Fox Run Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fox Run Park clear sky chart from 2005-11-06 to 2025-10-19.

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 6% 5% 5% 5% 4 6% 8% 40%	126423
	Night	15% 7% 2 5% 4 3 4 3 5% 7% 45%	123537
Transparency	Day	39% 6% 11% 19% 16% 7%	130072
	Night	37% 5% 11% 20% 17% 9%	127951
Seeing	Day	15% 8% 21% 26% 22% 8%	16150
	Night	16% 7% 23% 32% 19% 2	25935

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	20% 10% 3 6% 3 3 3 3 3 4 42%	4077
	11th to 20th	Day	16% 6% 2 5% 4 3 3 2 3 5% 50%	4080
	21st to end	Day	31% 8% 2 5% 3 2 2 2 4 6% 35%	4488
February	1st to 10th	Day	22% 7% 3 7% 4 4 3 3 3 5% 38%	1886
	11th to 20th	Day	22% 8% 4 7% 4 3 4 2 4 4 39%	1964
	21st to end	Day	20% 9% 2 6% 4 4 3 2 4 6% 39%	1815
March	1st to 10th	Day	16% 8% 3 7% 5% 5% 4 4 5% 7% 37%	4936
	11th to 20th	Day	15% 6% 2 5% 4 4 3 3 5% 5% 46%	4980
	21st to end	Day	18% 7% 3 6% 4 4 4 3 5% 5% 39%	5462
April	1st to 10th	Day	15% 10% 3 8% 5% 4 4 4 5% 5% 38%	2200
	11th to 20th	Day	18% 6% 2 6% 5% 4 4 4 5% 7% 39%	2333
	21st to end	Day	11% 7% 3 7% 5% 5% 5% 3 5% 6% 41%	2400
May	1st to 10th	Day	18% 8% 2 8% 5% 5% 5% 4 6% 7% 31%	5538
	11th to 20th	Day	11% 6% 2 7% 4 5% 5% 4 6% 8% 43%	5862
	21st to end	Day	10% 7% 3 7% 5% 6% 5% 5% 8% 10% 35%	6434
June	1st to 10th	Day	6% 5% 2 7% 6% 5% 7% 5% 7% 9% 42%	2600
	11th to 20th	Day	6% 4 1 6% 6% 7% 6% 6% 8% 11% 39%	2600
	21st to end	Day	6% 6% 3 7% 8% 8% 9% 5% 9% 10% 29%	2600
July	1st to 10th	Day	9% 5% 2 7% 7% 7% 7% 6% 8% 11% 32%	5900
	11th to 20th	Day	6% 5% 2 7% 6% 6% 7% 7% 9% 12% 31%	5900
	21st to end	Day	11% 7% 3 7% 5% 5% 5% 5% 7% 10% 35%	6422
August	1st to 10th	Day	2 2 1 3 4 4 6% 4 6% 10% 58%	4234
	11th to 20th	Day	3 2 1 4 5% 6% 7% 6% 9% 12% 45%	4012
	21st to end	Day	8% 4 2 8% 6% 6% 7% 5% 7% 10% 37%	4247
September	1st to 10th	Day	7% 5% 2 6% 6% 6% 6% 5% 8% 10% 39%	2200
	11th to 20th	Day	12% 7% 3 8% 5% 5% 6% 4 6% 8% 38%	2200
	21st to end	Day	7% 5% 2 7% 4 5% 5% 4 6% 8% 48%	2200
October	1st to 10th	Day	7% 3 1 5% 3 4 4 3 5% 6% 59%	2076
	11th to 20th	Day	9% 5% 3 5% 5% 4 4 3 5% 6% 52%	1980
	21st to end	Day	13% 5% 2 5% 4 3 3 3 4 6% 53%	2090
November	1st to 10th	Day	11% 6% 2 7% 5% 4 4 3 5% 7% 46%	1958
	11th to 20th	Day	12% 6% 2 6% 4 4 4 3 5% 6% 48%	2000
	21st to end	Day	16% 7% 2 6% 5% 4 4 2 4 6% 43%	1930
December	1st to 10th	Day	23% 8% 2 6% 4 3 3 2 5% 6% 38%	2940
	11th to 20th	Day	15% 7% 2 6% 4 4 4 3 5% 7% 42%	3391
	21st to end	Day	17% 7% 2 6% 3 4 4 2 4 5% 47%	4488
January	1st to 10th	Night	19% 7% 2 5% 3 3 3 3 4 5% 46%	5888
	11th to 20th	Night	17% 6% 2 4 3 3 3 2 3 5% 51%	5900
	21st to end	Night	30% 8% 2 5% 3 2 3 3 3 5% 35%	6490
February	1st to 10th	Night	22% 8% 3 7% 3 3 3 2 4 6% 40%	2530
	11th to 20th	Night	22% 8% 3 5% 4 3 3 2 3 5% 42%	2320
	21st to end	Night	22% 8% 3 5% 4 3 4 3 4 5% 39%	1815
March	1st to 10th	Night	22% 9% 3 6% 3 3 3 3 4 6% 37%	4919
	11th to 20th	Night	18% 7% 2 6% 4 3 3 3 4 5% 45%	4980
	21st to end	Night	21% 9% 3 6% 4 3 3 2 3 5% 41%	5467
April	1st to 10th	Night	16% 7% 3 6% 4 4 5% 3 5% 7% 40%	2200
	11th to 20th	Night	18% 6% 2 6% 3 2 4 3 5% 7% 44%	2015
	21st to end	Night	16% 6% 2 5% 4 4 4 3 5% 6% 45%	2000
May	1st to 10th	Night	23% 11% 3 7% 5% 4 4 3 6% 7% 29%	4358
	11th to 20th	Night	13% 7% 2 6% 4 4 5% 4 6% 8% 41%	4053
	21st to end	Night	14% 8% 3 7% 5% 4 5% 5% 7% 9% 32%	4443
June	1st to 10th	Night	5% 4 2 5% 3 3 3 4 6% 10% 55%	1800
	11th to 20th	Night	4 3 1 3 3 3 5% 4 7% 11% 56%	1800
	21st to end	Night	5% 5% 2 5% 5% 5% 5% 5% 8% 12% 44%	1800
July	1st to 10th	Night	6% 5% 2 6% 5% 4 5% 5% 9% 13% 41%	4078
	11th to 20th	Night	4 4 2 5% 4 4 6% 4 6% 12% 48%	4077
	21st to end	Night	8% 6% 3 5% 4 4 5% 4 6% 9% 47%	4449
August	1st to 10th	Night	1 1 1 3 3 2 3 2 6% 9% 68%	2926
	11th to 20th	Night	2 2 1 2 2 3 3 4 7% 13% 61%	3038
	21st to end	Night	5% 3 1 5% 4 6% 6% 5% 8% 11% 46%	3644
September	1st to 10th	Night	5% 5% 1 7% 4 4 6% 3 7% 9% 47%	2200
	11th to 20th	Night	11% 6% 2 7% 4 4 4 4 6% 8% 45%	2200
	21st to end	Night	7% 4 1 5% 4 4 4 3 6% 7% 56%	2200
October	1st to 10th	Night	4 3 2 4 3 3 3 3 5% 7% 61%	2301
	11th to 20th	Night	10% 4 1 3 2 2 3 2 5% 6% 61%	2377
	21st to end	Night	11% 5% 2 4 3 3 3 2 3 4 59%	2508
November	1st to 10th	Night	12% 6% 2 5% 3 3 4 3 4 6% 52%	2340
	11th to 20th	Night	13% 6% 2 5% 3 3 4 3 5% 6% 51%	2400
	21st to end	Night	17% 6% 2 5% 4 4 3 3 5% 6% 46%	2465
December	1st to 10th	Night	20% 10% 3 8% 4 4 3 3 4 5% 35%	4250
	11th to 20th	Night	16% 10% 3 6% 3 3 3 3 4 5% 45%	4816
	21st to end	Night	16% 7% 2 5% 3 3 3 2 4 5% 49%	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	47% 3 4 21% 18% 7%	4078
	11th to 20th	Day	38% 3 3 18% 25% 12%	4080
	21st to end	Day	53% 2 3 13% 15% 14%	4488
February	1st to 10th	Day	49% 4 5% 13% 17% 12%	1886
	11th to 20th	Day	50% 3 6% 14% 16% 10%	1974
	21st to end	Day	48% 4 7% 15% 15% 11%	1815
March	1st to 10th	Day	47% 6% 7% 13% 17% 11%	4936
	11th to 20th	Day	39% 5% 6% 10% 20% 20%	4980
	21st to end	Day	46% 5% 7% 19% 18% 6%	5464
April	1st to 10th	Day	48% 5% 6% 16% 16% 9%	2200
	11th to 20th	Day	45% 5% 8% 16% 17% 9%	2333
	21st to end	Day	41% 6% 8% 19% 20% 6%	2400
May	1st to 10th	Day	49% 7% 10% 21% 11% 3	5573
	11th to 20th	Day	38% 6% 12% 21% 20% 2	5866
	21st to end	Day	40% 8% 12% 28% 11% 1	6447
June	1st to 10th	Day	36% 9% 15% 23% 16% 1	2600
	11th to 20th	Day	35% 9% 15% 24% 15% 3	2600
	21st to end	Day	45% 9% 16% 21% 8% 1	2600
July	1st to 10th	Day	40% 9% 29% 20% 2	5836
	11th to 20th	Day	39% 10% 25% 21% 6%	5831
	21st to end	Day	41% 9% 18% 24% 8%	6240
August	1st to 10th	Day	19% 7% 16% 38% 20%	4220
	11th to 20th	Day	26% 10% 30% 27% 6% 1	4051
	21st to end	Day	39% 11% 15% 19% 13% 1	4246
September	1st to 10th	Day	37% 10% 15% 19% 14% 6%	2200
	11th to 20th	Day	42% 7% 11% 20% 15% 4	2200
	21st to end	Day	33% 6% 12% 19% 17% 12%	2200
October	1st to 10th	Day	18% 3 6% 15% 20% 39%	3375
	11th to 20th	Day	23% 4 5% 17% 33% 19%	3220
	21st to end	Day	27% 4 5% 15% 35% 13%	3428
November	1st to 10th	Day	37% 5% 10% 18% 20% 10%	1958
	11th to 20th	Day	38% 4 9% 14% 22% 14%	2000
	21st to end	Day	44% 4 7% 17% 18% 11%	1930
December	1st to 10th	Day	48% 4 6% 17% 21% 5%	2940
	11th to 20th	Day	41% 5% 8% 15% 21% 11%	3389
	21st to end	Day	40% 5% 5% 15% 26% 10%	4488
January	1st to 10th	Night	40% 4 6% 22% 19% 8%	5888
	11th to 20th	Night	37% 2 4 19% 26% 11%	5900
	21st to end	Night	53% 3 4 13% 16% 12%	6490
February	1st to 10th	Night	47% 4 6% 13% 16% 14%	2530
	11th to 20th	Night	46% 3 6% 15% 18% 11%	2320
	21st to end	Night	48% 4 6% 14% 16% 13%	1815
March	1st to 10th	Night	49% 4 5% 14% 19% 9%	4919
	11th to 20th	Night	41% 5% 6% 13% 16% 17%	4980
	21st to end	Night	47% 5% 7% 15% 19% 8%	5467
April	1st to 10th	Night	43% 6% 9% 17% 16% 10%	2200
	11th to 20th	Night	40% 6% 9% 17% 16% 12%	2015
	21st to end	Night	40% 5% 10% 21% 19% 6%	2000
May	1st to 10th	Night	54% 6% 9% 20% 8% 3	4388
	11th to 20th	Night	38% 7% 13% 20% 19% 3	4054
	21st to end	Night	45% 8% 15% 24% 7% 1	4452
June	1st to 10th	Night	23% 7% 18% 33% 18%	1800
	11th to 20th	Night	21% 8% 20% 30% 18% 4	1800
	21st to end	Night	30% 9% 22% 27% 12% 1	1800
July	1st to 10th	Night	32% 9% 34% 22% 3	4035
	11th to 20th	Night	28% 8% 29% 29% 6%	4026
	21st to end	Night	34% 9% 20% 29% 8%	4320
August	1st to 10th	Night	11% 6% 19% 45% 18% 1	2916
	11th to 20th	Night	14% 7% 36% 35% 7% 1	3065
	21st to end	Night	30% 13% 21% 26% 9% 1	3644
September	1st to 10th	Night	31% 9% 21% 20% 13% 6%	2200
	11th to 20th	Night	35% 7% 15% 22% 15% 5%	2200
	21st to end	Night	27% 6% 14% 24% 17% 12%	2200
October	1st to 10th	Night	16% 4 7% 18% 17% 38%	3769
	11th to 20th	Night	15% 3 5% 24% 32% 21%	3876
	21st to end	Night	23% 3 5% 16% 37% 16%	4120
November	1st to 10th	Night	33% 5% 11% 20% 20% 10%	2340
	11th to 20th	Night	34% 4 9% 19% 21% 13%	2400
	21st to end	Night	40% 4 8% 18% 19% 11%	2465
December	1st to 10th	Night	51% 3 5% 16% 18% 6%	4250
	11th to 20th	Night	44% 3 9% 9% 21% 13%	4817
	21st to end	Night	38% 4 6% 14% 30% 9%	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	28% 15% 36% 18% 3 1	300
	11th to 20th	Day	31% 11% 32% 21% 4 1	300
	21st to end	Day	30% 16% 36% 13% 5%	330
February	1st to 10th	Day	29% 18% 27% 20% 6%	300
	11th to 20th	Day	31% 17% 34% 15% 2	300
	21st to end	Day	27% 21% 36% 12% 4	249
March	1st to 10th	Day	27% 18% 36% 16% 3	300
	11th to 20th	Day	22% 24% 38% 12% 3 1	300
	21st to end	Day	26% 15% 40% 14% 5%	330
April	1st to 10th	Day	21% 22% 38% 16% 4	300
	11th to 20th	Day	27% 14% 27% 21% 10%	451
	21st to end	Day	17% 14% 37% 22% 9% 1	500
May	1st to 10th	Day	19% 12% 35% 25% 9% 1	558
	11th to 20th	Day	16% 6% 33% 30% 13% 2	725
	21st to end	Day	13% 7% 29% 32% 15% 4	789
June	1st to 10th	Day	9% 2 16% 36% 27% 10%	730
	11th to 20th	Day	7% 3 16% 38% 28% 8%	730
	21st to end	Day	8% 3 10% 33% 30% 15%	730
July	1st to 10th	Day	9% 3 8% 29% 36% 16%	721
	11th to 20th	Day	5% 2 4 29% 42% 19%	718
	21st to end	Day	5% 3 5% 27% 45% 15%	794
August	1st to 10th	Day	4 1 3 25% 50% 18%	726
	11th to 20th	Day	5% 1 2 22% 44% 25%	621
	21st to end	Day	9% 1 6% 23% 35% 26%	544
September	1st to 10th	Day	7% 1 9% 32% 32% 18%	330
	11th to 20th	Day	10% 2 10% 32% 33% 13%	330
	21st to end	Day	10% 3 11% 35% 31% 11%	330
October	1st to 10th	Day	6% 2 18% 45% 25% 4	330
	11th to 20th	Day	9% 4 23% 39% 20% 6%	324
	21st to end	Day	21% 8% 25% 25% 15% 5%	330
November	1st to 10th	Day	18% 6% 24% 37% 13% 2	300
	11th to 20th	Day	18% 8% 32% 32% 9% 1	300
	21st to end	Day	23% 18% 29% 20% 8% 3	300
December	1st to 10th	Day	23% 9% 37% 20% 7% 4	300
	11th to 20th	Day	25% 15% 31% 23% 5% 1	300
	21st to end	Day	25% 11% 36% 21% 6% 1	330
January	1st to 10th	Night	24% 10% 33% 26% 7%	1000
	11th to 20th	Night	24% 13% 28% 29% 6%	1000
	21st to end	Night	24% 12% 30% 29% 6%	1100
February	1st to 10th	Night	27% 12% 30% 27% 4	930
	11th to 20th	Night	29% 10% 30% 25% 4	766
	21st to end	Night	27% 13% 35% 23% 3	495
March	1st to 10th	Night	26% 10% 33% 27% 5%	600
	11th to 20th	Night	22% 9% 36% 27% 6%	600
	21st to end	Night	19% 12% 37% 25% 7%	660
April	1st to 10th	Night	19% 11% 37% 28% 6%	600
	11th to 20th	Night	23% 9% 32% 28% 8%	593
	21st to end	Night	20% 7% 36% 27% 9%	600
May	1st to 10th	Night	19% 10% 32% 32% 7%	600
	11th to 20th	Night	15% 3 32% 34% 14% 1	591
	21st to end	Night	11% 4 29% 37% 18% 2	650
June	1st to 10th	Night	7% 2 14% 46% 29% 3	600
	11th to 20th	Night	4 2 17% 50% 25% 2	600
	21st to end	Night	7% 2 13% 40% 35% 5%	600
July	1st to 10th	Night	5% 3 7% 41% 36% 8%	585
	11th to 20th	Night	5% 1 5% 40% 42% 8%	582
	21st to end	Night	4 1 5% 41% 44% 6%	657
August	1st to 10th	Night	3 3 45% 43% 6%	597
	11th to 20th	Night	4 1 4 39% 47% 6%	594
	21st to end	Night	5% 1 6% 29% 48% 10%	660
September	1st to 10th	Night	7% 2 7% 30% 46% 9%	600
	11th to 20th	Night	13% 1 6% 32% 43% 6%	600
	21st to end	Night	9% 2 9% 36% 40% 4	600
October	1st to 10th	Night	6% 2 13% 39% 35% 5%	701
	11th to 20th	Night	11% 3 23% 38% 23% 1	793
	21st to end	Night	15% 7% 26% 31% 19% 2	836
November	1st to 10th	Night	13% 5% 24% 36% 20% 1	780
	11th to 20th	Night	15% 8% 26% 35% 16%	800
	21st to end	Night	20% 8% 30% 27% 13% 1	865
December	1st to 10th	Night	24% 7% 28% 28% 12% 1	1000
	11th to 20th	Night	25% 10% 27% 31% 7% 1	1000
	21st to end	Night	23% 9% 29% 29% 8%	1100

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