Orlando
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Orlando clear sky chart from 2005-11-06 to 2025-08-05.

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	8% 5% 2 7% 6% 6% 6% 5% 7% 10% 38%	125418
	Night	9% 6% 2 7% 5% 5% 5% 4 6% 9% 43%	122634
Transparency	Day	39% 8% 16% 19% 13% 5%	129113
	Night	37% 8% 16% 21% 14% 5%	126995
Seeing	Day	9% 7% 21% 26% 22% 16%	16618
	Night	9% 5% 22% 32% 24% 7%	26680

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	8% 6% 2 5% 4 4 4 4 5% 7% 54%	4056
	11th to 20th	Day	19% 9% 4 8% 5% 5% 5% 4 4 6% 31%	4060
	21st to end	Day	14% 6% 2 6% 4 3 3 3 6% 9% 45%	4558
February	1st to 10th	Day	12% 6% 2 6% 5% 4 5% 4 6% 7% 43%	2000
	11th to 20th	Day	7% 5% 2 6% 4 5% 5% 3 6% 6% 51%	1948
	21st to end	Day	9% 5% 2 6% 5% 5% 5% 4 6% 7% 46%	1780
March	1st to 10th	Day	7% 6% 3 8% 5% 5% 5% 4 6% 9% 44%	4935
	11th to 20th	Day	4 3 1 5% 4 3 3 3 5% 8% 60%	4980
	21st to end	Day	8% 5% 2 6% 5% 4 5% 4 6% 8% 46%	5465
April	1st to 10th	Day	6% 4 2 5% 5% 5% 5% 5% 7% 8% 48%	2200
	11th to 20th	Day	8% 5% 2 6% 5% 5% 6% 4 7% 9% 43%	2231
	21st to end	Day	4 4 2 5% 4 5% 5% 5% 7% 10% 49%	2400
May	1st to 10th	Day	4 3 2 6% 6% 5% 6% 5% 8% 11% 45%	5679
	11th to 20th	Day	9% 5% 2 6% 4 5% 5% 4 7% 9% 44%	5861
	21st to end	Day	5% 4 2 6% 5% 6% 6% 6% 8% 11% 42%	6433
June	1st to 10th	Day	12% 7% 3 10% 8% 7% 8% 5% 8% 9% 23%	2600
	11th to 20th	Day	7% 6% 3 9% 9% 8% 9% 7% 8% 10% 26%	2600
	21st to end	Day	9% 7% 3 9% 9% 7% 7% 6% 8% 8% 26%	2600
July	1st to 10th	Day	8% 6% 3 10% 8% 8% 9% 7% 10% 14% 18%	5900
	11th to 20th	Day	4 5% 3 8% 7% 7% 8% 6% 10% 14% 28%	5900
	21st to end	Day	5% 5% 2 7% 7% 7% 8% 7% 8% 13% 30%	6424
August	1st to 10th	Day	5% 7% 3 9% 8% 8% 8% 6% 9% 12% 26%	4156
	11th to 20th	Day	4 4 3 8% 7% 8% 8% 6% 9% 12% 30%	3872
	21st to end	Day	8% 7% 3 10% 8% 8% 8% 6% 9% 12% 22%	3828
September	1st to 10th	Day	8% 7% 3 10% 9% 8% 8% 8% 10% 9% 22%	2090
	11th to 20th	Day	11% 8% 3 10% 8% 9% 8% 6% 7% 10% 22%	2090
	21st to end	Day	10% 7% 3 9% 7% 7% 8% 6% 7% 10% 27%	2090
October	1st to 10th	Day	13% 6% 3 9% 7% 7% 6% 5% 6% 8% 30%	2051
	11th to 20th	Day	7% 5% 2 7% 6% 5% 5% 4 7% 8% 44%	1900
	21st to end	Day	6% 4 2 7% 5% 5% 5% 5% 7% 9% 46%	2090
November	1st to 10th	Day	7% 5% 2 6% 5% 4 6% 5% 7% 9% 44%	1957
	11th to 20th	Day	8% 6% 2 8% 6% 5% 6% 4 6% 8% 43%	2000
	21st to end	Day	8% 6% 2 7% 5% 5% 5% 4 6% 8% 44%	1915
December	1st to 10th	Day	5% 3 1 5% 4 4 4 3 6% 8% 57%	2930
	11th to 20th	Day	10% 7% 2 7% 4 4 6% 5% 7% 8% 39%	3373
	21st to end	Day	10% 6% 3 9% 6% 5% 5% 4 6% 8% 37%	4466
January	1st to 10th	Night	8% 5% 2 5% 3 3 4 3 5% 7% 54%	5889
	11th to 20th	Night	19% 9% 3 8% 5% 4 5% 4 6% 7% 30%	5900
	21st to end	Night	15% 6% 2 6% 4 4 4 3 6% 8% 42%	6380
February	1st to 10th	Night	11% 7% 2 5% 4 4 4 4 7% 7% 46%	2400
	11th to 20th	Night	11% 5% 2 5% 4 4 4 4 5% 7% 49%	2338
	21st to end	Night	7% 6% 2 6% 4 3 3 3 5% 8% 53%	1848
March	1st to 10th	Night	11% 7% 3 7% 4 3 4 3 5% 7% 45%	4918
	11th to 20th	Night	6% 3 1 4 3 3 3 3 7% 10% 57%	4980
	21st to end	Night	8% 5% 2 6% 3 4 4 3 6% 8% 49%	5467
April	1st to 10th	Night	6% 4 2 5% 3 4 4 4 6% 10% 53%	2200
	11th to 20th	Night	6% 5% 2 6% 4 4 4 4 5% 8% 51%	2115
	21st to end	Night	5% 4 2 4 4 4 3 3 6% 9% 56%	2000
May	1st to 10th	Night	4 4 2 6% 4 5% 5% 4 6% 9% 51%	4243
	11th to 20th	Night	8% 5% 2 6% 4 4 4 4 6% 8% 49%	4032
	21st to end	Night	5% 4 1 5% 4 5% 5% 4 7% 10% 50%	4421
June	1st to 10th	Night	10% 7% 3 7% 5% 5% 7% 5% 8% 9% 34%	1800
	11th to 20th	Night	6% 8% 2 8% 6% 6% 7% 6% 9% 11% 32%	1800
	21st to end	Night	7% 8% 3 8% 6% 5% 5% 5% 9% 11% 32%	1800
July	1st to 10th	Night	9% 8% 3 9% 7% 7% 7% 7% 9% 11% 24%	4058
	11th to 20th	Night	5% 5% 2 8% 6% 7% 7% 6% 9% 12% 32%	4057
	21st to end	Night	5% 5% 3 9% 6% 7% 7% 6% 8% 11% 32%	4427
August	1st to 10th	Night	4 5% 3 9% 6% 7% 7% 5% 9% 12% 34%	2861
	11th to 20th	Night	4 5% 3 7% 6% 6% 6% 6% 8% 12% 38%	2903
	21st to end	Night	8% 6% 2 7% 6% 6% 6% 6% 9% 12% 32%	3828
September	1st to 10th	Night	7% 7% 3 9% 7% 5% 7% 6% 8% 10% 31%	2090
	11th to 20th	Night	11% 9% 3 9% 7% 6% 6% 5% 7% 9% 29%	2090
	21st to end	Night	9% 8% 3 8% 5% 6% 6% 5% 7% 9% 36%	2090
October	1st to 10th	Night	10% 7% 3 8% 6% 5% 5% 4 6% 7% 40%	2128
	11th to 20th	Night	6% 5% 2 5% 5% 5% 5% 4 6% 7% 49%	2280
	21st to end	Night	7% 5% 2 6% 4 3 4 4 5% 8% 51%	2508
November	1st to 10th	Night	9% 6% 2 5% 4 4 5% 4 6% 7% 48%	2341
	11th to 20th	Night	9% 7% 2 5% 5% 4 4 3 7% 7% 46%	2400
	21st to end	Night	8% 7% 2 6% 5% 5% 4 3 6% 8% 45%	2480
December	1st to 10th	Night	4 3 1 4 4 4 4 4 5% 8% 58%	4250
	11th to 20th	Night	10% 7% 2 5% 4 4 5% 3 5% 7% 47%	4822
	21st to end	Night	12% 8% 3 8% 5% 5% 5% 3 6% 7% 38%	6490

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	31% 4 8% 17% 27% 13%	4057
	11th to 20th	Day	54% 4 5% 16% 15% 7%	4060
	21st to end	Day	37% 4 6% 28% 18% 7%	4558
February	1st to 10th	Day	39% 6% 9% 16% 21% 10%	2000
	11th to 20th	Day	33% 5% 8% 20% 24% 11%	1958
	21st to end	Day	36% 6% 9% 17% 23% 10%	1780
March	1st to 10th	Day	37% 7% 11% 17% 20% 8%	4935
	11th to 20th	Day	22% 5% 9% 23% 22% 19%	4980
	21st to end	Day	34% 5% 10% 26% 17% 8%	5465
April	1st to 10th	Day	31% 7% 13% 23% 19% 8%	2200
	11th to 20th	Day	35% 8% 10% 17% 21% 9%	2231
	21st to end	Day	28% 6% 12% 22% 23% 9%	2400
May	1st to 10th	Day	29% 7% 21% 25% 14% 4	5711
	11th to 20th	Day	34% 8% 14% 29% 12% 1	5865
	21st to end	Day	31% 7% 17% 29% 14% 1	6447
June	1st to 10th	Day	52% 11% 16% 15% 5%	2600
	11th to 20th	Day	49% 12% 19% 18% 3	2600
	21st to end	Day	51% 13% 20% 13% 3	2600
July	1st to 10th	Day	52% 12% 27% 8% 1	5835
	11th to 20th	Day	43% 11% 34% 12%	5831
	21st to end	Day	42% 12% 24% 21% 1	6240
August	1st to 10th	Day	47% 12% 28% 12% 2	4143
	11th to 20th	Day	41% 14% 22% 15% 8%	3911
	21st to end	Day	51% 12% 22% 13% 2	3828
September	1st to 10th	Day	52% 17% 17% 10% 4	2090
	11th to 20th	Day	54% 12% 19% 11% 3	2090
	21st to end	Day	48% 11% 15% 14% 10% 3	2090
October	1st to 10th	Day	59% 8% 12% 9% 7% 4	3402
	11th to 20th	Day	29% 5% 8% 21% 31% 6%	3140
	21st to end	Day	28% 5% 8% 22% 31% 7%	3428
November	1st to 10th	Day	34% 6% 12% 18% 21% 9%	1957
	11th to 20th	Day	38% 7% 9% 19% 20% 7%	2000
	21st to end	Day	37% 6% 9% 21% 19% 8%	1915
December	1st to 10th	Day	26% 4 15% 28% 18% 9%	2930
	11th to 20th	Day	41% 5% 12% 16% 19% 7%	3370
	21st to end	Day	44% 6% 10% 21% 15% 5%	4466
January	1st to 10th	Night	31% 4 7% 20% 26% 12%	5889
	11th to 20th	Night	52% 6% 8% 16% 14% 4	5900
	21st to end	Night	40% 5% 9% 23% 16% 8%	6380
February	1st to 10th	Night	36% 6% 12% 16% 19% 12%	2400
	11th to 20th	Night	34% 6% 10% 20% 21% 9%	2339
	21st to end	Night	30% 5% 13% 20% 24% 8%	1848
March	1st to 10th	Night	38% 6% 10% 20% 19% 7%	4918
	11th to 20th	Night	22% 6% 15% 23% 16% 18%	4980
	21st to end	Night	32% 5% 12% 25% 21% 5%	5467
April	1st to 10th	Night	27% 6% 18% 25% 16% 8%	2200
	11th to 20th	Night	30% 7% 12% 23% 21% 8%	2115
	21st to end	Night	24% 7% 13% 26% 23% 7%	2000
May	1st to 10th	Night	28% 10% 17% 29% 13% 4	4273
	11th to 20th	Night	31% 7% 19% 29% 12% 1	4033
	21st to end	Night	28% 7% 20% 31% 13% 1	4429
June	1st to 10th	Night	44% 11% 20% 22% 5%	1800
	11th to 20th	Night	43% 13% 22% 21% 2	1800
	21st to end	Night	42% 13% 26% 14% 5%	1800
July	1st to 10th	Night	52% 12% 26% 9% 1	4015
	11th to 20th	Night	41% 14% 35% 9% 1	4006
	21st to end	Night	43% 12% 25% 20% 1	4297
August	1st to 10th	Night	41% 12% 33% 13% 2	2850
	11th to 20th	Night	36% 12% 28% 18% 6%	2930
	21st to end	Night	42% 14% 29% 13% 2	3828
September	1st to 10th	Night	44% 18% 21% 13% 4	2090
	11th to 20th	Night	48% 13% 20% 16% 2	2090
	21st to end	Night	43% 10% 17% 19% 9% 2	2090
October	1st to 10th	Night	56% 8% 13% 12% 7% 3	3544
	11th to 20th	Night	30% 7% 7% 27% 24% 4	3779
	21st to end	Night	30% 5% 9% 20% 30% 6%	4120
November	1st to 10th	Night	34% 7% 12% 20% 19% 9%	2341
	11th to 20th	Night	35% 7% 10% 20% 19% 8%	2400
	21st to end	Night	35% 6% 10% 22% 20% 8%	2480
December	1st to 10th	Night	24% 4 16% 31% 13% 13%	4250
	11th to 20th	Night	37% 5% 12% 21% 15% 10%	4824
	21st to end	Night	43% 7% 12% 21% 12% 5%	6490

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	14% 17% 42% 20% 6% 1	300
	11th to 20th	Day	10% 14% 40% 25% 9% 3	300
	21st to end	Day	15% 21% 41% 17% 5%	330
February	1st to 10th	Day	13% 14% 35% 20% 14% 3	300
	11th to 20th	Day	12% 11% 38% 25% 10% 4	300
	21st to end	Day	10% 12% 33% 29% 16% 1	379
March	1st to 10th	Day	7% 14% 36% 30% 13% 1	500
	11th to 20th	Day	10% 12% 32% 27% 17% 3	500
	21st to end	Day	7% 12% 33% 27% 19% 2	550
April	1st to 10th	Day	7% 12% 33% 30% 14% 4	500
	11th to 20th	Day	8% 10% 30% 29% 18% 6%	492
	21st to end	Day	6% 6% 26% 33% 19% 10%	500
May	1st to 10th	Day	4 7% 22% 34% 22% 10%	503
	11th to 20th	Day	9% 4 19% 31% 23% 13%	527
	21st to end	Day	6% 3 12% 25% 33% 20%	573
June	1st to 10th	Day	14% 4 12% 26% 26% 18%	530
	11th to 20th	Day	7% 3 10% 24% 26% 29%	530
	21st to end	Day	6% 2 7% 16% 31% 37%	530
July	1st to 10th	Day	7% 2 3 14% 31% 43%	525
	11th to 20th	Day	6% 2 4 16% 30% 43%	524
	21st to end	Day	6% 2 5% 19% 26% 42%	576
August	1st to 10th	Day	7% 2 6% 18% 33% 35%	502
	11th to 20th	Day	5% 1 4 15% 28% 47%	479
	21st to end	Day	10% 1 9% 21% 26% 33%	539
September	1st to 10th	Day	9% 2 6% 20% 27% 36%	490
	11th to 20th	Day	12% 2 8% 25% 26% 26%	490
	21st to end	Day	10% 3 10% 24% 29% 24%	490
October	1st to 10th	Day	16% 5% 21% 29% 23% 7%	490
	11th to 20th	Day	7% 8% 21% 31% 26% 7%	490
	21st to end	Day	7% 5% 27% 33% 23% 5%	539
November	1st to 10th	Day	10% 7% 23% 30% 26% 4	495
	11th to 20th	Day	12% 9% 24% 35% 16% 4	500
	21st to end	Day	10% 9% 28% 33% 18% 1	415
December	1st to 10th	Day	4 15% 39% 27% 13% 3	300
	11th to 20th	Day	12% 12% 33% 33% 10% 1	300
	21st to end	Day	8% 16% 32% 33% 9% 2	330
January	1st to 10th	Night	11% 11% 34% 32% 12% 1	800
	11th to 20th	Night	11% 11% 29% 38% 11% 1	800
	21st to end	Night	17% 10% 36% 29% 8%	880
February	1st to 10th	Night	14% 7% 33% 32% 13% 1	800
	11th to 20th	Night	12% 8% 35% 33% 10% 1	783
	21st to end	Night	9% 8% 40% 35% 8%	660
March	1st to 10th	Night	7% 10% 38% 35% 10% 1	800
	11th to 20th	Night	9% 10% 30% 37% 13% 1	800
	21st to end	Night	8% 8% 33% 36% 15%	880
April	1st to 10th	Night	8% 8% 33% 39% 13% 1	800
	11th to 20th	Night	8% 7% 33% 36% 15% 1	791
	21st to end	Night	6% 7% 30% 40% 17% 1	800
May	1st to 10th	Night	5% 4 24% 44% 22% 1	696
	11th to 20th	Night	7% 3 18% 42% 26% 4	591
	21st to end	Night	7% 3 11% 38% 37% 5%	650
June	1st to 10th	Night	11% 2 9% 35% 34% 9%	600
	11th to 20th	Night	7% 4 6% 25% 38% 21%	600
	21st to end	Night	8% 3 5% 22% 44% 19%	600
July	1st to 10th	Night	9% 2 3 17% 45% 24%	585
	11th to 20th	Night	7% 2 2 15% 45% 29%	582
	21st to end	Night	5% 1 4 16% 50% 25%	657
August	1st to 10th	Night	5% 1 4 18% 45% 26%	579
	11th to 20th	Night	4 1 4 16% 47% 28%	614
	21st to end	Night	11% 3 8% 20% 39% 19%	836
September	1st to 10th	Night	9% 3 6% 23% 40% 20%	760
	11th to 20th	Night	13% 3 10% 27% 35% 12%	760
	21st to end	Night	13% 2 8% 30% 38% 10%	760
October	1st to 10th	Night	13% 4 18% 34% 26% 4	760
	11th to 20th	Night	7% 4 19% 35% 31% 4	760
	21st to end	Night	9% 4 20% 38% 26% 2	836
November	1st to 10th	Night	11% 5% 24% 34% 24% 3	780
	11th to 20th	Night	9% 7% 25% 39% 18% 2	800
	21st to end	Night	11% 5% 29% 39% 15% 1	800
December	1st to 10th	Night	7% 5% 29% 36% 20% 2	800
	11th to 20th	Night	13% 7% 26% 37% 17% 2	800
	21st to end	Night	11% 7% 31% 34% 16% 1	880

Page generated at 2025-08-02 01:32:28. Version ac07

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