CFAS Ocala Forest Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the CFAS Ocala Forest Site clear sky chart from 2005-11-06 to 2026-09-14.

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% 7% 10% 39%	148405
	Night	8% 6% 2 7% 5% 5% 5% 4 7% 9% 43%	142687
Transparency	Day	38% 7% 17% 20% 13% 5%	152116
	Night	37% 7% 17% 20% 14% 6%	147048
Seeing	Day	10% 7% 22% 25% 22% 14%	18058
	Night	11% 6% 21% 32% 24% 7%	28076

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% 1 6% 3 3 4 3 4 8% 54%	5258
	11th to 20th	Day	19% 9% 3 8% 5% 4 4 4 4 5% 34%	5280
	21st to end	Day	11% 6% 2 6% 3 4 4 3 5% 7% 49%	5900
February	1st to 10th	Day	12% 7% 2 6% 4 3 5% 4 6% 7% 44%	2100
	11th to 20th	Day	10% 5% 2 5% 4 4 4 3 4 7% 51%	2048
	21st to end	Day	9% 6% 3 6% 4 4 4 4 6% 7% 47%	1832
March	1st to 10th	Day	8% 6% 2 8% 5% 4 5% 4 6% 9% 42%	5045
	11th to 20th	Day	5% 4 1 5% 3 3 3 3 5% 8% 59%	5090
	21st to end	Day	9% 5% 2 6% 4 4 5% 4 6% 9% 47%	5586
April	1st to 10th	Day	8% 4 2 5% 4 5% 5% 4 5% 10% 48%	2310
	11th to 20th	Day	7% 5% 3 6% 6% 5% 6% 5% 6% 7% 45%	2337
	21st to end	Day	5% 4 1 5% 4 4 5% 5% 7% 9% 51%	2520
May	1st to 10th	Day	4 4 2 6% 5% 5% 6% 5% 7% 11% 45%	7572
	11th to 20th	Day	9% 5% 2 6% 5% 4 5% 4 6% 9% 45%	7626
	21st to end	Day	4 4 2 6% 5% 6% 7% 6% 8% 13% 40%	8391
June	1st to 10th	Day	9% 7% 3 9% 8% 7% 8% 6% 8% 10% 26%	2730
	11th to 20th	Day	5% 5% 2 9% 8% 8% 9% 7% 9% 11% 26%	2730
	21st to end	Day	8% 6% 3 8% 8% 7% 7% 7% 9% 11% 27%	2730
July	1st to 10th	Day	5% 6% 3 8% 7% 8% 8% 7% 12% 16% 21%	7680
	11th to 20th	Day	3 4 2 7% 7% 7% 8% 7% 10% 16% 29%	7680
	21st to end	Day	5% 5% 2 7% 6% 7% 7% 6% 10% 14% 32%	8340
August	1st to 10th	Day	7% 7% 4 12% 7% 7% 8% 6% 9% 12% 21%	6014
	11th to 20th	Day	3 4 2 6% 5% 6% 7% 6% 9% 14% 38%	5769
	21st to end	Day	6% 5% 3 9% 8% 8% 8% 6% 10% 14% 23%	5566
September	1st to 10th	Day	7% 7% 3 11% 9% 8% 9% 7% 9% 10% 20%	2310
	11th to 20th	Day	9% 8% 3 11% 7% 7% 7% 6% 8% 10% 23%	2233
	21st to end	Day	10% 7% 3 9% 7% 6% 6% 5% 6% 9% 32%	2200
October	1st to 10th	Day	12% 6% 3 9% 6% 6% 6% 5% 7% 7% 33%	2170
	11th to 20th	Day	7% 4 2 5% 5% 4 4 4 7% 9% 49%	2000
	21st to end	Day	9% 4 1 5% 4 5% 5% 4 5% 8% 49%	2200
November	1st to 10th	Day	8% 5% 3 5% 4 5% 5% 4 6% 8% 47%	2057
	11th to 20th	Day	10% 6% 2 6% 5% 6% 5% 4 5% 7% 45%	2100
	21st to end	Day	10% 6% 3 7% 5% 4 4 4 5% 7% 46%	1953
December	1st to 10th	Day	5% 4 2 5% 3 3 4 4 7% 8% 55%	3020
	11th to 20th	Day	10% 7% 3 6% 5% 5% 6% 5% 6% 8% 38%	3463
	21st to end	Day	11% 7% 3 8% 4 4 4 3 5% 7% 43%	4565
January	1st to 10th	Night	8% 5% 2 5% 3 3 3 3 4 8% 56%	7635
	11th to 20th	Night	17% 9% 3 7% 4 4 4 4 5% 7% 35%	7680
	21st to end	Night	13% 6% 2 6% 4 4 4 3 6% 8% 44%	8263
February	1st to 10th	Night	13% 6% 2 6% 4 3 4 3 6% 7% 47%	2520
	11th to 20th	Night	10% 6% 2 6% 4 5% 4 4 5% 7% 48%	2458
	21st to end	Night	9% 5% 2 5% 4 4 4 3 5% 7% 52%	1971
March	1st to 10th	Night	14% 8% 3 7% 4 3 4 3 5% 6% 44%	5028
	11th to 20th	Night	6% 5% 1 5% 3 4 4 3 6% 9% 54%	5090
	21st to end	Night	9% 5% 2 6% 4 4 4 3 5% 8% 50%	5588
April	1st to 10th	Night	9% 4 2 5% 4 3 5% 4 6% 9% 50%	2310
	11th to 20th	Night	7% 5% 2 5% 4 4 3 3 6% 8% 53%	2232
	21st to end	Night	6% 3 1 4 4 4 5% 4 6% 8% 54%	2100
May	1st to 10th	Night	6% 5% 2 6% 5% 4 5% 4 6% 9% 48%	5322
	11th to 20th	Night	9% 7% 2 6% 4 4 5% 3 6% 10% 44%	5234
	21st to end	Night	4 4 2 6% 5% 5% 5% 5% 8% 11% 46%	5761
June	1st to 10th	Night	10% 6% 3 7% 5% 5% 6% 5% 7% 11% 36%	1890
	11th to 20th	Night	5% 6% 3 8% 7% 7% 7% 7% 8% 12% 31%	1890
	21st to end	Night	6% 7% 3 7% 6% 7% 6% 6% 9% 11% 32%	1890
July	1st to 10th	Night	5% 6% 3 9% 6% 7% 7% 8% 12% 14% 23%	5278
	11th to 20th	Night	3 4 2 8% 7% 7% 9% 7% 10% 13% 32%	5277
	21st to end	Night	4 6% 3 9% 6% 7% 7% 6% 9% 11% 33%	5736
August	1st to 10th	Night	5% 6% 3 9% 7% 8% 8% 5% 8% 11% 28%	4135
	11th to 20th	Night	3 3 2 5% 4 6% 6% 5% 9% 15% 43%	4221
	21st to end	Night	6% 6% 2 8% 6% 6% 7% 6% 11% 13% 28%	5559
September	1st to 10th	Night	9% 7% 3 10% 6% 6% 5% 6% 8% 11% 30%	2310
	11th to 20th	Night	10% 8% 3 9% 6% 6% 6% 6% 7% 11% 29%	2234
	21st to end	Night	10% 7% 2 7% 4 6% 6% 5% 7% 9% 37%	2200
October	1st to 10th	Night	11% 7% 3 7% 5% 5% 5% 4 6% 8% 39%	2227
	11th to 20th	Night	5% 4 2 5% 4 4 4 3 6% 9% 53%	2400
	21st to end	Night	9% 5% 2 5% 3 4 4 3 5% 8% 51%	2640
November	1st to 10th	Night	10% 5% 2 5% 4 3 4 4 6% 8% 49%	2461
	11th to 20th	Night	9% 7% 2 7% 4 4 4 4 5% 7% 47%	2520
	21st to end	Night	9% 7% 2 6% 4 5% 4 4 6% 8% 46%	2662
December	1st to 10th	Night	6% 4 2 6% 4 3 3 3 4 7% 57%	4380
	11th to 20th	Night	10% 7% 2 7% 4 4 4 3 5% 6% 47%	4952
	21st to end	Night	13% 8% 3 7% 5% 4 4 4 5% 7% 40%	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	31% 3 12% 17% 25% 12%	5259
	11th to 20th	Day	53% 3 5% 12% 16% 12%	5280
	21st to end	Day	35% 2 9% 26% 16% 12%	5900
February	1st to 10th	Day	39% 4 9% 15% 22% 12%	2100
	11th to 20th	Day	34% 3 9% 20% 23% 11%	2058
	21st to end	Day	36% 3 9% 18% 23% 10%	1832
March	1st to 10th	Day	39% 3 13% 19% 20% 7%	5045
	11th to 20th	Day	25% 2 10% 22% 24% 17%	5090
	21st to end	Day	34% 3 10% 27% 17% 9%	5586
April	1st to 10th	Day	32% 4 13% 22% 20% 9%	2310
	11th to 20th	Day	37% 5% 9% 18% 23% 8%	2337
	21st to end	Day	28% 4 12% 26% 23% 8%	2520
May	1st to 10th	Day	30% 6% 19% 28% 13% 3	7607
	11th to 20th	Day	36% 4 16% 30% 12% 2	7630
	21st to end	Day	32% 9% 20% 26% 11% 1	8405
June	1st to 10th	Day	51% 8% 16% 17% 7% 1	2730
	11th to 20th	Day	47% 10% 21% 20% 3	2730
	21st to end	Day	48% 9% 23% 17% 4	2730
July	1st to 10th	Day	43% 14% 32% 10% 1	7615
	11th to 20th	Day	38% 13% 36% 13%	7611
	21st to end	Day	37% 12% 29% 21% 1	8156
August	1st to 10th	Day	51% 12% 26% 10% 2	6001
	11th to 20th	Day	31% 13% 32% 21% 3	5808
	21st to end	Day	46% 13% 26% 14% 1	5566
September	1st to 10th	Day	54% 14% 18% 11% 3 1	2310
	11th to 20th	Day	53% 8% 19% 14% 5%	2233
	21st to end	Day	48% 7% 13% 18% 11% 3	2200
October	1st to 10th	Day	57% 6% 11% 13% 7% 5%	3534
	11th to 20th	Day	27% 4 8% 21% 31% 9%	3240
	21st to end	Day	27% 4 7% 23% 31% 7%	3538
November	1st to 10th	Day	35% 4 9% 21% 19% 11%	2057
	11th to 20th	Day	39% 4 8% 18% 22% 10%	2100
	21st to end	Day	37% 4 8% 23% 21% 7%	1953
December	1st to 10th	Day	26% 4 16% 26% 20% 9%	3020
	11th to 20th	Day	42% 5% 10% 17% 17% 9%	3460
	21st to end	Day	40% 4 9% 22% 19% 5%	4565
January	1st to 10th	Night	28% 2 11% 21% 26% 11%	7636
	11th to 20th	Night	49% 3 7% 17% 16% 9%	7680
	21st to end	Night	39% 3 12% 21% 15% 10%	8263
February	1st to 10th	Night	37% 3 9% 17% 20% 13%	2520
	11th to 20th	Night	36% 4 11% 21% 19% 10%	2459
	21st to end	Night	32% 4 12% 19% 23% 10%	1971
March	1st to 10th	Night	42% 3 11% 17% 19% 9%	5028
	11th to 20th	Night	28% 3 13% 22% 17% 16%	5090
	21st to end	Night	34% 3 11% 25% 20% 8%	5588
April	1st to 10th	Night	30% 5% 17% 24% 15% 9%	2310
	11th to 20th	Night	30% 4 10% 26% 21% 9%	2232
	21st to end	Night	27% 4 14% 28% 21% 7%	2100
May	1st to 10th	Night	32% 6% 20% 27% 12% 2	5349
	11th to 20th	Night	36% 4 20% 27% 12% 1	5235
	21st to end	Night	30% 9% 21% 26% 13% 1	5771
June	1st to 10th	Night	41% 7% 23% 22% 6%	1890
	11th to 20th	Night	43% 10% 25% 19% 3	1890
	21st to end	Night	43% 10% 24% 17% 5% 1	1890
July	1st to 10th	Night	43% 16% 32% 8% 1	5235
	11th to 20th	Night	38% 16% 34% 11% 1	5226
	21st to end	Night	40% 12% 26% 20% 1	5606
August	1st to 10th	Night	47% 13% 31% 9% 1	4124
	11th to 20th	Night	27% 12% 38% 20% 4	4248
	21st to end	Night	42% 17% 26% 13% 2	5559
September	1st to 10th	Night	47% 13% 21% 14% 5%	2310
	11th to 20th	Night	48% 10% 22% 16% 4	2234
	21st to end	Night	42% 7% 18% 22% 9% 2	2200
October	1st to 10th	Night	54% 8% 12% 15% 7% 5%	3643
	11th to 20th	Night	26% 4 8% 21% 34% 6%	3899
	21st to end	Night	29% 4 9% 21% 30% 7%	4252
November	1st to 10th	Night	33% 5% 11% 22% 19% 11%	2461
	11th to 20th	Night	37% 4 8% 20% 20% 10%	2520
	21st to end	Night	36% 4 10% 23% 20% 8%	2662
December	1st to 10th	Night	29% 3 14% 28% 14% 13%	4380
	11th to 20th	Night	38% 4 11% 22% 16% 9%	4954
	21st to end	Night	44% 4 11% 22% 14% 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	12% 13% 46% 22% 6% 2	330
	11th to 20th	Day	12% 18% 40% 22% 7% 2	330
	21st to end	Day	16% 23% 44% 14% 3	363
February	1st to 10th	Day	18% 14% 34% 24% 10% 1	330
	11th to 20th	Day	14% 12% 46% 19% 8% 2	330
	21st to end	Day	11% 16% 30% 28% 14% 1	375
March	1st to 10th	Day	9% 17% 31% 29% 12% 1	540
	11th to 20th	Day	12% 15% 30% 27% 13% 3	540
	21st to end	Day	10% 12% 29% 29% 16% 3	594
April	1st to 10th	Day	11% 13% 29% 31% 14% 3	540
	11th to 20th	Day	10% 11% 28% 30% 16% 5%	532
	21st to end	Day	6% 7% 25% 31% 19% 11%	540
May	1st to 10th	Day	6% 8% 25% 31% 21% 10%	543
	11th to 20th	Day	9% 4 23% 28% 25% 11%	567
	21st to end	Day	6% 4 14% 26% 35% 16%	617
June	1st to 10th	Day	12% 3 15% 26% 28% 16%	570
	11th to 20th	Day	7% 4 14% 22% 30% 23%	570
	21st to end	Day	6% 2 7% 21% 32% 31%	570
July	1st to 10th	Day	8% 1 5% 16% 31% 39%	565
	11th to 20th	Day	5% 1 5% 20% 31% 38%	564
	21st to end	Day	8% 3 8% 16% 31% 34%	620
August	1st to 10th	Day	8% 3 10% 19% 30% 31%	566
	11th to 20th	Day	5% 1 5% 16% 33% 40%	559
	21st to end	Day	11% 1 8% 19% 32% 28%	627
September	1st to 10th	Day	9% 4 11% 18% 33% 26%	570
	11th to 20th	Day	10% 4 11% 29% 26% 21%	542
	21st to end	Day	11% 4 11% 23% 30% 21%	530
October	1st to 10th	Day	14% 6% 25% 31% 19% 5%	530
	11th to 20th	Day	7% 6% 19% 37% 24% 7%	530
	21st to end	Day	9% 5% 27% 34% 20% 4	583
November	1st to 10th	Day	12% 8% 24% 32% 20% 4	535
	11th to 20th	Day	13% 7% 29% 30% 19% 3	540
	21st to end	Day	11% 10% 36% 28% 12% 3	393
December	1st to 10th	Day	10% 16% 37% 23% 12% 2	330
	11th to 20th	Day	16% 13% 36% 25% 9% 1	330
	21st to end	Day	11% 10% 34% 32% 11% 1	363
January	1st to 10th	Night	13% 11% 34% 29% 12%	840
	11th to 20th	Night	13% 11% 28% 35% 13% 1	840
	21st to end	Night	18% 13% 34% 28% 7%	924
February	1st to 10th	Night	17% 8% 31% 32% 12%	840
	11th to 20th	Night	13% 10% 32% 35% 9% 1	823
	21st to end	Night	13% 9% 35% 37% 7%	692
March	1st to 10th	Night	8% 11% 35% 34% 11%	840
	11th to 20th	Night	10% 11% 33% 31% 13% 1	840
	21st to end	Night	9% 9% 30% 38% 13%	924
April	1st to 10th	Night	10% 8% 32% 37% 13%	840
	11th to 20th	Night	9% 10% 30% 34% 16% 1	831
	21st to end	Night	6% 6% 28% 42% 17% 1	840
May	1st to 10th	Night	6% 3 23% 44% 22% 2	663
	11th to 20th	Night	8% 2 16% 44% 27% 3	621
	21st to end	Night	8% 1 11% 37% 37% 5%	683
June	1st to 10th	Night	11% 2 10% 34% 36% 6%	630
	11th to 20th	Night	7% 3 7% 26% 37% 20%	630
	21st to end	Night	8% 2 5% 23% 43% 19%	630
July	1st to 10th	Night	9% 1 7% 16% 43% 25%	615
	11th to 20th	Night	7% 1 3 15% 47% 26%	612
	21st to end	Night	6% 1 5% 18% 49% 21%	690
August	1st to 10th	Night	8% 2 5% 16% 48% 21%	627
	11th to 20th	Night	6% 1 5% 15% 47% 27%	640
	21st to end	Night	12% 3 8% 21% 37% 19%	924
September	1st to 10th	Night	12% 2 8% 23% 38% 18%	840
	11th to 20th	Night	13% 3 9% 28% 35% 12%	813
	21st to end	Night	14% 2 10% 27% 37% 11%	800
October	1st to 10th	Night	15% 4 17% 37% 24% 4	800
	11th to 20th	Night	6% 4 17% 38% 31% 4	800
	21st to end	Night	11% 5% 19% 37% 25% 3	880
November	1st to 10th	Night	12% 4 23% 35% 24% 2	820
	11th to 20th	Night	13% 6% 24% 36% 19% 2	840
	21st to end	Night	10% 6% 30% 36% 17% 1	840
December	1st to 10th	Night	11% 7% 26% 34% 20% 1	840
	11th to 20th	Night	12% 8% 27% 35% 17% 1	840
	21st to end	Night	14% 8% 27% 35% 16%	924

Page generated at 2026-09-11 04:11:54. Version ac07

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