Fort Boggy State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fort Boggy State Park clear sky chart from 2005-11-06 to 2025-09-19.

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	13% 6% 2 5% 4 4 4 4 5% 8% 46%	126261
	Night	13% 6% 2 5% 3 3 3 3 5% 7% 50%	123030
Transparency	Day	36% 4 11% 22% 19% 8%	129939
	Night	34% 4 10% 21% 20% 11%	127415
Seeing	Day	13% 7% 19% 26% 25% 10%	16185
	Night	14% 7% 25% 34% 18% 2	25962

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	16% 8% 3 5% 3 2 3 3 4 6% 47%	4077
	11th to 20th	Day	14% 5% 2 4 3 2 2 2 4 8% 53%	4080
	21st to end	Day	27% 9% 2 6% 3 2 2 2 2 4 41%	4488
February	1st to 10th	Day	21% 7% 3 6% 3 3 3 2 4 5% 41%	1905
	11th to 20th	Day	21% 8% 2 6% 4 3 4 2 3 5% 41%	1949
	21st to end	Day	21% 7% 2 5% 3 3 3 2 4 6% 44%	1764
March	1st to 10th	Day	17% 8% 3 7% 4 4 3 3 4 6% 41%	4936
	11th to 20th	Day	14% 6% 2 5% 3 3 4 3 4 7% 49%	4980
	21st to end	Day	18% 7% 2 6% 4 4 4 3 5% 6% 41%	5462
April	1st to 10th	Day	15% 8% 3 6% 4 5% 3 3 6% 6% 40%	2200
	11th to 20th	Day	15% 7% 2 6% 5% 5% 5% 4 5% 7% 41%	2309
	21st to end	Day	13% 7% 2 6% 5% 5% 4 3 5% 7% 44%	2400
May	1st to 10th	Day	20% 7% 3 7% 4 4 4 3 6% 8% 35%	5813
	11th to 20th	Day	11% 6% 2 7% 5% 4 5% 4 6% 7% 42%	5862
	21st to end	Day	11% 7% 2 7% 5% 5% 6% 5% 7% 9% 35%	6434
June	1st to 10th	Day	6% 4 2 6% 5% 5% 6% 5% 7% 10% 45%	2600
	11th to 20th	Day	6% 4 2 4 5% 5% 5% 4 7% 11% 48%	2600
	21st to end	Day	5% 5% 2 5% 6% 5% 6% 6% 8% 10% 42%	2600
July	1st to 10th	Day	9% 6% 2 6% 5% 5% 5% 5% 7% 12% 39%	5900
	11th to 20th	Day	4 4 2 5% 4 5% 4 5% 7% 12% 47%	5900
	21st to end	Day	9% 5% 2 6% 5% 5% 5% 5% 6% 9% 42%	6422
August	1st to 10th	Day	2 1 2 2 2 3 3 5% 8% 71%	4234
	11th to 20th	Day	3 2 1 3 3 3 3 4 7% 12% 59%	4124
	21st to end	Day	5% 3 1 5% 5% 5% 5% 5% 8% 11% 46%	4162
September	1st to 10th	Day	8% 5% 2 6% 5% 5% 5% 4 6% 8% 48%	2200
	11th to 20th	Day	11% 5% 2 5% 4 5% 5% 3 7% 8% 45%	2178
	21st to end	Day	6% 4 1 5% 3 4 4 4 6% 8% 53%	2090
October	1st to 10th	Day	7% 3 1 4 3 3 4 3 4 6% 61%	2002
	11th to 20th	Day	13% 4 1 4 2 3 4 3 4 5% 57%	1900
	21st to end	Day	15% 4 1 4 2 2 2 2 3 5% 59%	2090
November	1st to 10th	Day	13% 6% 2 5% 4 4 4 3 4 6% 50%	1958
	11th to 20th	Day	11% 7% 2 5% 3 3 3 3 4 6% 54%	2000
	21st to end	Day	17% 6% 2 7% 4 4 3 2 5% 5% 45%	1823
December	1st to 10th	Day	20% 6% 2 5% 4 3 3 3 4 5% 47%	2940
	11th to 20th	Day	20% 7% 2 5% 4 3 4 3 4 6% 41%	3391
	21st to end	Day	15% 8% 3 6% 4 3 4 3 4 5% 46%	4488
January	1st to 10th	Night	17% 6% 2 5% 3 3 3 2 3 4 54%	5888
	11th to 20th	Night	14% 5% 2 3 2 2 2 2 4 5% 59%	5900
	21st to end	Night	27% 8% 2 5% 3 3 2 2 3 5% 40%	6490
February	1st to 10th	Night	19% 7% 2 6% 4 3 3 2 3 4 46%	2513
	11th to 20th	Night	21% 8% 2 5% 3 3 3 2 4 4 45%	2338
	21st to end	Night	22% 6% 2 4 3 3 2 2 4 5% 47%	1865
March	1st to 10th	Night	19% 8% 2 7% 4 3 3 3 5% 6% 41%	4919
	11th to 20th	Night	14% 6% 2 5% 3 3 3 3 5% 6% 49%	4980
	21st to end	Night	17% 9% 2 6% 4 3 3 2 4 5% 44%	5467
April	1st to 10th	Night	13% 6% 2 5% 4 4 3 3 5% 7% 48%	2200
	11th to 20th	Night	13% 5% 2 5% 3 3 4 4 5% 8% 47%	2040
	21st to end	Night	14% 5% 2 5% 4 3 3 3 5% 7% 49%	2000
May	1st to 10th	Night	17% 10% 3 6% 4 4 4 4 6% 8% 35%	4083
	11th to 20th	Night	10% 6% 2 7% 4 5% 5% 4 6% 7% 43%	4053
	21st to end	Night	10% 6% 2 6% 5% 4 4 4 7% 10% 41%	4443
June	1st to 10th	Night	6% 4 2 4 3 3 3 3 6% 10% 56%	1800
	11th to 20th	Night	4 3 1 2 3 2 3 3 7% 9% 63%	1800
	21st to end	Night	5% 4 2 5% 4 4 4 4 6% 11% 53%	1800
July	1st to 10th	Night	5% 4 2 6% 5% 5% 6% 5% 8% 12% 42%	4078
	11th to 20th	Night	3 3 1 4 3 3 4 4 6% 12% 57%	4077
	21st to end	Night	7% 6% 2 5% 4 4 4 4 7% 10% 48%	4449
August	1st to 10th	Night	1 1 1 1 1 2 2 2 4 9% 76%	2926
	11th to 20th	Night	3 2 1 3 3 4 3 3 6% 13% 60%	2920
	21st to end	Night	4 3 1 4 4 4 5% 5% 7% 11% 52%	3718
September	1st to 10th	Night	7% 4 1 5% 4 4 4 4 6% 8% 52%	2200
	11th to 20th	Night	9% 5% 3 6% 4 4 4 3 6% 7% 50%	2178
	21st to end	Night	7% 3 1 4 3 3 3 3 5% 8% 60%	2090
October	1st to 10th	Night	6% 3 1 3 2 3 3 2 4 7% 67%	2157
	11th to 20th	Night	12% 4 1 4 3 2 3 2 3 5% 61%	2280
	21st to end	Night	13% 4 2 4 3 2 3 2 3 4 61%	2508
November	1st to 10th	Night	12% 5% 2 5% 3 3 3 2 4 6% 55%	2340
	11th to 20th	Night	10% 6% 2 5% 3 3 4 3 5% 6% 54%	2400
	21st to end	Night	17% 6% 2 5% 3 3 3 3 5% 5% 49%	2574
December	1st to 10th	Night	19% 7% 2 6% 3 3 3 3 4 5% 45%	4250
	11th to 20th	Night	17% 10% 3 6% 3 3 3 3 3 4 45%	4816
	21st to end	Night	15% 6% 2 5% 3 3 2 2 3 4 54%	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	39% 3 4 26% 23% 5%	4078
	11th to 20th	Day	34% 2 3 21% 28% 12%	4080
	21st to end	Day	51% 1 3 12% 18% 14%	4488
February	1st to 10th	Day	46% 3 5% 15% 21% 10%	1905
	11th to 20th	Day	48% 3 6% 16% 18% 9%	1959
	21st to end	Day	44% 2 7% 17% 18% 13%	1764
March	1st to 10th	Day	46% 3 6% 13% 21% 12%	4936
	11th to 20th	Day	38% 2 7% 13% 19% 22%	4980
	21st to end	Day	45% 3 8% 21% 18% 6%	5464
April	1st to 10th	Day	45% 4 8% 19% 14% 10%	2200
	11th to 20th	Day	43% 4 9% 16% 18% 9%	2309
	21st to end	Day	41% 4 8% 20% 22% 6%	2400
May	1st to 10th	Day	48% 3 11% 23% 12% 3	5851
	11th to 20th	Day	41% 4 12% 17% 24% 2	5866
	21st to end	Day	43% 5% 13% 23% 15% 2	6447
June	1st to 10th	Day	33% 5% 15% 31% 15% 2	2600
	11th to 20th	Day	28% 6% 14% 31% 17% 4	2600
	21st to end	Day	34% 8% 14% 26% 16% 2	2600
July	1st to 10th	Day	36% 8% 26% 25% 5%	5836
	11th to 20th	Day	28% 7% 20% 31% 13%	5831
	21st to end	Day	37% 6% 15% 29% 12% 1	6240
August	1st to 10th	Day	13% 4 14% 41% 28% 1	4220
	11th to 20th	Day	18% 4 27% 40% 10% 1	4163
	21st to end	Day	30% 11% 19% 26% 13% 2	4161
September	1st to 10th	Day	34% 6% 12% 22% 17% 9%	2200
	11th to 20th	Day	36% 5% 15% 21% 16% 7%	2178
	21st to end	Day	28% 6% 10% 23% 19% 14%	2090
October	1st to 10th	Day	16% 3 6% 13% 22% 41%	3327
	11th to 20th	Day	19% 2 4 20% 34% 21%	3140
	21st to end	Day	26% 2 4 21% 35% 13%	3428
November	1st to 10th	Day	36% 4 8% 19% 22% 10%	1958
	11th to 20th	Day	34% 3 8% 19% 23% 14%	2000
	21st to end	Day	43% 3 6% 18% 19% 10%	1823
December	1st to 10th	Day	41% 2 8% 18% 23% 7%	2940
	11th to 20th	Day	44% 4 6% 13% 23% 10%	3389
	21st to end	Day	42% 2 4 15% 28% 8%	4488
January	1st to 10th	Night	37% 3 4 23% 26% 8%	5888
	11th to 20th	Night	30% 1 4 18% 33% 13%	5900
	21st to end	Night	51% 1 3 13% 17% 15%	6490
February	1st to 10th	Night	44% 3 4 13% 20% 16%	2513
	11th to 20th	Night	44% 3 5% 16% 19% 13%	2338
	21st to end	Night	42% 3 7% 14% 18% 16%	1865
March	1st to 10th	Night	45% 3 5% 13% 21% 13%	4919
	11th to 20th	Night	38% 3 6% 16% 15% 22%	4980
	21st to end	Night	44% 3 8% 17% 20% 9%	5467
April	1st to 10th	Night	37% 5% 9% 19% 18% 12%	2200
	11th to 20th	Night	35% 4 11% 20% 17% 13%	2040
	21st to end	Night	35% 4 10% 19% 25% 7%	2000
May	1st to 10th	Night	48% 4 10% 23% 12% 3	4110
	11th to 20th	Night	40% 5% 12% 19% 22% 2	4054
	21st to end	Night	38% 5% 15% 28% 12% 3	4452
June	1st to 10th	Night	25% 6% 18% 31% 19% 2	1800
	11th to 20th	Night	18% 5% 18% 34% 20% 6%	1800
	21st to end	Night	27% 7% 16% 30% 18% 3	1800
July	1st to 10th	Night	33% 8% 28% 27% 4	4035
	11th to 20th	Night	20% 6% 24% 37% 12%	4026
	21st to end	Night	31% 7% 20% 29% 12% 1	4320
August	1st to 10th	Night	8% 4 14% 37% 34% 3	2916
	11th to 20th	Night	19% 5% 23% 41% 10% 2	2947
	21st to end	Night	26% 8% 21% 29% 13% 2	3718
September	1st to 10th	Night	30% 5% 16% 22% 17% 10%	2200
	11th to 20th	Night	33% 7% 15% 21% 17% 7%	2178
	21st to end	Night	24% 5% 11% 23% 23% 14%	2090
October	1st to 10th	Night	12% 3 6% 16% 19% 44%	3599
	11th to 20th	Night	17% 1 3 20% 33% 26%	3779
	21st to end	Night	23% 2 4 20% 34% 17%	4120
November	1st to 10th	Night	32% 4 9% 20% 22% 13%	2340
	11th to 20th	Night	32% 3 7% 20% 23% 15%	2400
	21st to end	Night	39% 3 8% 16% 21% 12%	2574
December	1st to 10th	Night	44% 2 5% 18% 23% 8%	4250
	11th to 20th	Night	44% 3 7% 10% 23% 13%	4817
	21st to end	Night	36% 2 5% 16% 30% 12%	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	24% 15% 31% 22% 6% 2	300
	11th to 20th	Day	22% 14% 35% 20% 8% 1	300
	21st to end	Day	24% 14% 36% 18% 8%	330
February	1st to 10th	Day	26% 14% 35% 21% 5%	300
	11th to 20th	Day	28% 20% 31% 17% 4	300
	21st to end	Day	29% 17% 37% 13% 4	249
March	1st to 10th	Day	24% 17% 29% 21% 8%	300
	11th to 20th	Day	18% 18% 38% 20% 5%	300
	21st to end	Day	19% 11% 39% 21% 8% 2	330
April	1st to 10th	Day	23% 13% 37% 21% 5% 1	300
	11th to 20th	Day	22% 15% 30% 21% 12% 1	427
	21st to end	Day	17% 10% 32% 29% 11% 2	500
May	1st to 10th	Day	17% 10% 31% 31% 10% 1	680
	11th to 20th	Day	15% 7% 25% 32% 16% 5%	725
	21st to end	Day	12% 6% 23% 33% 21% 5%	789
June	1st to 10th	Day	7% 2 12% 37% 31% 11%	730
	11th to 20th	Day	6% 2 13% 38% 32% 9%	730
	21st to end	Day	7% 3 10% 28% 37% 16%	730
July	1st to 10th	Day	8% 2 7% 27% 37% 18%	721
	11th to 20th	Day	4 1 5% 28% 44% 19%	718
	21st to end	Day	6% 1 4 21% 48% 19%	794
August	1st to 10th	Day	5% 1 2 20% 51% 21%	726
	11th to 20th	Day	6% 1 2 23% 47% 21%	694
	21st to end	Day	8% 1 4 18% 37% 31%	498
September	1st to 10th	Day	5% 7% 24% 36% 27%	330
	11th to 20th	Day	7% 2 6% 20% 39% 26%	324
	21st to end	Day	10% 2 9% 22% 37% 21%	300
October	1st to 10th	Day	5% 1 15% 30% 38% 10%	300
	11th to 20th	Day	10% 5% 22% 37% 20% 7%	300
	21st to end	Day	19% 14% 22% 22% 18% 5%	330
November	1st to 10th	Day	19% 5% 21% 31% 19% 6%	300
	11th to 20th	Day	18% 6% 28% 32% 14% 3	300
	21st to end	Day	19% 14% 30% 22% 13% 2	300
December	1st to 10th	Day	20% 7% 32% 25% 11% 6%	300
	11th to 20th	Day	27% 13% 30% 22% 7% 1	300
	21st to end	Day	20% 12% 36% 25% 7% 1	330
January	1st to 10th	Night	20% 10% 34% 29% 7%	1000
	11th to 20th	Night	22% 13% 30% 27% 8%	1000
	21st to end	Night	22% 10% 33% 29% 6%	1100
February	1st to 10th	Night	24% 12% 32% 28% 4	913
	11th to 20th	Night	27% 11% 36% 23% 4	784
	21st to end	Night	26% 13% 38% 22% 2	545
March	1st to 10th	Night	23% 11% 35% 26% 5%	600
	11th to 20th	Night	16% 12% 39% 26% 7%	600
	21st to end	Night	14% 12% 42% 26% 5%	660
April	1st to 10th	Night	13% 11% 43% 26% 7%	600
	11th to 20th	Night	13% 12% 36% 30% 8% 1	593
	21st to end	Night	16% 9% 38% 27% 10% 1	600
May	1st to 10th	Night	12% 10% 37% 33% 7% 1	600
	11th to 20th	Night	15% 6% 28% 36% 15% 1	591
	21st to end	Night	8% 3 26% 43% 19% 2	650
June	1st to 10th	Night	7% 2 13% 43% 31% 3	600
	11th to 20th	Night	5% 1 18% 51% 23% 3	600
	21st to end	Night	5% 1 9% 44% 35% 7%	600
July	1st to 10th	Night	5% 2 7% 44% 36% 6%	585
	11th to 20th	Night	2 1 4 50% 37% 5%	582
	21st to end	Night	4 3 6% 42% 41% 5%	657
August	1st to 10th	Night	3 1 4 45% 43% 4	597
	11th to 20th	Night	5% 1 5% 41% 42% 7%	594
	21st to end	Night	5% 1 6% 35% 45% 8%	660
September	1st to 10th	Night	8% 1 6% 39% 42% 5%	600
	11th to 20th	Night	10% 1 7% 33% 44% 5%	594
	21st to end	Night	9% 1 9% 35% 40% 5%	570
October	1st to 10th	Night	6% 1 12% 45% 32% 5%	637
	11th to 20th	Night	13% 4 20% 41% 19% 2	760
	21st to end	Night	13% 8% 26% 32% 19% 2	836
November	1st to 10th	Night	13% 4 25% 35% 21% 1	780
	11th to 20th	Night	12% 9% 27% 39% 14%	800
	21st to end	Night	18% 10% 28% 28% 14% 1	974
December	1st to 10th	Night	20% 7% 30% 31% 11%	1000
	11th to 20th	Night	24% 10% 29% 31% 7%	1000
	21st to end	Night	21% 8% 31% 32% 8%	1100

Page generated at 2025-09-16 00:49:12. Version ac07

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