47%	7113
	11th to 20th	Day	8% 5% 2 6% 5% 5% 5% 4 7% 10% 42%	7626
	21st to end	Day	5% 3 2 6% 6% 6% 7% 6% 9% 12% 39%	8391
June	1st to 10th	Day	11% 7% 3 8% 7% 6% 8% 6% 9% 11% 23%	2730
	11th to 20th	Day	7% 4 3 8% 7% 7% 9% 8% 10% 11% 27%	2730
	21st to end	Day	8% 6% 3 8% 7% 7% 8% 6% 9% 11% 27%	2730
July	1st to 10th	Day	6% 5% 3 8% 7% 7% 8% 7% 10% 14% 25%	6030
	11th to 20th	Day	4 4 2 7% 5% 6% 7% 5% 10% 14% 35%	5965
	21st to end	Day	4 5% 2 7% 5% 6% 7% 6% 9% 14% 36%	6424
August	1st to 10th	Day	4 5% 3 7% 6% 7% 8% 7% 10% 15% 27%	4234
	11th to 20th	Day	4 5% 2 7% 6% 7% 7% 7% 10% 12% 34%	3953
	21st to end	Day	7% 6% 2 9% 5% 7% 7% 7% 11% 15% 25%	4054
September	1st to 10th	Day	7% 7% 3 9% 8% 8% 8% 6% 9% 11% 22%	2200
	11th to 20th	Day	8% 7% 3 10% 7% 7% 9% 6% 9% 11% 24%	2200
	21st to end	Day	10% 6% 3 8% 8% 8% 7% 6% 9% 9% 27%	2200
October	1st to 10th	Day	12% 6% 3 9% 7% 6% 7% 6% 7% 9% 28%	2115
	11th to 20th	Day	7% 5% 2 7% 5% 6% 5% 4 7% 11% 42%	2000
	21st to end	Day	8% 4 2 6% 4 5% 4 4 7% 9% 46%	2200
November	1st to 10th	Day	8% 5% 2 7% 5% 5% 6% 5% 7% 11% 39%	2057
	11th to 20th	Day	8% 6% 2 7% 5% 5% 5% 4 7% 8% 44%	2100
	21st to end	Day	8% 6% 2 6% 6% 6% 5% 4 6% 11% 41%	2085
December	1st to 10th	Day	6% 4 2 6% 4 4 4 4 6% 8% 54%	3020
	11th to 20th	Day	9% 6% 3 7% 5% 6% 6% 5% 7% 11% 34%	3463
	21st to end	Day	9% 6% 3 7% 6% 6% 6% 5% 7% 8% 35%	4565
January	1st to 10th	Night	7% 5% 2 5% 3 3 4 3 5% 7% 57%	7635
	11th to 20th	Night	14% 9% 4 8% 5% 5% 4 4 6% 7% 33%	7680
	21st to end	Night	12% 6% 2 5% 4 4 4 4 5% 8% 47%	8401
February	1st to 10th	Night	9% 7% 2 6% 4 3 4 4 6% 7% 48%	2530
	11th to 20th	Night	10% 5% 1 5% 4 4 4 4 6% 8% 50%	2432
	21st to end	Night	8% 4 2 4 3 4 4 4 5% 7% 55%	1903
March	1st to 10th	Night	8% 6% 2 7% 5% 5% 5% 4 6% 7% 46%	5028
	11th to 20th	Night	5% 3 1 4 3 3 3 3 6% 10% 58%	5090
	21st to end	Night	7% 5% 3 6% 5% 4 5% 4 6% 8% 47%	5588
April	1st to 10th	Night	6% 4 2 5% 4 3 4 4 6% 9% 53%	2310
	11th to 20th	Night	5% 4 2 6% 4 4 5% 4 7% 9% 50%	2175
	21st to end	Night	5% 4 1 4 4 4 6% 4 6% 8% 54%	2100
May	1st to 10th	Night	4 3 2 6% 4 4 5% 5% 8% 11% 49%	5781
	11th to 20th	Night	8% 6% 3 7% 4 4 5% 4 7% 8% 44%	5234
	21st to end	Night	4 4 2 6% 5% 5% 6% 5% 9% 12% 41%	5761
June	1st to 10th	Night	10% 8% 2 9% 6% 6% 5% 6% 9% 10% 30%	1890
	11th to 20th	Night	6% 7% 3 8% 6% 6% 7% 6% 10% 13% 29%	1890
	21st to end	Night	6% 6% 2 8% 7% 5% 7% 5% 7% 12% 34%	1890
July	1st to 10th	Night	9% 8% 3 8% 5% 5% 7% 5% 9% 11% 30%	4148
	11th to 20th	Night	4 4 2 6% 5% 5% 6% 6% 9% 13% 41%	4102
	21st to end	Night	4 4 2 6% 5% 6% 6% 5% 9% 12% 40%	4427
August	1st to 10th	Night	4 5% 3 8% 6% 6% 7% 5% 9% 13% 34%	2915
	11th to 20th	Night	5% 5% 3 8% 5% 6% 6% 6% 10% 11% 37%	3062
	21st to end	Night	7% 6% 2 8% 6% 6% 7% 6% 10% 13% 30%	3838
September	1st to 10th	Night	7% 6% 3 9% 7% 7% 7% 6% 10% 13% 26%	2200
	11th to 20th	Night	9% 8% 4 11% 7% 6% 7% 5% 8% 10% 27%	2200
	21st to end	Night	9% 8% 4 8% 6% 6% 6% 6% 8% 10% 29%	2200
October	1st to 10th	Night	12% 7% 3 8% 5% 6% 5% 4 6% 9% 34%	2282
	11th to 20th	Night	7% 6% 2 6% 4 5% 5% 5% 6% 8% 47%	2400
	21st to end	Night	8% 5% 2 6% 4 4 4 4 7% 8% 47%	2640
November	1st to 10th	Night	8% 6% 2 7% 5% 4 6% 4 6% 8% 44%	2461
	11th to 20th	Night	7% 5% 2 7% 5% 4 5% 5% 7% 7% 45%	2520
	21st to end	Night	10% 6% 3 7% 5% 4 5% 5% 7% 9% 41%	2531
December	1st to 10th	Night	5% 3 1 4 4 4 5% 4 7% 8% 56%	4380
	11th to 20th	Night	12% 7% 3 7% 6% 4 5% 4 6% 8% 38%	4952
	21st to end	Night	10% 8% 3 8% 5% 5% 5% 4 6% 7% 38%	6633

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	28% 5% 11% 25% 23% 8%	5259
	11th to 20th	Day	51% 4 8% 16% 14% 6%	5280
	21st to end	Day	38% 6% 9% 24% 16% 6%	5780
February	1st to 10th	Day	36% 6% 11% 16% 22% 9%	2084
	11th to 20th	Day	28% 7% 12% 23% 22% 8%	2081
	21st to end	Day	32% 7% 12% 17% 25% 8%	1903
March	1st to 10th	Day	34% 10% 12% 18% 20% 5%	5045
	11th to 20th	Day	21% 6% 10% 28% 19% 15%	5090
	21st to end	Day	32% 8% 12% 26% 15% 7%	5586
April	1st to 10th	Day	29% 9% 15% 25% 16% 6%	2310
	11th to 20th	Day	34% 9% 11% 18% 21% 7%	2392
	21st to end	Day	27% 9% 13% 23% 23% 6%	2520
May	1st to 10th	Day	25% 9% 23% 28% 13% 2	7145
	11th to 20th	Day	33% 8% 19% 27% 11% 1	7630
	21st to end	Day	32% 11% 22% 26% 9%	8405
June	1st to 10th	Day	49% 12% 19% 15% 4	2730
	11th to 20th	Day	42% 16% 23% 17% 2	2730
	21st to end	Day	43% 16% 24% 13% 3	2730
July	1st to 10th	Day	42% 15% 29% 11% 2	5965
	11th to 20th	Day	34% 14% 38% 13% 1	5896
	21st to end	Day	34% 14% 28% 23% 1	6240
August	1st to 10th	Day	39% 17% 32% 10% 1	4221
	11th to 20th	Day	34% 17% 26% 15% 7%	3992
	21st to end	Day	42% 17% 28% 12% 2	4054
September	1st to 10th	Day	50% 17% 20% 10% 3	2200
	11th to 20th	Day	47% 17% 21% 12% 3	2200
	21st to end	Day	47% 13% 17% 12% 9% 2	2200
October	1st to 10th	Day	53% 11% 16% 11% 7% 2	3440
	11th to 20th	Day	31% 7% 9% 22% 26% 4	3240
	21st to end	Day	28% 6% 10% 24% 27% 6%	3538
November	1st to 10th	Day	35% 8% 13% 19% 18% 7%	2057
	11th to 20th	Day	36% 8% 10% 22% 17% 7%	2100
	21st to end	Day	36% 8% 11% 21% 18% 6%	2085
December	1st to 10th	Day	28% 5% 17% 28% 14% 9%	3020
	11th to 20th	Day	40% 8% 12% 18% 17% 5%	3460
	21st to end	Day	42% 8% 12% 20% 13% 4	4565
January	1st to 10th	Night	26% 5% 12% 27% 21% 9%	7636
	11th to 20th	Night	49% 5% 11% 17% 12% 6%	7680
	21st to end	Night	35% 6% 12% 24% 14% 9%	8401
February	1st to 10th	Night	34% 7% 12% 18% 19% 11%	2530
	11th to 20th	Night	30% 7% 12% 23% 19% 9%	2433
	21st to end	Night	26% 7% 14% 21% 25% 7%	1903
March	1st to 10th	Night	35% 8% 12% 21% 18% 7%	5028
	11th to 20th	Night	19% 8% 18% 24% 17% 13%	5090
	21st to end	Night	31% 8% 12% 26% 18% 4	5588
April	1st to 10th	Night	25% 8% 19% 26% 15% 7%	2310
	11th to 20th	Night	28% 8% 14% 22% 21% 6%	2175
	21st to end	Night	25% 8% 15% 25% 21% 6%	2100
May	1st to 10th	Night	26% 9% 24% 28% 11% 2	5811
	11th to 20th	Night	34% 9% 21% 27% 9%	5235
	21st to end	Night	31% 11% 24% 25% 8%	5771
June	1st to 10th	Night	45% 11% 23% 17% 5%	1890
	11th to 20th	Night	41% 14% 22% 20% 3	1890
	21st to end	Night	42% 12% 26% 17% 4	1890
July	1st to 10th	Night	45% 14% 27% 14% 1	4105
	11th to 20th	Night	32% 15% 41% 12%	4051
	21st to end	Night	33% 15% 29% 23% 1	4297
August	1st to 10th	Night	38% 16% 33% 11% 2	2904
	11th to 20th	Night	36% 14% 29% 15% 7%	3089
	21st to end	Night	42% 15% 32% 10% 1	3838
September	1st to 10th	Night	44% 20% 21% 12% 3	2200
	11th to 20th	Night	48% 15% 21% 14% 2	2200
	21st to end	Night	45% 13% 17% 15% 8% 2	2200
October	1st to 10th	Night	56% 10% 14% 12% 6% 2	3737
	11th to 20th	Night	33% 7% 10% 24% 21% 4	3899
	21st to end	Night	30% 7% 10% 22% 25% 6%	4252
November	1st to 10th	Night	35% 7% 14% 18% 18% 7%	2461
	11th to 20th	Night	34% 8% 12% 22% 16% 7%	2520
	21st to end	Night	36% 7% 12% 21% 18% 5%	2531
December	1st to 10th	Night	24% 6% 18% 31% 11% 10%	4380
	11th to 20th	Night	41% 7% 14% 17% 13% 8%	4954
	21st to end	Night	42% 8% 13% 20% 11% 5%	6633

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	11% 11% 43% 25% 8% 2	330
	11th to 20th	Day	8% 15% 41% 23% 10% 3	330
	21st to end	Day	16% 15% 43% 21% 5%	363
February	1st to 10th	Day	11% 12% 36% 26% 12% 2	330
	11th to 20th	Day	8% 10% 37% 31% 10% 3	353
	21st to end	Day	9% 10% 31% 32% 16% 2	446
March	1st to 10th	Day	7% 12% 33% 34% 12% 1	540
	11th to 20th	Day	9% 11% 30% 31% 16% 2	540
	21st to end	Day	7% 9% 28% 32% 20% 4	594
April	1st to 10th	Day	7% 9% 34% 29% 14% 5%	540
	11th to 20th	Day	6% 11% 27% 30% 19% 6%	532
	21st to end	Day	6% 5% 27% 33% 21% 9%	540
May	1st to 10th	Day	5% 6% 24% 33% 23% 9%	543
	11th to 20th	Day	10% 4 21% 28% 23% 14%	567
	21st to end	Day	8% 3 13% 26% 29% 20%	617
June	1st to 10th	Day	11% 4 12% 28% 27% 18%	570
	11th to 20th	Day	6% 2 7% 25% 31% 29%	570
	21st to end	Day	4 2 7% 16% 32% 39%	570
July	1st to 10th	Day	6% 1 5% 14% 29% 45%	565
	11th to 20th	Day	5% 1 4 14% 36% 40%	544
	21st to end	Day	6% 1 6% 20% 30% 37%	576
August	1st to 10th	Day	5% 3 7% 17% 32% 36%	526
	11th to 20th	Day	3 1 6% 16% 29% 45%	519
	21st to end	Day	9% 2 6% 20% 32% 31%	583
September	1st to 10th	Day	9% 4 7% 19% 27% 34%	530
	11th to 20th	Day	10% 3 9% 25% 29% 25%	530
	21st to end	Day	8% 3 12% 23% 33% 22%	530
October	1st to 10th	Day	15% 4 18% 32% 23% 8%	530
	11th to 20th	Day	5% 5% 21% 34% 29% 7%	530
	21st to end	Day	6% 4 25% 37% 22% 6%	583
November	1st to 10th	Day	9% 8% 20% 36% 21% 6%	535
	11th to 20th	Day	10% 7% 28% 31% 20% 4	540
	21st to end	Day	9% 6% 26% 38% 19% 2	525
December	1st to 10th	Day	5% 10% 38% 31% 13% 2	330
	11th to 20th	Day	9% 7% 35% 34% 12% 2	330
	21st to end	Day	6% 10% 32% 33% 16% 3	363
January	1st to 10th	Night	12% 8% 28% 34% 16% 1	840
	11th to 20th	Night	11% 7% 29% 37% 15% 1	840
	21st to end	Night	11% 9% 34% 35% 10%	924
February	1st to 10th	Night	11% 8% 26% 38% 16% 1	840
	11th to 20th	Night	11% 7% 30% 36% 15% 1	823
	21st to end	Night	9% 5% 31% 42% 12%	692
March	1st to 10th	Night	5% 9% 31% 41% 13% 1	840
	11th to 20th	Night	8% 7% 28% 40% 17% 2	840
	21st to end	Night	6% 6% 30% 39% 18% 1	924
April	1st to 10th	Night	6% 6% 28% 40% 18% 1	840
	11th to 20th	Night	7% 5% 24% 42% 22% 1	831
	21st to end	Night	5% 3 22% 46% 21% 2	840
May	1st to 10th	Night	5% 3 19% 47% 25% 1	826
	11th to 20th	Night	8% 3 14% 35% 35% 5%	621
	21st to end	Night	8% 2 6% 31% 43% 10%	683
June	1st to 10th	Night	12% 2 6% 27% 44% 9%	630
	11th to 20th	Night	7% 2 6% 19% 46% 20%	630
	21st to end	Night	6% 1 3 17% 49% 24%	630
July	1st to 10th	Night	8% 2 4 15% 45% 27%	615
	11th to 20th	Night	7% 1 2 11% 47% 32%	597
	21st to end	Night	5% 2 2 11% 50% 30%	657
August	1st to 10th	Night	4 1 4 12% 50% 29%	597
	11th to 20th	Night	4 1 3 11% 48% 33%	703
	21st to end	Night	10% 1 6% 19% 41% 23%	880
September	1st to 10th	Night	10% 2 6% 17% 43% 23%	800
	11th to 20th	Night	11% 3 7% 21% 43% 17%	800
	21st to end	Night	12% 2 8% 21% 42% 15%	800
October	1st to 10th	Night	14% 3 14% 31% 33% 6%	800
	11th to 20th	Night	8% 4 13% 32% 38% 6%	800
	21st to end	Night	11% 3 19% 34% 29% 4	880
November	1st to 10th	Night	9% 4 21% 33% 28% 5%	820
	11th to 20th	Night	7% 6% 22% 38% 25% 3	840
	21st to end	Night	11% 4 24% 38% 21% 2	840
December	1st to 10th	Night	7% 4 25% 37% 25% 2	840
	11th to 20th	Night	9% 7% 25% 35% 22% 2	840
	21st to end	Night	10% 5% 27% 36% 21% 2	924

Page generated at 2026-07-13 03:14:51. Version ac07

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