Fry Family Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Fry Family Park clear sky chart from 2005-11-06 to 2026-07-01.

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	16% 11% 4 9% 5% 5% 4 4 5% 7% 30%	137262
	Night	16% 12% 4 9% 5% 4 4 3 5% 6% 31%	135082
Transparency	Day	51% 7% 11% 19% 11% 1	140906
	Night	52% 6% 11% 19% 11% 1	139510
Seeing	Day	22% 14% 28% 20% 12% 4	16780
	Night	21% 12% 27% 26% 12% 1	26710

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% 20% 6% 20% 5% 4 3 2 4 5% 14%	5258
	11th to 20th	Day	12% 21% 8% 18% 8% 5% 4 2 3 4 15%	5280
	21st to end	Day	18% 17% 6% 13% 10% 7% 4 2 3 4 14%	5780
February	1st to 10th	Day	18% 17% 5% 11% 7% 4 3 3 4 4 23%	1890
	11th to 20th	Day	16% 14% 6% 14% 6% 4 4 3 4 5% 23%	1902
	21st to end	Day	17% 17% 4 11% 5% 4 3 4 4 6% 27%	1730
March	1st to 10th	Day	17% 15% 5% 11% 5% 4 4 3 5% 5% 26%	4967
	11th to 20th	Day	13% 9% 4 9% 5% 5% 4 3 5% 6% 37%	5090
	21st to end	Day	21% 11% 4 9% 5% 4 4 3 5% 5% 29%	5586
April	1st to 10th	Day	16% 13% 3 8% 5% 4 4 3 5% 8% 30%	2354
	11th to 20th	Day	16% 12% 3 7% 5% 5% 4 3 5% 7% 34%	2638
	21st to end	Day	20% 10% 3 8% 5% 4 3 3 6% 7% 33%	2730
May	1st to 10th	Day	21% 9% 3 9% 6% 5% 5% 4 6% 6% 27%	7616
	11th to 20th	Day	17% 8% 3 8% 5% 4 5% 4 6% 8% 32%	7626
	21st to end	Day	21% 7% 3 6% 4 4 5% 4 5% 7% 34%	8391
June	1st to 10th	Day	13% 7% 3 7% 5% 4 5% 4 6% 8% 37%	2924
	11th to 20th	Day	13% 7% 3 7% 6% 6% 5% 5% 6% 9% 34%	2940
	21st to end	Day	13% 6% 2 6% 5% 5% 5% 6% 7% 9% 37%	2866
July	1st to 10th	Day	9% 7% 2 7% 4 5% 5% 4 6% 9% 41%	5900
	11th to 20th	Day	10% 7% 3 7% 5% 6% 5% 5% 7% 10% 35%	5900
	21st to end	Day	12% 6% 2 7% 5% 5% 5% 4 7% 9% 38%	6424
August	1st to 10th	Day	13% 7% 2 7% 6% 5% 7% 5% 6% 9% 33%	4234
	11th to 20th	Day	11% 7% 2 7% 5% 5% 5% 5% 8% 9% 36%	4174
	21st to end	Day	8% 4 2 7% 5% 6% 5% 5% 7% 10% 42%	4559
September	1st to 10th	Day	14% 6% 2 6% 4 3 4 3 5% 8% 46%	2300
	11th to 20th	Day	9% 5% 2 7% 3 4 5% 5% 6% 9% 45%	2200
	21st to end	Day	20% 8% 3 6% 4 4 5% 3 5% 6% 37%	2200
October	1st to 10th	Day	15% 6% 2 6% 3 4 4 3 5% 7% 43%	2060
	11th to 20th	Day	17% 9% 2 7% 5% 5% 3 3 5% 6% 37%	2000
	21st to end	Day	22% 11% 3 7% 4 4 4 3 4 6% 33%	2200
November	1st to 10th	Day	12% 10% 3 7% 4 4 5% 3 5% 6% 41%	1879
	11th to 20th	Day	19% 15% 4 7% 5% 4 4 3 4 6% 30%	1885
	21st to end	Day	18% 18% 6% 9% 5% 4 4 3 4 6% 24%	1680
December	1st to 10th	Day	20% 14% 6% 16% 5% 4 4 3 3 4 21%	2680
	11th to 20th	Day	22% 18% 6% 12% 4 3 2 3 4 4 21%	3070
	21st to end	Day	25% 23% 5% 11% 5% 4 4 3 4 4 12%	4349
January	1st to 10th	Night	15% 20% 7% 21% 7% 4 4 2 4 3 13%	7635
	11th to 20th	Night	12% 19% 9% 16% 9% 6% 5% 3 3 3 14%	7680
	21st to end	Night	18% 17% 5% 12% 6% 6% 4 3 3 4 21%	8401
February	1st to 10th	Night	20% 15% 5% 11% 6% 4 4 3 4 5% 23%	2730
	11th to 20th	Night	18% 15% 5% 12% 7% 5% 5% 3 4 5% 23%	2600
	21st to end	Night	19% 15% 5% 12% 5% 4 4 3 4 5% 24%	2076
March	1st to 10th	Night	22% 14% 5% 8% 4 3 3 2 3 4 32%	5104
	11th to 20th	Night	14% 11% 4 6% 4 4 4 4 6% 7% 37%	5090
	21st to end	Night	18% 12% 4 8% 5% 4 4 3 4 4 34%	5588
April	1st to 10th	Night	20% 12% 3 6% 4 4 4 3 5% 6% 32%	2265
	11th to 20th	Night	14% 11% 4 8% 5% 4 4 3 6% 7% 34%	1949
	21st to end	Night	17% 10% 2 7% 4 3 4 3 6% 7% 37%	1890
May	1st to 10th	Night	24% 10% 3 7% 5% 4 4 3 6% 6% 27%	5237
	11th to 20th	Night	16% 9% 3 7% 4 4 3 3 5% 8% 38%	5234
	21st to end	Night	21% 7% 2 6% 4 4 4 3 6% 7% 36%	5761
June	1st to 10th	Night	9% 6% 2 8% 5% 4 4 3 7% 8% 44%	1691
	11th to 20th	Night	10% 6% 3 6% 4 5% 4 4 7% 9% 41%	1680
	21st to end	Night	11% 5% 2 6% 5% 4 5% 4 7% 8% 42%	1745
July	1st to 10th	Night	11% 7% 2 7% 5% 5% 4 4 6% 8% 42%	4058
	11th to 20th	Night	11% 6% 2 6% 5% 5% 5% 5% 7% 9% 38%	4057
	21st to end	Night	8% 6% 3 8% 5% 5% 5% 4 6% 7% 43%	4427
August	1st to 10th	Night	10% 8% 3 7% 6% 5% 5% 4 7% 8% 37%	2915
	11th to 20th	Night	13% 7% 3 7% 4 4 4 3 5% 6% 44%	2875
	21st to end	Night	7% 5% 2 6% 5% 5% 6% 5% 7% 9% 43%	3305
September	1st to 10th	Night	12% 6% 1 5% 3 3 3 3 5% 6% 52%	2096
	11th to 20th	Night	10% 4 2 5% 3 4 4 3 6% 8% 53%	2200
	21st to end	Night	17% 7% 2 7% 4 3 3 3 5% 7% 42%	2200
October	1st to 10th	Night	13% 6% 2 6% 4 4 4 4 6% 6% 46%	2339
	11th to 20th	Night	17% 8% 3 7% 4 4 4 3 5% 7% 38%	2400
	21st to end	Night	24% 9% 2 6% 3 3 4 3 5% 6% 35%	2640
November	1st to 10th	Night	14% 8% 2 6% 4 4 3 3 5% 7% 43%	2636
	11th to 20th	Night	18% 14% 3 8% 4 4 4 3 5% 6% 31%	2730
	21st to end	Night	20% 16% 4 8% 4 4 4 3 4 6% 26%	2940
December	1st to 10th	Night	17% 15% 8% 12% 6% 4 5% 3 5% 5% 20%	4720
	11th to 20th	Night	20% 21% 8% 11% 4 3 3 3 4 5% 20%	5345
	21st to end	Night	24% 21% 6% 9% 5% 4 4 3 4 5% 16%	6843

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	73% 5% 10% 9% 3	5259
	11th to 20th	Day	73% 4 8% 8% 7%	5280
	21st to end	Day	75% 4 6% 12% 3	5780
February	1st to 10th	Day	64% 6% 8% 14% 7% 1	1890
	11th to 20th	Day	63% 6% 8% 14% 8%	1911
	21st to end	Day	59% 5% 12% 16% 7% 1	1730
March	1st to 10th	Day	58% 6% 9% 21% 6%	4967
	11th to 20th	Day	46% 7% 11% 26% 8% 2	5090
	21st to end	Day	55% 6% 9% 18% 12% 1	5586
April	1st to 10th	Day	51% 7% 12% 17% 11% 1	2354
	11th to 20th	Day	50% 6% 12% 16% 14% 2	2638
	21st to end	Day	51% 6% 10% 21% 10% 1	2730
May	1st to 10th	Day	55% 7% 11% 18% 7% 3	7651
	11th to 20th	Day	49% 7% 13% 21% 11% 1	7630
	21st to end	Day	47% 8% 10% 17% 14% 4	8405
June	1st to 10th	Day	43% 8% 14% 22% 13% 1	2924
	11th to 20th	Day	44% 9% 13% 21% 12% 1	2940
	21st to end	Day	40% 10% 13% 22% 13% 1	2866
July	1st to 10th	Day	38% 7% 11% 28% 14% 2	5835
	11th to 20th	Day	41% 8% 14% 23% 13% 1	5831
	21st to end	Day	40% 7% 13% 20% 18% 2	6240
August	1st to 10th	Day	45% 9% 14% 22% 10%	4221
	11th to 20th	Day	40% 9% 11% 28% 11% 1	4213
	21st to end	Day	34% 9% 14% 30% 11% 2	4559
September	1st to 10th	Day	36% 7% 13% 21% 19% 3	2300
	11th to 20th	Day	34% 8% 15% 26% 16% 2	2200
	21st to end	Day	47% 6% 12% 19% 15% 1	2200
October	1st to 10th	Day	30% 5% 12% 31% 21% 1	3359
	11th to 20th	Day	44% 6% 11% 20% 15% 4	3240
	21st to end	Day	40% 5% 13% 26% 16% 1	3538
November	1st to 10th	Day	43% 5% 11% 24% 15% 2	1879
	11th to 20th	Day	55% 5% 10% 19% 8% 3	1885
	21st to end	Day	61% 6% 11% 15% 6% 1	1680
December	1st to 10th	Day	67% 5% 13% 11% 4	2680
	11th to 20th	Day	67% 4 10% 13% 5%	3066
	21st to end	Day	76% 5% 7% 9% 3	4349
January	1st to 10th	Night	76% 5% 8% 9% 3	7636
	11th to 20th	Night	73% 5% 8% 9% 5%	7680
	21st to end	Night	67% 4 9% 13% 6% 1	8401
February	1st to 10th	Night	63% 6% 10% 15% 6%	2730
	11th to 20th	Night	63% 5% 10% 15% 7%	2602
	21st to end	Night	63% 5% 9% 13% 8% 1	2076
March	1st to 10th	Night	56% 4 10% 21% 9%	5104
	11th to 20th	Night	43% 7% 14% 26% 8% 2	5090
	21st to end	Night	51% 5% 10% 19% 13% 1	5588
April	1st to 10th	Night	51% 7% 11% 17% 13% 2	2265
	11th to 20th	Night	47% 7% 12% 16% 15% 2	1949
	21st to end	Night	46% 6% 13% 19% 15% 2	1890
May	1st to 10th	Night	55% 7% 9% 17% 9% 3	5264
	11th to 20th	Night	44% 7% 11% 23% 14% 1	5235
	21st to end	Night	45% 8% 12% 20% 13% 2	5771
June	1st to 10th	Night	36% 8% 11% 23% 18% 3	1691
	11th to 20th	Night	37% 8% 15% 22% 16% 2	1680
	21st to end	Night	36% 9% 14% 23% 17% 1	1745
July	1st to 10th	Night	39% 6% 11% 23% 18% 3	4015
	11th to 20th	Night	39% 8% 17% 24% 12% 1	4006
	21st to end	Night	37% 8% 12% 19% 22% 2	4297
August	1st to 10th	Night	42% 8% 14% 22% 12% 1	2904
	11th to 20th	Night	38% 7% 11% 25% 17% 1	2902
	21st to end	Night	33% 9% 14% 29% 13% 2	3305
September	1st to 10th	Night	33% 6% 11% 24% 21% 4	2096
	11th to 20th	Night	28% 7% 14% 27% 22% 2	2200
	21st to end	Night	42% 6% 12% 21% 19% 1	2200
October	1st to 10th	Night	31% 5% 9% 28% 26% 1	3820
	11th to 20th	Night	39% 5% 12% 22% 15% 6%	3899
	21st to end	Night	36% 4 10% 29% 19% 2	4252
November	1st to 10th	Night	40% 6% 12% 23% 16% 3	2636
	11th to 20th	Night	53% 5% 10% 19% 10% 3	2730
	21st to end	Night	59% 5% 12% 18% 5% 1	2940
December	1st to 10th	Night	65% 5% 11% 15% 4	4720
	11th to 20th	Night	67% 4 13% 13% 3	5348
	21st to end	Night	71% 6% 9% 12% 3	6843

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	31% 23% 33% 9% 5%	330
	11th to 20th	Day	36% 27% 28% 5% 2	330
	21st to end	Day	30% 31% 29% 8% 2	363
February	1st to 10th	Day	31% 22% 35% 10% 1	330
	11th to 20th	Day	34% 30% 28% 7% 1	330
	21st to end	Day	30% 30% 34% 6%	273
March	1st to 10th	Day	27% 21% 34% 13% 4	499
	11th to 20th	Day	30% 20% 32% 12% 5% 1	540
	21st to end	Day	32% 20% 28% 16% 3 1	594
April	1st to 10th	Day	27% 21% 31% 14% 6% 1	540
	11th to 20th	Day	27% 20% 29% 15% 7% 3	532
	21st to end	Day	28% 14% 33% 17% 6% 2	540
May	1st to 10th	Day	29% 20% 27% 16% 6% 3	543
	11th to 20th	Day	22% 12% 33% 18% 11% 4	567
	21st to end	Day	18% 9% 28% 24% 16% 5%	617
June	1st to 10th	Day	14% 9% 31% 29% 12% 4	570
	11th to 20th	Day	17% 12% 27% 27% 13% 4	570
	21st to end	Day	12% 11% 30% 29% 14% 4	570
July	1st to 10th	Day	13% 4 21% 29% 21% 12%	525
	11th to 20th	Day	10% 7% 26% 26% 22% 9%	524
	21st to end	Day	12% 5% 24% 30% 20% 10%	576
August	1st to 10th	Day	13% 6% 21% 29% 22% 8%	526
	11th to 20th	Day	13% 6% 21% 28% 22% 10%	519
	21st to end	Day	10% 5% 24% 26% 24% 11%	583
September	1st to 10th	Day	14% 7% 23% 23% 23% 10%	530
	11th to 20th	Day	8% 5% 16% 29% 27% 14%	530
	21st to end	Day	23% 10% 25% 22% 14% 7%	530
October	1st to 10th	Day	13% 9% 28% 25% 19% 5%	530
	11th to 20th	Day	20% 13% 35% 21% 9% 2	530
	21st to end	Day	29% 15% 33% 16% 7% 1	583
November	1st to 10th	Day	20% 20% 33% 17% 8% 2	357
	11th to 20th	Day	31% 18% 29% 15% 6% 1	327
	21st to end	Day	29% 20% 38% 11% 1	220
December	1st to 10th	Day	30% 22% 36% 6% 4 1	220
	11th to 20th	Day	31% 23% 34% 10% 2	220
	21st to end	Day	35% 22% 30% 11% 1	312
January	1st to 10th	Night	27% 22% 34% 15% 3	840
	11th to 20th	Night	30% 20% 33% 15% 3	840
	21st to end	Night	27% 22% 30% 19% 2	924
February	1st to 10th	Night	30% 17% 30% 21% 2	840
	11th to 20th	Night	27% 20% 35% 17% 1	823
	21st to end	Night	28% 19% 36% 15% 2	692
March	1st to 10th	Night	27% 16% 32% 22% 4	840
	11th to 20th	Night	26% 17% 29% 22% 5% 1	840
	21st to end	Night	25% 15% 34% 20% 5% 1	924
April	1st to 10th	Night	28% 14% 31% 22% 5%	840
	11th to 20th	Night	22% 14% 34% 20% 10% 1	705
	21st to end	Night	23% 9% 33% 27% 7%	630
May	1st to 10th	Night	21% 10% 29% 30% 9% 1	630
	11th to 20th	Night	19% 7% 27% 33% 12% 2	621
	21st to end	Night	14% 4 23% 36% 21% 2	683
June	1st to 10th	Night	9% 4 27% 41% 18% 1	431
	11th to 20th	Night	12% 5% 25% 43% 14%	420
	21st to end	Night	12% 4 24% 37% 22% 1	485
July	1st to 10th	Night	9% 4 15% 41% 26% 6%	585
	11th to 20th	Night	9% 3 20% 36% 28% 4	582
	21st to end	Night	10% 4 16% 39% 28% 3	657
August	1st to 10th	Night	8% 3 15% 43% 28% 3	597
	11th to 20th	Night	11% 3 14% 40% 27% 5%	594
	21st to end	Night	10% 3 17% 33% 31% 6%	703
September	1st to 10th	Night	15% 4 18% 30% 28% 4	800
	11th to 20th	Night	10% 3 14% 38% 30% 4	800
	21st to end	Night	20% 6% 23% 29% 20% 3	800
October	1st to 10th	Night	16% 7% 22% 32% 20% 3	800
	11th to 20th	Night	22% 11% 30% 25% 11% 1	800
	21st to end	Night	28% 11% 28% 26% 7%	880
November	1st to 10th	Night	19% 11% 31% 29% 11%	820
	11th to 20th	Night	26% 14% 32% 21% 7% 1	840
	21st to end	Night	29% 15% 31% 19% 6%	840
December	1st to 10th	Night	29% 17% 32% 18% 4	840
	11th to 20th	Night	27% 18% 32% 20% 4	840
	21st to end	Night	32% 15% 32% 19% 2	924

Page generated at 2026-06-28 02:10:43. Version ac07

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