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 2025-02-25.

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%	108618
	Night	17% 12% 4 9% 5% 4 4 3 5% 6% 31%	110055
Transparency	Day	51% 7% 11% 19% 10% 1	112306
	Night	52% 6% 11% 19% 11% 2	114506
Seeing	Day	21% 14% 28% 20% 12% 4	14977
	Night	21% 11% 27% 27% 12% 1	25016

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	16% 21% 6% 22% 5% 4 2 2 4 4 14%	4056
	11th to 20th	Day	13% 23% 8% 17% 7% 6% 3 2 3 3 15%	4060
	21st to end	Day	21% 20% 7% 11% 8% 5% 4 2 3 4 13%	4466
February	1st to 10th	Day	19% 18% 5% 12% 7% 4 3 3 4 3 22%	1800
	11th to 20th	Day	16% 14% 6% 14% 6% 4 4 3 4 5% 23%	1809
	21st to end	Day	18% 17% 3 11% 5% 4 3 4 3 6% 27%	1610
March	1st to 10th	Day	22% 15% 5% 9% 4 4 3 2 5% 6% 25%	3387
	11th to 20th	Day	14% 11% 4 10% 6% 5% 4 3 5% 5% 33%	3480
	21st to end	Day	22% 11% 4 8% 5% 3 4 3 4 5% 31%	3815
April	1st to 10th	Day	15% 14% 3 7% 5% 4 4 4 5% 8% 31%	2130
	11th to 20th	Day	18% 12% 3 7% 4 5% 4 3 4 6% 35%	2384
	21st to end	Day	20% 10% 3 8% 5% 4 4 3 6% 6% 32%	2470
May	1st to 10th	Day	23% 10% 3 8% 6% 5% 5% 3 5% 6% 28%	4082
	11th to 20th	Day	20% 9% 3 8% 5% 4 4 3 5% 7% 32%	4081
	21st to end	Day	13% 6% 3 6% 5% 4 5% 5% 6% 9% 37%	4476
June	1st to 10th	Day	14% 7% 3 7% 5% 4 5% 4 6% 8% 36%	2646
	11th to 20th	Day	13% 7% 2 6% 6% 6% 5% 5% 6% 9% 35%	2660
	21st to end	Day	13% 5% 2 6% 5% 5% 5% 6% 7% 9% 36%	2594
July	1st to 10th	Day	10% 7% 2 8% 5% 5% 5% 5% 6% 9% 38%	4120
	11th to 20th	Day	9% 5% 2 5% 5% 5% 5% 5% 7% 9% 41%	4120
	21st to end	Day	11% 6% 3 7% 6% 5% 6% 5% 7% 9% 36%	4466
August	1st to 10th	Day	14% 7% 2 7% 6% 5% 7% 5% 6% 9% 32%	4104
	11th to 20th	Day	12% 7% 2 7% 5% 5% 5% 5% 8% 9% 35%	4044
	21st to end	Day	8% 4 2 7% 5% 6% 5% 5% 7% 9% 42%	4419
September	1st to 10th	Day	14% 6% 2 6% 4 3 4 3 5% 8% 45%	2185
	11th to 20th	Day	10% 6% 2 7% 3 4 5% 5% 6% 9% 44%	2090
	21st to end	Day	21% 8% 3 6% 4 3 5% 3 5% 6% 37%	2090
October	1st to 10th	Day	16% 7% 2 6% 4 4 4 3 5% 7% 41%	1957
	11th to 20th	Day	18% 9% 3 7% 5% 5% 3 3 5% 6% 36%	1900
	21st to end	Day	22% 11% 3 7% 4 4 4 3 4 6% 32%	2090
November	1st to 10th	Day	12% 10% 3 7% 4 4 5% 3 5% 6% 41%	1788
	11th to 20th	Day	19% 15% 4 7% 5% 4 4 3 4 6% 30%	1795
	21st to end	Day	19% 18% 5% 9% 5% 4 4 3 4 6% 24%	1600
December	1st to 10th	Day	21% 14% 6% 16% 5% 4 4 3 3 4 21%	2600
	11th to 20th	Day	23% 18% 6% 12% 4 3 2 3 4 4 21%	2990
	21st to end	Day	25% 23% 5% 11% 5% 4 4 3 4 4 12%	4254
January	1st to 10th	Night	16% 20% 7% 23% 6% 3 3 2 3 3 14%	5889
	11th to 20th	Night	13% 22% 9% 15% 9% 5% 5% 3 3 3 13%	5900
	21st to end	Night	22% 18% 6% 13% 6% 3 4 3 3 4 19%	6490
February	1st to 10th	Night	21% 15% 5% 11% 6% 4 4 3 4 5% 23%	2600
	11th to 20th	Night	18% 15% 5% 11% 7% 5% 4 3 4 5% 23%	2473
	21st to end	Night	19% 15% 4 12% 6% 4 4 4 4 5% 24%	1939
March	1st to 10th	Night	24% 13% 4 6% 4 4 3 2 3 5% 33%	3464
	11th to 20th	Night	18% 12% 5% 7% 4 4 4 3 5% 6% 34%	3480
	21st to end	Night	19% 11% 3 7% 4 4 3 3 4 5% 37%	3817
April	1st to 10th	Night	19% 12% 3 5% 4 4 4 3 5% 7% 33%	2049
	11th to 20th	Night	15% 11% 3 7% 5% 4 4 3 6% 6% 35%	1761
	21st to end	Night	17% 10% 2 7% 4 4 4 3 6% 7% 37%	1710
May	1st to 10th	Night	27% 10% 3 7% 5% 4 4 3 5% 6% 26%	2813
	11th to 20th	Night	19% 8% 2 6% 4 4 3 3 5% 7% 39%	2812
	21st to end	Night	11% 5% 1 6% 4 4 4 4 7% 9% 43%	3079
June	1st to 10th	Night	8% 6% 3 8% 5% 4 4 3 6% 9% 43%	1530
	11th to 20th	Night	10% 6% 3 6% 4 5% 4 4 7% 9% 42%	1520
	21st to end	Night	11% 5% 2 6% 5% 4 5% 4 7% 9% 43%	1579
July	1st to 10th	Night	10% 7% 2 7% 4 5% 4 4 5% 9% 43%	2840
	11th to 20th	Night	10% 5% 2 5% 4 4 5% 4 6% 9% 45%	2840
	21st to end	Night	8% 6% 3 8% 5% 5% 6% 4 6% 7% 43%	3087
August	1st to 10th	Night	10% 8% 3 7% 6% 5% 5% 4 7% 8% 36%	2825
	11th to 20th	Night	13% 8% 3 7% 4 4 4 3 5% 7% 44%	2785
	21st to end	Night	6% 5% 2 6% 5% 5% 6% 5% 7% 9% 43%	3204
September	1st to 10th	Night	13% 6% 1 6% 3 3 3 3 5% 6% 51%	1991
	11th to 20th	Night	10% 4 2 5% 3 4 4 3 5% 8% 52%	2090
	21st to end	Night	17% 7% 2 6% 4 3 3 3 5% 7% 43%	2090
October	1st to 10th	Night	13% 6% 2 6% 4 4 4 4 6% 6% 45%	2222
	11th to 20th	Night	17% 9% 3 8% 4 4 4 3 5% 6% 37%	2280
	21st to end	Night	24% 8% 2 6% 3 3 4 3 5% 6% 35%	2508
November	1st to 10th	Night	14% 8% 2 6% 4 4 4 3 5% 7% 43%	2507
	11th to 20th	Night	18% 14% 4 8% 4 4 4 3 5% 6% 31%	2600
	21st to end	Night	20% 16% 4 8% 4 4 4 3 4 6% 26%	2800
December	1st to 10th	Night	17% 15% 8% 12% 6% 4 5% 3 5% 5% 20%	4580
	11th to 20th	Night	20% 21% 8% 11% 4 3 3 2 4 5% 20%	5205
	21st to end	Night	24% 21% 6% 9% 5% 4 4 3 4 5% 16%	6696

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% 6% 9% 8% 3	4057
	11th to 20th	Day	74% 4 8% 8% 5% 1	4060
	21st to end	Day	76% 4 6% 9% 4	4466
February	1st to 10th	Day	66% 6% 8% 14% 7% 1	1800
	11th to 20th	Day	63% 7% 8% 14% 8%	1818
	21st to end	Day	59% 5% 11% 15% 8% 2	1610
March	1st to 10th	Day	60% 6% 10% 19% 5%	3387
	11th to 20th	Day	49% 9% 11% 23% 8% 1	3480
	21st to end	Day	53% 6% 11% 16% 12% 1	3815
April	1st to 10th	Day	50% 7% 12% 18% 11% 2	2130
	11th to 20th	Day	50% 6% 11% 16% 14% 2	2384
	21st to end	Day	52% 7% 10% 20% 10% 2	2470
May	1st to 10th	Day	54% 8% 11% 19% 7% 1	4120
	11th to 20th	Day	49% 8% 13% 20% 10% 1	4085
	21st to end	Day	38% 12% 15% 21% 11% 4	4489
June	1st to 10th	Day	43% 9% 14% 21% 12% 1	2646
	11th to 20th	Day	43% 10% 12% 21% 13% 1	2660
	21st to end	Day	40% 10% 13% 21% 13% 2	2594
July	1st to 10th	Day	41% 8% 12% 23% 14% 2	4055
	11th to 20th	Day	36% 7% 14% 26% 17% 1	4051
	21st to end	Day	42% 8% 15% 16% 17% 2	4324
August	1st to 10th	Day	46% 9% 14% 22% 10%	4091
	11th to 20th	Day	41% 9% 11% 28% 11% 1	4083
	21st to end	Day	35% 9% 14% 30% 11% 2	4419
September	1st to 10th	Day	37% 7% 14% 21% 19% 3	2185
	11th to 20th	Day	35% 9% 14% 25% 15% 2	2090
	21st to end	Day	47% 6% 11% 20% 15%	2090
October	1st to 10th	Day	31% 5% 12% 31% 20% 1	3256
	11th to 20th	Day	45% 6% 11% 20% 14% 4	3140
	21st to end	Day	39% 5% 13% 26% 16% 1	3428
November	1st to 10th	Day	43% 5% 11% 24% 15% 2	1788
	11th to 20th	Day	55% 5% 10% 19% 9% 3	1795
	21st to end	Day	61% 6% 11% 15% 6% 1	1600
December	1st to 10th	Day	67% 5% 13% 11% 4	2600
	11th to 20th	Day	67% 4 10% 13% 5%	2986
	21st to end	Day	76% 5% 7% 9% 3	4254
January	1st to 10th	Night	75% 5% 7% 9% 4	5889
	11th to 20th	Night	74% 5% 9% 7% 4	5900
	21st to end	Night	69% 4 9% 11% 5% 1	6490
February	1st to 10th	Night	64% 6% 10% 14% 6%	2600
	11th to 20th	Night	63% 5% 10% 15% 7%	2475
	21st to end	Night	63% 5% 10% 13% 8% 2	1939
March	1st to 10th	Night	55% 5% 10% 21% 9% 1	3464
	11th to 20th	Night	47% 8% 14% 23% 7% 1	3480
	21st to end	Night	47% 6% 12% 23% 11% 1	3817
April	1st to 10th	Night	49% 7% 11% 17% 13% 2	2049
	11th to 20th	Night	46% 7% 12% 15% 16% 3	1761
	21st to end	Night	45% 6% 13% 18% 16% 2	1710
May	1st to 10th	Night	57% 8% 8% 18% 8% 1	2840
	11th to 20th	Night	44% 8% 12% 22% 12% 1	2813
	21st to end	Night	31% 11% 17% 23% 14% 4	3087
June	1st to 10th	Night	36% 9% 12% 23% 17% 3	1530
	11th to 20th	Night	36% 8% 15% 22% 16% 3	1520
	21st to end	Night	35% 9% 13% 23% 18% 1	1579
July	1st to 10th	Night	38% 7% 12% 22% 17% 4	2795
	11th to 20th	Night	33% 7% 14% 28% 16% 1	2786
	21st to end	Night	38% 8% 12% 17% 21% 3	2988
August	1st to 10th	Night	43% 8% 14% 21% 12% 1	2814
	11th to 20th	Night	39% 7% 11% 24% 18% 1	2812
	21st to end	Night	33% 9% 14% 29% 13% 2	3204
September	1st to 10th	Night	34% 6% 11% 24% 20% 5%	1991
	11th to 20th	Night	29% 7% 13% 26% 22% 2	2090
	21st to end	Night	41% 6% 12% 21% 19% 1	2090
October	1st to 10th	Night	31% 6% 9% 28% 25% 1	3703
	11th to 20th	Night	39% 5% 12% 22% 14% 7%	3779
	21st to end	Night	36% 4 10% 29% 19% 2	4120
November	1st to 10th	Night	40% 6% 12% 23% 16% 3	2507
	11th to 20th	Night	53% 5% 10% 18% 10% 3	2600
	21st to end	Night	58% 5% 12% 18% 6% 1	2800
December	1st to 10th	Night	65% 6% 11% 15% 3	4580
	11th to 20th	Night	67% 4 14% 12% 3	5208
	21st to end	Night	71% 6% 9% 12% 3	6696

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	30% 23% 33% 9% 5%	300
	11th to 20th	Day	33% 28% 31% 6% 3	300
	21st to end	Day	28% 32% 29% 8% 2	330
February	1st to 10th	Day	33% 23% 34% 9% 1	300
	11th to 20th	Day	34% 30% 28% 7% 1	300
	21st to end	Day	32% 29% 33% 6%	237
March	1st to 10th	Day	26% 21% 34% 15% 5%	423
	11th to 20th	Day	29% 19% 32% 13% 5% 1	460
	21st to end	Day	32% 17% 29% 17% 4 1	506
April	1st to 10th	Day	24% 22% 31% 14% 7% 2	460
	11th to 20th	Day	26% 18% 29% 15% 8% 4	452
	21st to end	Day	28% 15% 32% 17% 6% 2	460
May	1st to 10th	Day	27% 20% 26% 17% 8% 3	463
	11th to 20th	Day	22% 11% 33% 18% 12% 4	487
	21st to end	Day	14% 8% 28% 26% 18% 6%	529
June	1st to 10th	Day	14% 8% 30% 30% 13% 4	490
	11th to 20th	Day	16% 10% 26% 29% 15% 4	490
	21st to end	Day	12% 12% 30% 27% 15% 5%	490
July	1st to 10th	Day	13% 4 20% 28% 21% 13%	485
	11th to 20th	Day	11% 7% 26% 26% 22% 9%	484
	21st to end	Day	11% 5% 26% 30% 20% 9%	532
August	1st to 10th	Day	14% 6% 20% 29% 22% 9%	486
	11th to 20th	Day	14% 7% 22% 28% 20% 10%	479
	21st to end	Day	11% 4 22% 26% 25% 12%	539
September	1st to 10th	Day	14% 7% 23% 24% 22% 10%	490
	11th to 20th	Day	9% 6% 17% 30% 26% 12%	490
	21st to end	Day	24% 11% 25% 20% 13% 7%	490
October	1st to 10th	Day	13% 10% 29% 24% 18% 6%	490
	11th to 20th	Day	21% 13% 34% 21% 9% 2	490
	21st to end	Day	29% 14% 32% 17% 7% 1	539
November	1st to 10th	Day	19% 20% 33% 17% 9% 2	326
	11th to 20th	Day	30% 18% 31% 14% 6% 1	297
	21st to end	Day	27% 22% 39% 12% 2	200
December	1st to 10th	Day	30% 23% 36% 6% 5% 2	200
	11th to 20th	Day	30% 22% 36% 10% 3	200
	21st to end	Day	33% 24% 31% 11% 1	283
January	1st to 10th	Night	27% 22% 34% 14% 3	800
	11th to 20th	Night	30% 18% 33% 16% 3	800
	21st to end	Night	28% 21% 30% 19% 2	880
February	1st to 10th	Night	31% 17% 30% 21% 2	800
	11th to 20th	Night	28% 19% 35% 17% 1	783
	21st to end	Night	28% 18% 36% 16% 2	647
March	1st to 10th	Night	25% 15% 32% 23% 4	760
	11th to 20th	Night	25% 17% 29% 23% 5% 1	760
	21st to end	Night	25% 14% 34% 21% 5% 1	836
April	1st to 10th	Night	26% 14% 32% 23% 5%	760
	11th to 20th	Night	22% 14% 34% 20% 10% 1	637
	21st to end	Night	23% 9% 34% 27% 6%	570
May	1st to 10th	Night	21% 10% 29% 30% 10% 1	570
	11th to 20th	Night	20% 6% 25% 34% 13% 2	561
	21st to end	Night	11% 4 22% 38% 23% 3	617
June	1st to 10th	Night	9% 4 27% 42% 17% 1	390
	11th to 20th	Night	12% 4 25% 44% 16% 1	380
	21st to end	Night	11% 4 24% 38% 22% 1	439
July	1st to 10th	Night	9% 4 15% 41% 26% 6%	555
	11th to 20th	Night	9% 2 21% 37% 27% 4	552
	21st to end	Night	10% 4 16% 39% 28% 2	624
August	1st to 10th	Night	9% 3 14% 43% 29% 3	567
	11th to 20th	Night	11% 3 15% 41% 26% 4	564
	21st to end	Night	10% 3 17% 33% 30% 6%	668
September	1st to 10th	Night	16% 4 18% 29% 28% 5%	760
	11th to 20th	Night	11% 3 15% 38% 29% 4	760
	21st to end	Night	20% 6% 23% 29% 19% 3	760
October	1st to 10th	Night	16% 8% 23% 33% 18% 3	760
	11th to 20th	Night	22% 11% 29% 25% 11% 1	760
	21st to end	Night	28% 11% 27% 27% 8%	836
November	1st to 10th	Night	19% 10% 30% 29% 12%	780
	11th to 20th	Night	25% 14% 32% 21% 7% 1	800
	21st to end	Night	28% 15% 31% 19% 6%	800
December	1st to 10th	Night	30% 16% 32% 18% 4	800
	11th to 20th	Night	27% 17% 32% 20% 4	800
	21st to end	Night	31% 14% 32% 20% 2	880

Page generated at 2025-02-22 06:51:39. Version ac07

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