Fox Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fox Park clear sky chart from 2005-11-06 to 2025-12-18.

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	3 5% 3 7% 5% 5% 5% 5% 7% 8% 47%	136145
	Night	2 4 2 6% 4 4 5% 4 7% 9% 53%	132357
Transparency	Day	17% 40% 8% 16% 13% 5%	131038
	Night	14% 41% 10% 18% 14% 4	128468
Seeing	Day	13% 27% 32% 18% 8% 1	17167
	Night	8% 29% 30% 22% 10% 1	27254

By Month

Percentage Cloud Cover SW (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	3 2 9% 7% 5% 7% 5% 9% 10% 43%	3638
	11th to 20th	Day	3 3 10% 10% 9% 6% 5% 7% 8% 39%	3794
	21st to end	Day	4 3 8% 5% 5% 5% 4 7% 8% 51%	4510
February	1st to 10th	Day	4 5% 13% 7% 6% 5% 4 7% 10% 39%	1800
	11th to 20th	Day	4 3 9% 9% 6% 6% 6% 7% 9% 41%	1830
	21st to end	Day	6% 4 9% 9% 7% 6% 4 6% 8% 41%	1650
March	1st to 10th	Day	7% 5% 11% 6% 4 5% 4 5% 7% 46%	4592
	11th to 20th	Day	1 7% 4 7% 5% 5% 5% 4 6% 10% 46%	5000
	21st to end	Day	1 7% 3 8% 6% 6% 7% 5% 9% 10% 38%	5705
April	1st to 10th	Day	3 9% 4 9% 6% 5% 5% 4 6% 8% 42%	2400
	11th to 20th	Day	4 12% 4 9% 6% 5% 5% 4 6% 7% 37%	2371
	21st to end	Day	5% 10% 4 9% 6% 5% 6% 3 7% 8% 37%	2400
May	1st to 10th	Day	6% 16% 4 9% 5% 5% 5% 4 6% 6% 33%	5974
	11th to 20th	Day	5% 7% 2 7% 5% 6% 6% 5% 8% 9% 39%	6298
	21st to end	Day	4 5% 2 7% 5% 6% 6% 5% 8% 9% 42%	6925
June	1st to 10th	Day	4 5% 2 6% 5% 5% 6% 5% 7% 9% 46%	2800
	11th to 20th	Day	5% 4 1 5% 3 4 5% 5% 6% 7% 54%	2800
	21st to end	Day	2 3 2 4 4 5% 6% 5% 6% 8% 55%	2800
July	1st to 10th	Day	3 3 1 5% 4 5% 6% 5% 8% 9% 52%	6339
	11th to 20th	Day	2 2 1 6% 5% 7% 7% 6% 8% 8% 49%	6340
	21st to end	Day	4 4 2 6% 6% 6% 7% 5% 8% 8% 46%	6728
August	1st to 10th	Day	2 3 1 6% 5% 5% 6% 6% 8% 10% 47%	5779
	11th to 20th	Day	3 4 2 7% 5% 5% 6% 5% 6% 8% 50%	5584
	21st to end	Day	5% 5% 2 7% 5% 5% 5% 5% 7% 8% 46%	5984
September	1st to 10th	Day	4 4 2 6% 4 4 4 3 4 6% 59%	2400
	11th to 20th	Day	4 4 2 5% 4 3 4 4 6% 6% 56%	2400
	21st to end	Day	6% 4 2 4 3 3 3 3 5% 5% 62%	2151
October	1st to 10th	Day	3 3 1 4 2 2 3 2 4 5% 70%	3270
	11th to 20th	Day	3 5% 2 6% 3 4 4 4 6% 8% 55%	3250
	21st to end	Day	2 7% 3 6% 3 3 4 3 5% 7% 56%	3470
November	1st to 10th	Day	1 4 2 5% 4 4 5% 4 6% 7% 57%	1853
	11th to 20th	Day	2 5% 3 5% 5% 5% 4 3 6% 9% 55%	1844
	21st to end	Day	1 4 2 8% 6% 4 4 4 6% 9% 52%	1680
December	1st to 10th	Day	2 1 6% 5% 4 4 3 6% 7% 61%	2700
	11th to 20th	Day	2 1 7% 5% 5% 5% 4 5% 9% 55%	3082
	21st to end	Day	1 4 3 10% 5% 5% 5% 5% 9% 10% 42%	4004
January	1st to 10th	Night	3 3 12% 6% 5% 5% 5% 8% 10% 42%	6327
	11th to 20th	Night	1 1 7% 6% 9% 6% 5% 8% 11% 44%	6230
	21st to end	Night	3 2 7% 5% 5% 6% 5% 8% 10% 50%	6468
February	1st to 10th	Night	3 2 7% 6% 5% 6% 6% 8% 11% 45%	2600
	11th to 20th	Night	3 2 6% 5% 6% 8% 7% 7% 11% 45%	2457
	21st to end	Night	4 3 8% 5% 5% 5% 5% 7% 9% 48%	1980
March	1st to 10th	Night	5% 2 9% 5% 5% 6% 5% 7% 8% 48%	5270
	11th to 20th	Night	1 6% 4 6% 3 3 3 3 7% 10% 54%	5000
	21st to end	Night	1 7% 3 6% 4 4 6% 5% 9% 10% 44%	5260
April	1st to 10th	Night	1 7% 3 6% 5% 5% 4 4 6% 8% 52%	2000
	11th to 20th	Night	4 10% 3 6% 4 5% 4 4 6% 8% 46%	1977
	21st to end	Night	4 9% 3 6% 5% 3 3 4 5% 8% 49%	2000
May	1st to 10th	Night	5% 11% 3 6% 4 4 4 3 6% 8% 46%	4002
	11th to 20th	Night	4 5% 2 6% 4 4 5% 5% 8% 10% 47%	3617
	21st to end	Night	3 6% 3 6% 4 4 5% 4 6% 8% 51%	3972
June	1st to 10th	Night	3 2 1 4 2 3 5% 4 8% 9% 58%	1600
	11th to 20th	Night	3 3 2 3 3 3 4 3 6% 8% 62%	1600
	21st to end	Night	2 3 2 4 3 3 3 2 5% 7% 65%	1600
July	1st to 10th	Night	2 3 1 4 4 4 4 4 6% 9% 58%	3640
	11th to 20th	Night	1 2 1 3 3 4 5% 5% 9% 10% 56%	3640
	21st to end	Night	1 2 1 5% 3 5% 6% 5% 7% 10% 56%	4141
August	1st to 10th	Night	2 3 1 5% 4 4 4 4 7% 10% 56%	4033
	11th to 20th	Night	1 3 2 5% 4 4 5% 5% 7% 9% 56%	4263
	21st to end	Night	3 4 2 6% 4 4 5% 5% 7% 8% 51%	4993
September	1st to 10th	Night	4 3 1 4 3 3 4 3 4 7% 64%	2000
	11th to 20th	Night	4 3 1 4 3 4 3 2 5% 7% 63%	2000
	21st to end	Night	5% 3 1 4 3 2 2 3 4 6% 66%	2244
October	1st to 10th	Night	3 3 1 2 2 2 2 2 3 6% 75%	3920
	11th to 20th	Night	2 4 2 4 3 4 4 3 6% 9% 59%	3898
	21st to end	Night	3 5% 2 4 3 2 3 3 5% 7% 63%	4284
November	1st to 10th	Night	1 3 1 4 3 3 5% 3 6% 9% 61%	2665
	11th to 20th	Night	1 4 2 5% 4 4 5% 4 6% 9% 56%	2772
	21st to end	Night	1 5% 2 5% 4 3 4 5% 6% 9% 55%	2940
December	1st to 10th	Night	2 1 4 3 4 3 3 7% 8% 64%	4710
	11th to 20th	Night	3 1 4 3 4 5% 5% 10% 11% 55%	5280
	21st to end	Night	5% 3 7% 5% 5% 6% 6% 12% 12% 38%	6974

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	18% 35% 13% 20% 12% 2	3639
	11th to 20th	Day	23% 35% 13% 12% 13% 3	3794
	21st to end	Day	15% 33% 12% 15% 19% 5%	4510
February	1st to 10th	Day	12% 66% 7% 7% 5% 2	1800
	11th to 20th	Day	9% 65% 7% 12% 5% 1	1839
	21st to end	Day	12% 64% 6% 8% 8% 1	1650
March	1st to 10th	Day	22% 33% 8% 17% 14% 7%	4592
	11th to 20th	Day	19% 32% 10% 26% 12%	5000
	21st to end	Day	20% 34% 15% 25% 5% 1	5705
April	1st to 10th	Day	13% 64% 6% 11% 5% 1	2400
	11th to 20th	Day	15% 64% 5% 8% 6% 2	2374
	21st to end	Day	18% 64% 4 10% 4	2400
May	1st to 10th	Day	33% 33% 7% 13% 12% 2	5974
	11th to 20th	Day	20% 34% 9% 19% 17% 1	6302
	21st to end	Day	20% 33% 9% 20% 17% 2	6926
June	1st to 10th	Day	9% 64% 6% 10% 9% 2	2800
	11th to 20th	Day	9% 63% 5% 9% 10% 4	2800
	21st to end	Day	11% 61% 4 8% 12% 4	2800
July	1st to 10th	Day	15% 26% 7% 12% 19% 22%	6271
	11th to 20th	Day	18% 30% 8% 18% 17% 10%	6265
	21st to end	Day	20% 28% 8% 13% 17% 13%	6533
August	1st to 10th	Day	17% 40% 8% 17% 11% 8%	4208
	11th to 20th	Day	18% 39% 8% 12% 18% 6%	4043
	21st to end	Day	16% 38% 6% 12% 16% 11%	4311
September	1st to 10th	Day	12% 58% 4 10% 12% 4	2400
	11th to 20th	Day	9% 58% 4 12% 12% 4	2400
	21st to end	Day	11% 57% 3 10% 14% 4	2151
October	1st to 10th	Day	7% 35% 3 10% 30% 15%	3270
	11th to 20th	Day	14% 37% 5% 25% 16% 3	3250
	21st to end	Day	17% 37% 5% 27% 14% 1	3470
November	1st to 10th	Day	11% 56% 7% 15% 9% 2	1853
	11th to 20th	Day	9% 57% 6% 16% 10% 2	1844
	21st to end	Day	14% 57% 6% 15% 8% 1	1680
December	1st to 10th	Day	10% 37% 8% 30% 15% 1	2700
	11th to 20th	Day	9% 34% 17% 31% 8% 1	3080
	21st to end	Day	20% 30% 12% 20% 15% 3	4004
January	1st to 10th	Night	21% 33% 15% 18% 9% 5%	6327
	11th to 20th	Night	17% 37% 15% 13% 15% 3	6230
	21st to end	Night	15% 34% 15% 14% 17% 5%	6468
February	1st to 10th	Night	9% 69% 8% 8% 5% 1	2600
	11th to 20th	Night	8% 66% 8% 12% 6% 1	2458
	21st to end	Night	9% 65% 7% 8% 10% 2	1980
March	1st to 10th	Night	19% 33% 9% 16% 16% 7%	5270
	11th to 20th	Night	16% 31% 10% 22% 20% 1	5000
	21st to end	Night	16% 34% 15% 28% 5%	5260
April	1st to 10th	Night	10% 65% 7% 11% 7% 1	2000
	11th to 20th	Night	13% 64% 5% 10% 8% 1	1977
	21st to end	Night	13% 63% 5% 13% 5%	2000
May	1st to 10th	Night	23% 33% 7% 23% 12% 1	3999
	11th to 20th	Night	16% 34% 12% 24% 11% 2	3618
	21st to end	Night	19% 31% 9% 24% 17%	3972
June	1st to 10th	Night	5% 62% 8% 12% 10% 2	1600
	11th to 20th	Night	7% 62% 5% 11% 10% 5%	1600
	21st to end	Night	8% 60% 4 10% 13% 4	1600
July	1st to 10th	Night	15% 26% 6% 14% 21% 18%	3600
	11th to 20th	Night	13% 28% 10% 28% 14% 8%	3592
	21st to end	Night	15% 27% 9% 19% 16% 13%	4024
August	1st to 10th	Night	16% 38% 13% 16% 12% 7%	2928
	11th to 20th	Night	16% 39% 13% 15% 11% 6%	3080
	21st to end	Night	18% 37% 7% 11% 19% 8%	3597
September	1st to 10th	Night	7% 57% 5% 12% 14% 5%	2000
	11th to 20th	Night	9% 57% 5% 12% 12% 4	2000
	21st to end	Night	10% 58% 3 10% 15% 5%	2244
October	1st to 10th	Night	6% 36% 2 10% 33% 14%	3920
	11th to 20th	Night	14% 36% 6% 22% 19% 3	3898
	21st to end	Night	11% 36% 7% 26% 17% 2	4284
November	1st to 10th	Night	8% 56% 7% 15% 12% 1	2665
	11th to 20th	Night	8% 57% 7% 16% 10% 2	2772
	21st to end	Night	12% 57% 7% 16% 7% 1	2940
December	1st to 10th	Night	7% 37% 9% 31% 13% 2	4710
	11th to 20th	Night	8% 34% 15% 32% 10% 1	5281
	21st to end	Night	18% 32% 13% 23% 12% 2	6974

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	20% 39% 20% 15% 4 1	300
	11th to 20th	Day	14% 54% 21% 10% 2	300
	21st to end	Day	9% 52% 28% 7% 4	330
February	1st to 10th	Day	23% 57% 16% 4 1	300
	11th to 20th	Day	26% 45% 21% 7%	300
	21st to end	Day	26% 45% 21% 8%	249
March	1st to 10th	Day	19% 41% 31% 7% 2	340
	11th to 20th	Day	15% 36% 36% 8% 3	500
	21st to end	Day	16% 44% 28% 9% 2	550
April	1st to 10th	Day	19% 41% 30% 8% 1	500
	11th to 20th	Day	23% 37% 31% 7% 2	492
	21st to end	Day	17% 32% 33% 14% 3 1	500
May	1st to 10th	Day	21% 28% 30% 14% 7%	602
	11th to 20th	Day	16% 19% 34% 19% 10% 2	725
	21st to end	Day	12% 20% 32% 23% 11% 2	789
June	1st to 10th	Day	6% 20% 29% 27% 16% 2	730
	11th to 20th	Day	9% 23% 35% 23% 10% 1	730
	21st to end	Day	6% 17% 34% 27% 14% 2	730
July	1st to 10th	Day	7% 7% 32% 31% 19% 3	721
	11th to 20th	Day	3 8% 41% 28% 18% 3	718
	21st to end	Day	8% 8% 31% 32% 18% 3	720
August	1st to 10th	Day	6% 12% 44% 29% 8% 1	527
	11th to 20th	Day	6% 11% 39% 28% 12% 3	517
	21st to end	Day	6% 15% 34% 29% 13% 2	583
September	1st to 10th	Day	7% 17% 35% 24% 14% 2	530
	11th to 20th	Day	9% 20% 41% 19% 8% 3	530
	21st to end	Day	9% 23% 31% 23% 10% 5%	360
October	1st to 10th	Day	10% 24% 38% 16% 8% 4	330
	11th to 20th	Day	17% 35% 30% 11% 7% 1	330
	21st to end	Day	18% 38% 34% 7% 3 1	363
November	1st to 10th	Day	18% 46% 25% 5% 5%	330
	11th to 20th	Day	22% 41% 29% 7% 1	330
	21st to end	Day	17% 42% 28% 9% 2 1	330
December	1st to 10th	Day	28% 39% 25% 5% 2 1	330
	11th to 20th	Day	24% 48% 21% 7%	321
	21st to end	Day	24% 43% 22% 7% 3	330
January	1st to 10th	Night	10% 41% 31% 12% 6% 1	1000
	11th to 20th	Night	8% 50% 27% 11% 4 1	955
	21st to end	Night	4 46% 34% 11% 4	880
February	1st to 10th	Night	9% 49% 30% 8% 4	800
	11th to 20th	Night	8% 44% 30% 15% 3	784
	21st to end	Night	12% 47% 29% 9% 2	660
March	1st to 10th	Night	5% 42% 32% 15% 5% 1	800
	11th to 20th	Night	7% 30% 36% 21% 5%	800
	21st to end	Night	7% 35% 37% 15% 5% 1	780
April	1st to 10th	Night	8% 33% 39% 17% 2	600
	11th to 20th	Night	12% 29% 36% 17% 5% 1	593
	21st to end	Night	10% 27% 31% 23% 9% 1	600
May	1st to 10th	Night	11% 20% 33% 24% 12% 1	600
	11th to 20th	Night	12% 13% 28% 31% 15% 1	591
	21st to end	Night	6% 16% 27% 34% 15% 1	650
June	1st to 10th	Night	5% 11% 28% 34% 20% 1	600
	11th to 20th	Night	6% 14% 36% 33% 11%	600
	21st to end	Night	4 9% 26% 44% 17% 1	600
July	1st to 10th	Night	5% 4 21% 40% 29% 1	585
	11th to 20th	Night	3 3 23% 42% 27% 2	582
	21st to end	Night	2 2 15% 47% 31% 3	657
August	1st to 10th	Night	5% 3 22% 45% 24% 1	597
	11th to 20th	Night	4 3 21% 46% 24% 2	594
	21st to end	Night	4 6% 18% 39% 30% 3	660
September	1st to 10th	Night	6% 6% 25% 37% 23% 3	600
	11th to 20th	Night	6% 10% 29% 37% 15% 3	600
	21st to end	Night	6% 14% 29% 30% 17% 3	675
October	1st to 10th	Night	8% 19% 32% 28% 12% 1	800
	11th to 20th	Night	10% 26% 34% 21% 8% 1	800
	21st to end	Night	10% 33% 36% 14% 5% 1	900
November	1st to 10th	Night	9% 40% 34% 13% 4 1	1025
	11th to 20th	Night	11% 45% 32% 9% 2	1050
	21st to end	Night	8% 39% 37% 13% 3	1050
December	1st to 10th	Night	13% 44% 30% 10% 2	1050
	11th to 20th	Night	13% 46% 29% 10% 2	1036
	21st to end	Night	12% 47% 26% 11% 3	1100

Page generated at 2025-12-14 23:13:55. Version ac07

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