Towns County Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Towns County Park clear sky chart from 2005-11-06 to 2024-11-02.

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% 8% 3 7% 5% 5% 5% 4 6% 7% 37%	100973
	Night	13% 9% 3 7% 4 4 4 4 6% 7% 39%	97928
Transparency	Day	43% 8% 12% 18% 15% 4	100786
	Night	41% 8% 12% 18% 16% 4	97785
Seeing	Day	19% 11% 22% 22% 17% 9%	14908
	Night	17% 11% 17% 29% 21% 4	24921

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	15% 11% 5% 7% 4 3 3 3 6% 7% 36%	2836
	11th to 20th	Day	15% 8% 4 11% 5% 4 3 3 4 5% 38%	2840
	21st to end	Day	20% 13% 3 5% 3 3 3 3 4 4 38%	3125
February	1st to 10th	Day	18% 11% 4 6% 4 4 4 4 4 5% 37%	1900
	11th to 20th	Day	21% 8% 3 7% 6% 3 3 3 5% 5% 35%	1848
	21st to end	Day	23% 9% 2 7% 4 4 3 3 4 5% 36%	1570
March	1st to 10th	Day	22% 10% 2 5% 4 3 4 3 5% 6% 36%	3248
	11th to 20th	Day	13% 7% 2 6% 4 3 4 3 4 5% 49%	3480
	21st to end	Day	15% 10% 3 7% 5% 4 4 3 5% 6% 39%	3815
April	1st to 10th	Day	13% 7% 2 7% 5% 4 5% 5% 7% 7% 40%	2114
	11th to 20th	Day	13% 6% 3 7% 5% 4 4 4 6% 7% 41%	2268
	21st to end	Day	13% 6% 3 6% 6% 4 5% 4 5% 7% 43%	2470
May	1st to 10th	Day	16% 9% 3 7% 5% 5% 5% 4 5% 7% 35%	4082
	11th to 20th	Day	17% 11% 3 9% 5% 5% 5% 4 6% 6% 29%	4081
	21st to end	Day	9% 7% 3 7% 5% 5% 6% 5% 7% 10% 36%	4476
June	1st to 10th	Day	10% 7% 4 8% 7% 6% 7% 5% 7% 9% 30%	2470
	11th to 20th	Day	7% 6% 2 7% 7% 6% 6% 6% 9% 9% 35%	2470
	21st to end	Day	8% 6% 2 8% 7% 5% 6% 6% 8% 10% 33%	2470
July	1st to 10th	Day	7% 6% 2 8% 7% 7% 7% 6% 9% 11% 30%	4120
	11th to 20th	Day	10% 6% 2 7% 6% 6% 7% 5% 8% 9% 32%	4120
	21st to end	Day	15% 10% 4 11% 8% 8% 8% 6% 8% 7% 16%	4466
August	1st to 10th	Day	8% 7% 3 7% 6% 6% 7% 5% 9% 11% 32%	4104
	11th to 20th	Day	9% 5% 2 6% 5% 5% 6% 5% 9% 13% 35%	3932
	21st to end	Day	8% 5% 2 7% 5% 5% 6% 4 7% 7% 45%	4158
September	1st to 10th	Day	11% 8% 3 7% 5% 7% 5% 5% 7% 8% 34%	2090
	11th to 20th	Day	13% 7% 2 8% 6% 6% 5% 4 7% 8% 34%	2090
	21st to end	Day	12% 6% 2 6% 5% 4 5% 4 7% 7% 42%	2090
October	1st to 10th	Day	11% 5% 2 5% 4 4 4 3 5% 6% 51%	2090
	11th to 20th	Day	12% 7% 1 4 3 3 4 3 3 5% 53%	1943
	21st to end	Day	13% 5% 2 5% 3 4 3 2 4 6% 53%	2090
November	1st to 10th	Day	12% 6% 1 5% 2 3 4 3 4 5% 56%	1710
	11th to 20th	Day	12% 6% 3 4 3 4 4 3 5% 7% 49%	1710
	21st to end	Day	15% 8% 2 6% 4 4 4 3 4 5% 45%	1710
December	1st to 10th	Day	21% 9% 3 6% 4 4 4 4 5% 5% 34%	1710
	11th to 20th	Day	16% 8% 3 6% 4 4 4 4 5% 5% 41%	2153
	21st to end	Day	15% 10% 7% 8% 4 4 4 3 5% 7% 34%	3124
January	1st to 10th	Night	15% 13% 4 6% 4 4 3 2 4 6% 39%	4109
	11th to 20th	Night	18% 11% 3 6% 4 3 3 2 5% 7% 38%	4120
	21st to end	Night	21% 15% 4 7% 3 3 3 2 3 4 35%	4528
February	1st to 10th	Night	15% 9% 3 6% 4 4 4 3 5% 7% 40%	2280
	11th to 20th	Night	20% 10% 4 6% 4 4 4 3 4 5% 36%	2218
	21st to end	Night	23% 10% 4 7% 3 4 4 3 4 6% 34%	1884
March	1st to 10th	Night	20% 13% 3 8% 5% 5% 4 3 4 5% 29%	3590
	11th to 20th	Night	13% 7% 2 5% 4 3 4 4 5% 8% 45%	3480
	21st to end	Night	14% 8% 4 7% 5% 4 4 4 5% 6% 39%	3817
April	1st to 10th	Night	13% 7% 3 5% 4 4 4 3 5% 7% 45%	2081
	11th to 20th	Night	13% 6% 3 6% 3 4 4 3 5% 7% 46%	1861
	21st to end	Night	11% 6% 3 5% 3 4 5% 4 5% 6% 46%	1710
May	1st to 10th	Night	13% 9% 3 7% 6% 5% 4 4 5% 8% 35%	2813
	11th to 20th	Night	16% 10% 3 9% 5% 4 5% 3 6% 7% 33%	2812
	21st to end	Night	7% 5% 2 7% 5% 5% 6% 5% 7% 11% 40%	3079
June	1st to 10th	Night	8% 8% 2 8% 6% 5% 5% 5% 8% 9% 35%	1710
	11th to 20th	Night	5% 6% 1 5% 5% 4 6% 4 8% 11% 45%	1710
	21st to end	Night	7% 6% 2 5% 5% 4 6% 5% 7% 10% 42%	1710
July	1st to 10th	Night	8% 6% 3 7% 6% 7% 6% 5% 7% 11% 32%	2840
	11th to 20th	Night	8% 6% 2 6% 5% 5% 6% 5% 9% 11% 36%	2840
	21st to end	Night	14% 10% 4 10% 7% 6% 6% 5% 7% 8% 23%	3087
August	1st to 10th	Night	7% 6% 2 7% 6% 5% 5% 5% 9% 13% 35%	2825
	11th to 20th	Night	12% 6% 2 7% 4 5% 4 4 6% 8% 41%	2879
	21st to end	Night	6% 5% 2 5% 4 4 4 4 7% 9% 48%	3476
September	1st to 10th	Night	9% 7% 2 7% 5% 5% 5% 4 7% 9% 39%	2080
	11th to 20th	Night	11% 7% 3 7% 5% 5% 5% 5% 7% 9% 39%	2090
	21st to end	Night	9% 6% 2 7% 4 4 5% 4 6% 8% 46%	2090
October	1st to 10th	Night	11% 5% 3 5% 3 3 3 3 4 6% 55%	2090
	11th to 20th	Night	12% 6% 2 5% 4 3 4 3 5% 6% 50%	2237
	21st to end	Night	10% 7% 2 5% 3 4 4 2 4 5% 54%	2508
November	1st to 10th	Night	11% 5% 2 5% 4 3 4 3 6% 6% 52%	2390
	11th to 20th	Night	14% 8% 2 5% 4 3 3 3 4 6% 48%	2470
	21st to end	Night	15% 9% 2 6% 4 3 3 4 6% 6% 42%	2470
December	1st to 10th	Night	20% 9% 3 6% 4 4 4 4 5% 7% 33%	2470
	11th to 20th	Night	14% 12% 3 7% 4 3 3 3 4 6% 41%	3042
	21st to end	Night	15% 12% 6% 10% 5% 4 5% 4 5% 7% 27%	4532

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	44% 6% 7% 14% 23% 6%	2837
	11th to 20th	Day	41% 9% 9% 13% 22% 6%	2840
	21st to end	Day	46% 6% 5% 15% 21% 6%	3125
February	1st to 10th	Day	48% 5% 7% 17% 18% 5%	1900
	11th to 20th	Day	49% 5% 6% 16% 18% 6%	1858
	21st to end	Day	50% 5% 8% 13% 19% 6%	1570
March	1st to 10th	Day	47% 4 9% 15% 15% 9%	3248
	11th to 20th	Day	37% 6% 7% 19% 22% 10%	3480
	21st to end	Day	46% 5% 8% 22% 14% 4	3815
April	1st to 10th	Day	40% 6% 12% 20% 18% 4	2114
	11th to 20th	Day	41% 6% 10% 16% 23% 5%	2268
	21st to end	Day	39% 6% 10% 26% 16% 3	2470
May	1st to 10th	Day	46% 8% 12% 19% 13% 2	4120
	11th to 20th	Day	50% 9% 11% 20% 8% 1	4085
	21st to end	Day	39% 10% 14% 22% 14% 1	4489
June	1st to 10th	Day	47% 10% 16% 20% 6% 1	2470
	11th to 20th	Day	40% 10% 18% 20% 11% 1	2470
	21st to end	Day	41% 11% 17% 17% 11% 2	2470
July	1st to 10th	Day	43% 13% 21% 19% 5% 1	4055
	11th to 20th	Day	45% 11% 21% 17% 5% 1	4051
	21st to end	Day	64% 10% 13% 9% 4	4324
August	1st to 10th	Day	41% 10% 18% 24% 6%	4091
	11th to 20th	Day	36% 10% 22% 18% 12% 2	3971
	21st to end	Day	35% 9% 12% 28% 14% 1	4158
September	1st to 10th	Day	44% 9% 12% 17% 15% 3	2090
	11th to 20th	Day	46% 8% 11% 18% 16% 2	2090
	21st to end	Day	41% 7% 13% 16% 18% 6%	2090
October	1st to 10th	Day	33% 5% 10% 17% 28% 7%	2090
	11th to 20th	Day	33% 5% 10% 20% 21% 12%	1943
	21st to end	Day	34% 4 7% 20% 25% 11%	2090
November	1st to 10th	Day	31% 4 8% 15% 30% 11%	1710
	11th to 20th	Day	35% 4 6% 19% 26% 9%	1710
	21st to end	Day	41% 5% 7% 16% 25% 6%	1710
December	1st to 10th	Day	50% 5% 6% 17% 17% 5%	1710
	11th to 20th	Day	42% 5% 8% 13% 23% 8%	2150
	21st to end	Day	44% 8% 10% 19% 16% 3	3124
January	1st to 10th	Night	46% 5% 6% 12% 25% 6%	4109
	11th to 20th	Night	44% 5% 8% 15% 19% 9%	4120
	21st to end	Night	51% 6% 5% 11% 19% 7%	4528
February	1st to 10th	Night	43% 4 10% 18% 20% 5%	2280
	11th to 20th	Night	50% 4 5% 16% 18% 5%	2219
	21st to end	Night	52% 5% 8% 14% 16% 5%	1884
March	1st to 10th	Night	51% 9% 8% 12% 14% 5%	3590
	11th to 20th	Night	34% 6% 11% 20% 19% 9%	3480
	21st to end	Night	45% 5% 9% 21% 15% 5%	3817
April	1st to 10th	Night	37% 5% 12% 21% 21% 4	2081
	11th to 20th	Night	38% 5% 10% 21% 21% 6%	1861
	21st to end	Night	35% 7% 12% 27% 16% 2	1710
May	1st to 10th	Night	43% 11% 14% 20% 11% 1	2840
	11th to 20th	Night	46% 10% 15% 19% 10%	2813
	21st to end	Night	31% 13% 19% 25% 12% 1	3087
June	1st to 10th	Night	41% 11% 19% 20% 8% 1	1710
	11th to 20th	Night	30% 10% 24% 25% 9% 1	1710
	21st to end	Night	33% 12% 19% 21% 12% 3	1710
July	1st to 10th	Night	44% 11% 21% 19% 4	2795
	11th to 20th	Night	38% 13% 26% 18% 4 1	2786
	21st to end	Night	56% 12% 15% 11% 4 1	2988
August	1st to 10th	Night	36% 12% 26% 22% 4	2814
	11th to 20th	Night	38% 9% 25% 16% 12% 1	2906
	21st to end	Night	30% 8% 20% 28% 13% 1	3476
September	1st to 10th	Night	38% 11% 16% 18% 15% 3	2080
	11th to 20th	Night	41% 10% 13% 20% 16% 1	2090
	21st to end	Night	35% 8% 13% 20% 18% 6%	2090
October	1st to 10th	Night	31% 5% 12% 18% 29% 5%	2090
	11th to 20th	Night	34% 6% 10% 19% 21% 9%	2237
	21st to end	Night	33% 5% 5% 21% 26% 10%	2508
November	1st to 10th	Night	32% 4 7% 21% 25% 10%	2390
	11th to 20th	Night	37% 5% 6% 18% 24% 10%	2470
	21st to end	Night	41% 5% 7% 20% 22% 6%	2470
December	1st to 10th	Night	50% 6% 7% 16% 16% 5%	2470
	11th to 20th	Night	41% 7% 7% 14% 25% 6%	3044
	21st to end	Night	50% 9% 10% 15% 14% 2	4532

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	32% 22% 34% 10% 2	270
	11th to 20th	Day	36% 21% 26% 12% 5%	270
	21st to end	Day	28% 28% 31% 9% 4	297
February	1st to 10th	Day	31% 21% 34% 13% 1	270
	11th to 20th	Day	40% 26% 27% 6% 1	270
	21st to end	Day	38% 23% 30% 8% 1	225
March	1st to 10th	Day	29% 17% 29% 20% 5% 1	346
	11th to 20th	Day	27% 17% 27% 22% 6% 1	460
	21st to end	Day	26% 20% 26% 21% 6% 1	506
April	1st to 10th	Day	25% 13% 28% 21% 11% 2	460
	11th to 20th	Day	17% 22% 24% 21% 13% 2	452
	21st to end	Day	20% 15% 21% 24% 15% 5%	460
May	1st to 10th	Day	21% 15% 24% 21% 13% 6%	463
	11th to 20th	Day	17% 8% 22% 25% 16% 11%	487
	21st to end	Day	14% 7% 23% 23% 20% 13%	529
June	1st to 10th	Day	13% 5% 19% 26% 24% 12%	490
	11th to 20th	Day	9% 6% 19% 24% 26% 17%	490
	21st to end	Day	12% 4 21% 25% 21% 17%	490
July	1st to 10th	Day	9% 5% 10% 25% 29% 21%	485
	11th to 20th	Day	9% 4 11% 23% 29% 24%	484
	21st to end	Day	12% 3 11% 22% 27% 25%	532
August	1st to 10th	Day	15% 6% 13% 24% 20% 22%	486
	11th to 20th	Day	12% 6% 10% 24% 29% 19%	479
	21st to end	Day	14% 3 10% 23% 30% 20%	539
September	1st to 10th	Day	11% 3 15% 23% 34% 14%	490
	11th to 20th	Day	16% 4 16% 22% 29% 13%	490
	21st to end	Day	14% 6% 19% 26% 27% 8%	490
October	1st to 10th	Day	15% 6% 20% 30% 20% 8%	490
	11th to 20th	Day	18% 12% 22% 27% 18% 3	490
	21st to end	Day	18% 10% 26% 26% 18% 2	539
November	1st to 10th	Day	17% 12% 33% 24% 10% 4	302
	11th to 20th	Day	20% 22% 31% 20% 6%	270
	21st to end	Day	16% 20% 37% 17% 8% 1	270
December	1st to 10th	Day	35% 17% 29% 14% 4 1	270
	11th to 20th	Day	27% 18% 33% 16% 6% 1	270
	21st to end	Day	30% 21% 31% 14% 4 1	297
January	1st to 10th	Night	27% 16% 26% 25% 6% 1	760
	11th to 20th	Night	25% 19% 22% 26% 8%	760
	21st to end	Night	23% 18% 28% 27% 3	836
February	1st to 10th	Night	22% 16% 24% 33% 6%	760
	11th to 20th	Night	28% 18% 28% 24% 2	743
	21st to end	Night	29% 20% 25% 23% 4	628
March	1st to 10th	Night	22% 17% 27% 29% 6%	760
	11th to 20th	Night	22% 17% 23% 29% 8% 1	760
	21st to end	Night	20% 17% 24% 28% 10%	836
April	1st to 10th	Night	18% 15% 27% 29% 10% 1	751
	11th to 20th	Night	18% 12% 20% 33% 16% 1	563
	21st to end	Night	13% 9% 22% 35% 19% 2	570
May	1st to 10th	Night	16% 8% 19% 34% 22% 2	570
	11th to 20th	Night	15% 7% 14% 33% 27% 4	561
	21st to end	Night	11% 3 10% 34% 34% 8%	617
June	1st to 10th	Night	11% 4 9% 34% 34% 8%	570
	11th to 20th	Night	7% 4 8% 32% 35% 15%	570
	21st to end	Night	9% 2 7% 31% 42% 9%	570
July	1st to 10th	Night	9% 3 6% 23% 46% 11%	555
	11th to 20th	Night	10% 3 6% 21% 43% 17%	552
	21st to end	Night	11% 3 4 21% 45% 16%	624
August	1st to 10th	Night	10% 4 5% 23% 45% 14%	567
	11th to 20th	Night	11% 3 6% 29% 42% 9%	564
	21st to end	Night	13% 2 7% 23% 43% 13%	627
September	1st to 10th	Night	11% 3 10% 27% 39% 10%	750
	11th to 20th	Night	15% 3 12% 29% 34% 6%	760
	21st to end	Night	13% 5% 12% 34% 33% 4	760
October	1st to 10th	Night	14% 6% 17% 29% 27% 7%	760
	11th to 20th	Night	16% 9% 19% 33% 21% 3	760
	21st to end	Night	15% 13% 16% 36% 18% 3	836
November	1st to 10th	Night	13% 9% 19% 34% 20% 3	745
	11th to 20th	Night	19% 15% 19% 32% 13% 3	760
	21st to end	Night	19% 15% 18% 33% 14% 1	760
December	1st to 10th	Night	26% 15% 21% 29% 8% 1	760
	11th to 20th	Night	22% 15% 22% 33% 8% 1	760
	21st to end	Night	27% 15% 22% 31% 5%	836

Page generated at 2024-10-30 01:23:00. Version ac07

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