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 2026-09-29.

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	12% 7% 3 7% 5% 5% 5% 4 6% 8% 37%	148682
	Night	13% 8% 3 7% 4 4 4 4 6% 8% 39%	142730
Transparency	Day	42% 7% 13% 19% 15% 5%	152445
	Night	41% 7% 13% 19% 16% 5%	147039
Seeing	Day	19% 12% 23% 21% 16% 8%	17442
	Night	18% 11% 18% 29% 20% 4	27417

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	17% 11% 4 7% 4 3 3 3 5% 5% 39%	5258
	11th to 20th	Day	10% 7% 4 8% 4 3 2 2 3 4 52%	5280
	21st to end	Day	18% 12% 4 8% 4 3 3 2 4 5% 37%	5795
February	1st to 10th	Day	16% 10% 3 6% 4 4 4 4 4 5% 38%	2100
	11th to 20th	Day	21% 8% 3 7% 6% 4 3 3 5% 5% 35%	2048
	21st to end	Day	21% 8% 2 7% 4 4 4 4 4 5% 37%	1730
March	1st to 10th	Day	18% 8% 3 6% 5% 4 4 3 5% 6% 36%	4768
	11th to 20th	Day	11% 7% 2 6% 4 3 3 3 5% 6% 51%	5090
	21st to end	Day	14% 8% 3 7% 5% 4 4 3 4 5% 43%	5586
April	1st to 10th	Day	12% 6% 2 7% 5% 4 5% 5% 7% 7% 40%	2336
	11th to 20th	Day	12% 6% 3 7% 5% 4 4 4 5% 7% 44%	2510
	21st to end	Day	13% 6% 3 6% 5% 4 5% 4 5% 8% 42%	2730
May	1st to 10th	Day	16% 9% 3 7% 5% 4 5% 4 6% 8% 33%	7616
	11th to 20th	Day	12% 8% 3 9% 6% 6% 6% 5% 7% 7% 31%	7626
	21st to end	Day	13% 9% 4 10% 7% 6% 6% 5% 6% 8% 26%	8391
June	1st to 10th	Day	11% 7% 3 8% 6% 6% 7% 5% 7% 9% 31%	2730
	11th to 20th	Day	7% 5% 2 7% 7% 6% 6% 6% 10% 10% 35%	2730
	21st to end	Day	8% 5% 2 7% 7% 5% 6% 7% 8% 10% 33%	2730
July	1st to 10th	Day	6% 5% 2 7% 6% 6% 7% 6% 9% 12% 34%	7680
	11th to 20th	Day	9% 7% 3 8% 6% 7% 8% 6% 9% 11% 26%	7680
	21st to end	Day	12% 7% 3 9% 6% 7% 7% 6% 8% 10% 24%	8340
August	1st to 10th	Day	9% 7% 3 8% 7% 6% 8% 6% 9% 12% 25%	6014
	11th to 20th	Day	6% 4 2 5% 4 4 5% 5% 8% 14% 43%	5794
	21st to end	Day	7% 4 2 6% 4 5% 6% 5% 8% 9% 45%	6057
September	1st to 10th	Day	10% 8% 3 7% 5% 6% 5% 5% 7% 8% 36%	2310
	11th to 20th	Day	12% 7% 2 7% 6% 5% 6% 4 7% 8% 36%	2310
	21st to end	Day	12% 6% 2 6% 5% 4 5% 4 7% 7% 41%	2288
October	1st to 10th	Day	10% 5% 2 5% 4 4 4 4 5% 6% 51%	2200
	11th to 20th	Day	11% 6% 1 4 3 3 4 3 3 5% 54%	2045
	21st to end	Day	13% 5% 2 5% 3 3 3 2 4 6% 53%	2200
November	1st to 10th	Day	11% 5% 1 5% 2 3 4 3 4 6% 55%	1882
	11th to 20th	Day	12% 6% 2 4 3 3 3 4 6% 7% 49%	1890
	21st to end	Day	14% 8% 3 6% 4 3 4 3 4 5% 45%	1890
December	1st to 10th	Day	18% 8% 2 4 3 3 4 3 5% 5% 45%	3020
	11th to 20th	Day	18% 9% 3 6% 4 5% 5% 4 5% 5% 36%	3463
	21st to end	Day	13% 8% 5% 7% 4 4 4 3 5% 8% 38%	4565
January	1st to 10th	Night	15% 11% 4 6% 4 4 3 3 4 6% 40%	7635
	11th to 20th	Night	16% 9% 3 6% 3 3 3 2 4 6% 45%	7680
	21st to end	Night	17% 13% 4 6% 3 3 3 2 5% 5% 38%	8383
February	1st to 10th	Night	15% 9% 3 6% 4 4 4 3 5% 7% 40%	2520
	11th to 20th	Night	20% 10% 4 7% 4 4 4 3 4 5% 36%	2458
	21st to end	Night	21% 10% 4 7% 3 4 4 3 4 6% 35%	2076
March	1st to 10th	Night	17% 13% 3 7% 5% 5% 4 4 4 6% 32%	5290
	11th to 20th	Night	11% 6% 1 5% 3 3 4 4 5% 8% 49%	5090
	21st to end	Night	11% 9% 3 7% 4 5% 4 4 5% 6% 42%	5588
April	1st to 10th	Night	13% 7% 3 5% 4 4 4 3 6% 8% 45%	2300
	11th to 20th	Night	12% 6% 3 6% 3 3 4 3 5% 7% 48%	2059
	21st to end	Night	11% 7% 3 6% 4 5% 4 4 6% 6% 45%	1890
May	1st to 10th	Night	14% 9% 3 8% 6% 5% 5% 5% 6% 8% 32%	5237
	11th to 20th	Night	13% 9% 3 9% 5% 5% 5% 4 6% 8% 34%	5234
	21st to end	Night	13% 9% 4 10% 6% 6% 6% 5% 6% 8% 28%	5761
June	1st to 10th	Night	8% 8% 2 8% 6% 5% 5% 5% 8% 9% 36%	1890
	11th to 20th	Night	6% 6% 1 5% 5% 4 6% 4 8% 11% 43%	1890
	21st to end	Night	7% 6% 2 5% 4 4 6% 5% 8% 11% 42%	1890
July	1st to 10th	Night	8% 6% 2 7% 6% 6% 6% 5% 7% 12% 36%	5278
	11th to 20th	Night	9% 8% 3 9% 6% 6% 7% 5% 9% 11% 28%	5277
	21st to end	Night	13% 8% 4 8% 5% 5% 6% 5% 7% 10% 29%	5736
August	1st to 10th	Night	8% 6% 2 8% 7% 6% 6% 6% 9% 14% 29%	4135
	11th to 20th	Night	9% 5% 2 6% 4 4 4 4 7% 11% 44%	4234
	21st to end	Night	6% 4 2 5% 4 5% 5% 5% 8% 11% 46%	5046
September	1st to 10th	Night	9% 7% 2 7% 6% 5% 5% 4 7% 9% 40%	2299
	11th to 20th	Night	10% 6% 3 6% 5% 5% 5% 5% 7% 9% 40%	2310
	21st to end	Night	10% 6% 2 7% 4 4 5% 4 6% 8% 45%	2289
October	1st to 10th	Night	11% 5% 3 5% 3 3 4 3 4 6% 54%	2200
	11th to 20th	Night	11% 6% 2 5% 4 3 4 3 5% 6% 52%	2355
	21st to end	Night	11% 8% 2 5% 3 4 4 2 4 5% 53%	2640
November	1st to 10th	Night	11% 6% 2 5% 4 3 4 3 6% 6% 51%	2635
	11th to 20th	Night	14% 8% 2 5% 4 3 3 3 4 5% 49%	2730
	21st to end	Night	15% 9% 2 6% 4 3 3 4 5% 6% 43%	2730
December	1st to 10th	Night	17% 8% 3 6% 4 3 3 3 6% 6% 40%	4380
	11th to 20th	Night	19% 11% 4 7% 4 3 4 3 4 6% 35%	4952
	21st to end	Night	14% 11% 5% 9% 5% 4 4 3 6% 7% 33%	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	44% 5% 8% 19% 20% 4	5259
	11th to 20th	Day	33% 6% 5% 12% 31% 13%	5280
	21st to end	Day	49% 4 5% 15% 16% 10%	5795
February	1st to 10th	Day	47% 5% 7% 19% 18% 5%	2100
	11th to 20th	Day	50% 5% 6% 17% 18% 5%	2058
	21st to end	Day	49% 5% 7% 13% 20% 6%	1730
March	1st to 10th	Day	47% 4 7% 13% 20% 8%	4768
	11th to 20th	Day	34% 5% 5% 16% 21% 18%	5090
	21st to end	Day	44% 4 7% 26% 15% 5%	5586
April	1st to 10th	Day	40% 6% 12% 21% 17% 4	2336
	11th to 20th	Day	39% 6% 10% 19% 23% 5%	2510
	21st to end	Day	40% 6% 11% 26% 15% 2	2730
May	1st to 10th	Day	47% 7% 13% 21% 11% 1	7651
	11th to 20th	Day	49% 8% 15% 20% 8% 1	7630
	21st to end	Day	55% 8% 10% 16% 10% 1	8405
June	1st to 10th	Day	46% 10% 16% 21% 6% 1	2730
	11th to 20th	Day	40% 10% 19% 19% 11% 1	2730
	21st to end	Day	40% 11% 18% 18% 11% 2	2730
July	1st to 10th	Day	39% 11% 24% 20% 5%	7615
	11th to 20th	Day	48% 13% 24% 12% 2 1	7611
	21st to end	Day	53% 9% 17% 14% 6% 1	8156
August	1st to 10th	Day	48% 12% 17% 18% 4	6001
	11th to 20th	Day	28% 8% 29% 24% 9% 1	5833
	21st to end	Day	33% 9% 15% 28% 14% 1	6057
September	1st to 10th	Day	43% 9% 13% 18% 15% 3	2310
	11th to 20th	Day	43% 8% 13% 19% 15% 2	2310
	21st to end	Day	41% 7% 13% 16% 18% 5%	2288
October	1st to 10th	Day	26% 4 7% 17% 35% 10%	3590
	11th to 20th	Day	22% 3 6% 18% 26% 25%	3311
	21st to end	Day	27% 4 6% 25% 24% 13%	3538
November	1st to 10th	Day	31% 4 9% 17% 29% 10%	1882
	11th to 20th	Day	34% 4 6% 21% 26% 9%	1890
	21st to end	Day	40% 5% 7% 17% 25% 6%	1890
December	1st to 10th	Day	41% 4 5% 17% 25% 7%	3020
	11th to 20th	Day	48% 5% 8% 16% 18% 6%	3460
	21st to end	Day	40% 7% 11% 25% 15% 2	4565
January	1st to 10th	Night	45% 4 12% 16% 20% 4	7636
	11th to 20th	Night	40% 4 5% 16% 26% 9%	7680
	21st to end	Night	47% 4 6% 15% 18% 9%	8383
February	1st to 10th	Night	43% 4 9% 19% 20% 5%	2520
	11th to 20th	Night	51% 4 6% 17% 18% 5%	2459
	21st to end	Night	50% 5% 8% 15% 17% 5%	2076
March	1st to 10th	Night	49% 8% 7% 13% 18% 5%	5290
	11th to 20th	Night	32% 5% 9% 18% 20% 15%	5090
	21st to end	Night	42% 5% 10% 24% 14% 5%	5588
April	1st to 10th	Night	37% 6% 13% 20% 20% 4	2300
	11th to 20th	Night	36% 4 9% 24% 21% 6%	2059
	21st to end	Night	37% 7% 13% 26% 16% 2	1890
May	1st to 10th	Night	48% 8% 14% 20% 9% 1	5264
	11th to 20th	Night	47% 8% 17% 18% 10%	5235
	21st to end	Night	51% 10% 13% 17% 8% 1	5771
June	1st to 10th	Night	41% 10% 19% 20% 8% 1	1890
	11th to 20th	Night	32% 10% 22% 25% 9% 1	1890
	21st to end	Night	32% 12% 20% 22% 12% 3	1890
July	1st to 10th	Night	39% 11% 26% 20% 4	5235
	11th to 20th	Night	47% 14% 24% 12% 2 1	5226
	21st to end	Night	49% 10% 20% 14% 5% 2	5606
August	1st to 10th	Night	43% 15% 22% 17% 3	4124
	11th to 20th	Night	32% 8% 31% 20% 9%	4261
	21st to end	Night	29% 8% 21% 30% 12% 1	5046
September	1st to 10th	Night	37% 10% 16% 18% 15% 3	2299
	11th to 20th	Night	39% 9% 15% 21% 15% 1	2310
	21st to end	Night	36% 8% 14% 19% 18% 6%	2289
October	1st to 10th	Night	27% 6% 9% 18% 34% 7%	3590
	11th to 20th	Night	23% 4 7% 19% 29% 20%	3828
	21st to end	Night	24% 6% 4 27% 26% 13%	4252
November	1st to 10th	Night	33% 5% 8% 21% 24% 9%	2635
	11th to 20th	Night	36% 5% 6% 18% 25% 10%	2730
	21st to end	Night	41% 5% 7% 21% 21% 6%	2730
December	1st to 10th	Night	43% 4 6% 17% 24% 6%	4380
	11th to 20th	Night	48% 6% 7% 14% 20% 5%	4954
	21st to end	Night	46% 7% 14% 19% 13% 2	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	34% 24% 31% 9% 2	330
	11th to 20th	Day	39% 21% 25% 10% 5%	330
	21st to end	Day	32% 25% 31% 8% 3	363
February	1st to 10th	Day	28% 23% 36% 12% 2	330
	11th to 20th	Day	42% 25% 26% 5% 1	330
	21st to end	Day	36% 23% 32% 8% 2	273
March	1st to 10th	Day	31% 17% 29% 19% 4	414
	11th to 20th	Day	29% 17% 27% 21% 5% 1	540
	21st to end	Day	26% 21% 27% 20% 5% 1	594
April	1st to 10th	Day	24% 14% 29% 21% 10% 2	540
	11th to 20th	Day	17% 21% 27% 20% 12% 2	532
	21st to end	Day	21% 14% 24% 23% 15% 4	540
May	1st to 10th	Day	22% 16% 24% 20% 12% 5%	543
	11th to 20th	Day	17% 9% 24% 25% 16% 9%	567
	21st to end	Day	16% 8% 24% 22% 18% 11%	617
June	1st to 10th	Day	14% 7% 20% 24% 24% 11%	570
	11th to 20th	Day	8% 7% 21% 25% 24% 16%	570
	21st to end	Day	11% 5% 20% 26% 23% 16%	570
July	1st to 10th	Day	8% 5% 11% 26% 29% 21%	565
	11th to 20th	Day	9% 4 11% 24% 30% 22%	564
	21st to end	Day	12% 3 13% 23% 26% 23%	620
August	1st to 10th	Day	14% 8% 13% 25% 21% 19%	566
	11th to 20th	Day	11% 6% 11% 26% 28% 19%	559
	21st to end	Day	12% 5% 11% 26% 28% 19%	627
September	1st to 10th	Day	10% 4 16% 25% 32% 14%	570
	11th to 20th	Day	14% 4 15% 23% 30% 14%	570
	21st to end	Day	13% 7% 20% 25% 27% 8%	562
October	1st to 10th	Day	14% 6% 22% 30% 20% 8%	530
	11th to 20th	Day	17% 11% 23% 28% 18% 3	530
	21st to end	Day	20% 11% 26% 25% 16% 2	583
November	1st to 10th	Day	18% 15% 33% 22% 9% 4	360
	11th to 20th	Day	21% 22% 32% 19% 6% 1	330
	21st to end	Day	20% 23% 35% 15% 7% 1	330
December	1st to 10th	Day	35% 21% 28% 12% 3 1	330
	11th to 20th	Day	29% 17% 33% 16% 5% 1	330
	21st to end	Day	29% 21% 32% 14% 3 1	363
January	1st to 10th	Night	28% 15% 26% 25% 5%	840
	11th to 20th	Night	25% 21% 22% 25% 7%	840
	21st to end	Night	24% 18% 29% 27% 3	924
February	1st to 10th	Night	22% 16% 25% 32% 5%	840
	11th to 20th	Night	29% 18% 28% 23% 2	823
	21st to end	Night	28% 20% 26% 23% 3	692
March	1st to 10th	Night	22% 16% 28% 29% 5%	840
	11th to 20th	Night	22% 16% 23% 30% 7% 1	840
	21st to end	Night	20% 16% 26% 28% 10%	924
April	1st to 10th	Night	18% 15% 27% 29% 10% 1	830
	11th to 20th	Night	17% 11% 21% 33% 16% 1	623
	21st to end	Night	14% 10% 22% 35% 19% 2	630
May	1st to 10th	Night	16% 8% 20% 35% 20% 2	630
	11th to 20th	Night	15% 8% 14% 34% 24% 4	621
	21st to end	Night	13% 5% 11% 33% 31% 7%	683
June	1st to 10th	Night	11% 4 10% 35% 32% 7%	630
	11th to 20th	Night	8% 4 7% 33% 33% 14%	630
	21st to end	Night	9% 2 7% 30% 43% 9%	630
July	1st to 10th	Night	9% 4 6% 23% 47% 11%	615
	11th to 20th	Night	11% 4 5% 21% 42% 17%	612
	21st to end	Night	11% 3 5% 22% 43% 15%	690
August	1st to 10th	Night	11% 4 6% 23% 43% 12%	627
	11th to 20th	Night	11% 3 6% 27% 42% 10%	624
	21st to end	Night	12% 2 7% 26% 41% 12%	693
September	1st to 10th	Night	11% 4 10% 28% 38% 10%	829
	11th to 20th	Night	14% 3 12% 29% 35% 6%	840
	21st to end	Night	13% 5% 12% 34% 32% 4	833
October	1st to 10th	Night	14% 6% 17% 30% 26% 7%	800
	11th to 20th	Night	16% 9% 19% 33% 22% 3	800
	21st to end	Night	16% 13% 17% 35% 17% 3	880
November	1st to 10th	Night	14% 10% 21% 33% 19% 3	820
	11th to 20th	Night	19% 14% 20% 32% 13% 2	840
	21st to end	Night	21% 16% 17% 31% 13% 1	840
December	1st to 10th	Night	26% 15% 23% 28% 8% 1	840
	11th to 20th	Night	23% 15% 22% 32% 7% 1	840
	21st to end	Night	27% 15% 23% 30% 5%	924

Page generated at 2026-09-26 04:18:44. Version ac07

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