Silver Sands State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Silver Sands State Park clear sky chart from 2005-11-06 to 2024-11-28.

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	17% 6% 2 6% 4 4 4 4 6% 7% 40%	101454
	Night	19% 7% 2 6% 4 4 4 3 5% 6% 41%	98096
Transparency	Day	40% 6% 13% 23% 16% 2	105001
	Night	43% 5% 12% 23% 16% 2	102626
Seeing	Day	18% 6% 25% 30% 17% 4	15107
	Night	20% 8% 29% 29% 12% 2	24173

By Month

Percentage Cloud Cover NE (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% 7% 2 5% 4 4 3 3 4 5% 46%	2517
	11th to 20th	Day	16% 8% 3 7% 5% 5% 3 5% 5% 5% 38%	2520
	21st to end	Day	22% 9% 3 7% 4 4 4 3 6% 6% 33%	2880
February	1st to 10th	Day	17% 7% 2 5% 5% 5% 5% 4 5% 7% 38%	1771
	11th to 20th	Day	15% 6% 2 5% 4 3 4 5% 6% 7% 44%	1848
	21st to end	Day	21% 8% 2 5% 4 4 3 4 5% 6% 38%	1570
March	1st to 10th	Day	27% 8% 2 6% 3 3 3 3 4 5% 35%	3116
	11th to 20th	Day	10% 5% 1 5% 4 4 5% 5% 6% 9% 47%	3266
	21st to end	Day	20% 6% 2 6% 4 4 3 3 5% 6% 40%	4166
April	1st to 10th	Day	19% 8% 2 4 4 4 4 3 6% 6% 38%	2280
	11th to 20th	Day	19% 6% 2 6% 4 4 3 4 5% 7% 42%	2254
	21st to end	Day	20% 6% 2 6% 4 3 4 3 5% 6% 40%	2367
May	1st to 10th	Day	28% 9% 2 5% 3 3 4 3 5% 7% 31%	4106
	11th to 20th	Day	23% 7% 2 6% 4 4 4 3 6% 7% 34%	4266
	21st to end	Day	15% 5% 2 5% 3 3 4 4 6% 8% 46%	4837
June	1st to 10th	Day	18% 6% 1 5% 4 4 5% 4 7% 8% 38%	2660
	11th to 20th	Day	15% 6% 2 5% 4 4 5% 4 6% 9% 39%	2660
	21st to end	Day	12% 7% 2 6% 3 4 5% 4 6% 9% 42%	2660
July	1st to 10th	Day	12% 6% 3 7% 6% 4 5% 5% 7% 11% 35%	4440
	11th to 20th	Day	13% 6% 2 6% 4 4 5% 4 7% 9% 40%	4440
	21st to end	Day	16% 7% 3 8% 5% 4 6% 4 6% 7% 34%	4814
August	1st to 10th	Day	18% 6% 3 7% 4 4 4 4 7% 9% 34%	4243
	11th to 20th	Day	12% 6% 2 6% 4 3 4 3 6% 9% 45%	3730
	21st to end	Day	7% 5% 2 6% 4 4 5% 4 7% 9% 47%	4180
September	1st to 10th	Day	13% 5% 2 5% 5% 4 4 4 5% 6% 47%	2280
	11th to 20th	Day	13% 5% 2 4 3 3 4 4 4 6% 53%	2156
	21st to end	Day	20% 6% 2 6% 4 3 4 4 4 6% 41%	2090
October	1st to 10th	Day	21% 6% 3 5% 4 3 4 3 6% 5% 42%	2052
	11th to 20th	Day	15% 5% 2 5% 3 3 3 3 6% 7% 48%	1898
	21st to end	Day	19% 5% 2 4 4 4 4 3 6% 7% 41%	1881
November	1st to 10th	Day	13% 6% 1 6% 4 3 3 2 4 7% 50%	1761
	11th to 20th	Day	18% 6% 1 4 3 3 3 3 5% 6% 49%	1800
	21st to end	Day	16% 7% 2 5% 3 3 3 4 5% 7% 44%	1747
December	1st to 10th	Day	19% 6% 2 6% 4 4 4 3 7% 6% 38%	1520
	11th to 20th	Day	23% 6% 2 4 3 2 3 2 4 6% 45%	1906
	21st to end	Day	19% 12% 3 6% 4 4 4 3 5% 6% 34%	2772
January	1st to 10th	Night	17% 6% 2 5% 3 3 3 3 4 6% 46%	4429
	11th to 20th	Night	17% 9% 3 6% 4 3 3 3 4 5% 44%	4440
	21st to end	Night	25% 11% 3 6% 3 3 3 3 3 5% 33%	4774
February	1st to 10th	Night	17% 9% 3 6% 4 3 4 3 4 5% 41%	2408
	11th to 20th	Night	17% 8% 3 5% 4 3 3 3 5% 7% 41%	2218
	21st to end	Night	21% 8% 2 4 4 4 3 3 4 5% 42%	1884
March	1st to 10th	Night	26% 11% 2 5% 3 3 3 3 4 5% 35%	3724
	11th to 20th	Night	12% 7% 2 6% 5% 5% 4 3 5% 6% 45%	3689
	21st to end	Night	21% 9% 2 5% 3 4 3 3 5% 5% 41%	3466
April	1st to 10th	Night	19% 6% 2 8% 4 4 4 4 5% 6% 38%	1900
	11th to 20th	Night	21% 6% 2 6% 4 3 4 2 5% 6% 42%	1875
	21st to end	Night	20% 7% 2 6% 4 3 4 3 4 5% 42%	1811
May	1st to 10th	Night	25% 11% 4 6% 4 3 4 3 5% 6% 29%	2834
	11th to 20th	Night	24% 8% 3 7% 5% 4 4 4 5% 7% 30%	2655
	21st to end	Night	19% 7% 2 5% 4 3 4 3 5% 6% 42%	2738
June	1st to 10th	Night	19% 6% 2 5% 4 5% 3 4 5% 6% 40%	1520
	11th to 20th	Night	16% 6% 2 5% 3 4 4 3 6% 9% 41%	1520
	21st to end	Night	14% 6% 2 5% 4 5% 4 3 5% 9% 43%	1520
July	1st to 10th	Night	14% 8% 2 7% 5% 5% 5% 4 7% 8% 35%	2520
	11th to 20th	Night	18% 6% 2 5% 5% 4 5% 4 6% 10% 34%	2520
	21st to end	Night	20% 8% 3 7% 4 4 4 4 6% 7% 33%	2739
August	1st to 10th	Night	23% 6% 3 7% 4 5% 5% 5% 7% 6% 29%	2650
	11th to 20th	Night	14% 7% 2 6% 4 5% 5% 4 6% 7% 39%	3097
	21st to end	Night	9% 4 2 4 4 3 4 3 5% 8% 55%	3476
September	1st to 10th	Night	14% 6% 3 5% 5% 4 4 3 4 7% 44%	1900
	11th to 20th	Night	14% 6% 1 4 4 2 4 2 4 6% 53%	2023
	21st to end	Night	18% 8% 2 5% 4 4 4 3 4 5% 43%	2090
October	1st to 10th	Night	19% 7% 3 6% 4 4 4 2 4 7% 39%	2125
	11th to 20th	Night	15% 5% 2 6% 3 3 3 3 4 6% 49%	2280
	21st to end	Night	21% 8% 2 5% 3 3 3 3 5% 6% 41%	2717
November	1st to 10th	Night	12% 5% 2 6% 4 3 3 3 5% 6% 50%	2537
	11th to 20th	Night	19% 7% 2 4 3 3 3 3 4 6% 47%	2600
	21st to end	Night	16% 5% 2 5% 4 4 3 3 5% 7% 46%	2585
December	1st to 10th	Night	21% 7% 2 5% 3 4 4 3 5% 6% 40%	2660
	11th to 20th	Night	21% 7% 2 4 3 4 3 3 5% 6% 42%	3288
	21st to end	Night	22% 10% 3 6% 3 3 3 3 4 5% 37%	4884

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	39% 4 9% 32% 13% 2	2518
	11th to 20th	Day	45% 6% 12% 24% 12% 1	2520
	21st to end	Day	50% 7% 10% 21% 11% 2	2880
February	1st to 10th	Day	44% 5% 13% 22% 14% 2	1771
	11th to 20th	Day	39% 5% 11% 25% 17% 3	1857
	21st to end	Day	45% 6% 10% 20% 15% 4	1570
March	1st to 10th	Day	50% 4 13% 20% 11% 2	3119
	11th to 20th	Day	29% 9% 13% 32% 15% 1	3266
	21st to end	Day	43% 5% 7% 17% 21% 6%	4166
April	1st to 10th	Day	42% 7% 10% 21% 16% 4	2280
	11th to 20th	Day	41% 6% 11% 20% 19% 3	2254
	21st to end	Day	41% 6% 11% 22% 17% 4	2367
May	1st to 10th	Day	50% 8% 14% 15% 11% 2	4120
	11th to 20th	Day	46% 7% 15% 19% 10% 2	4270
	21st to end	Day	34% 8% 12% 26% 18% 2	4837
June	1st to 10th	Day	40% 8% 12% 25% 14% 1	2660
	11th to 20th	Day	37% 8% 15% 25% 13% 1	2660
	21st to end	Day	35% 9% 16% 24% 15% 1	2660
July	1st to 10th	Day	41% 11% 12% 19% 16% 1	4370
	11th to 20th	Day	37% 7% 17% 23% 13% 2	4365
	21st to end	Day	45% 8% 12% 18% 16% 2	4661
August	1st to 10th	Day	44% 7% 16% 23% 9%	4229
	11th to 20th	Day	34% 6% 15% 32% 12% 1	3766
	21st to end	Day	30% 8% 13% 29% 19% 2	4180
September	1st to 10th	Day	36% 7% 14% 22% 20% 2	2280
	11th to 20th	Day	31% 6% 11% 24% 26% 2	2156
	21st to end	Day	42% 6% 10% 21% 18% 3	2090
October	1st to 10th	Day	34% 6% 10% 22% 23% 5%	3416
	11th to 20th	Day	27% 3 11% 25% 31% 4	3126
	21st to end	Day	30% 4 14% 26% 22% 3	3081
November	1st to 10th	Day	36% 4 14% 21% 22% 2	1761
	11th to 20th	Day	37% 4 10% 22% 23% 3	1800
	21st to end	Day	39% 3 15% 27% 13% 3	1747
December	1st to 10th	Day	45% 4 15% 18% 15% 1	1520
	11th to 20th	Day	42% 3 15% 20% 19% 2	1906
	21st to end	Day	50% 6% 11% 22% 9% 1	2772
January	1st to 10th	Night	40% 4 12% 29% 12% 4	4429
	11th to 20th	Night	44% 4 12% 24% 13% 3	4440
	21st to end	Night	54% 4 9% 21% 11% 2	4774
February	1st to 10th	Night	45% 4 12% 23% 13% 2	2408
	11th to 20th	Night	43% 4 10% 20% 18% 5%	2220
	21st to end	Night	44% 4 8% 23% 16% 4	1884
March	1st to 10th	Night	52% 4 9% 20% 12% 2	3734
	11th to 20th	Night	38% 6% 14% 23% 15% 3	3690
	21st to end	Night	46% 4 7% 13% 24% 6%	3466
April	1st to 10th	Night	46% 4 10% 19% 16% 3	1900
	11th to 20th	Night	44% 4 10% 20% 21% 1	1875
	21st to end	Night	44% 5% 9% 20% 17% 5%	1811
May	1st to 10th	Night	54% 7% 12% 15% 10% 1	2840
	11th to 20th	Night	53% 8% 14% 14% 10% 1	2656
	21st to end	Night	42% 7% 14% 23% 13% 2	2739
June	1st to 10th	Night	44% 6% 10% 20% 18% 2	1520
	11th to 20th	Night	39% 7% 14% 28% 12% 1	1520
	21st to end	Night	38% 8% 13% 26% 14% 1	1520
July	1st to 10th	Night	45% 9% 14% 20% 12% 1	2480
	11th to 20th	Night	43% 8% 16% 23% 10% 1	2472
	21st to end	Night	49% 6% 14% 15% 14% 2	2651
August	1st to 10th	Night	51% 7% 15% 16% 9% 1	2640
	11th to 20th	Night	42% 7% 13% 29% 9% 1	3127
	21st to end	Night	28% 6% 13% 33% 20% 1	3476
September	1st to 10th	Night	40% 6% 10% 26% 18% 2	1900
	11th to 20th	Night	33% 4 11% 25% 24% 3	2023
	21st to end	Night	43% 6% 9% 20% 20% 3	2090
October	1st to 10th	Night	40% 5% 11% 23% 19% 2	3541
	11th to 20th	Night	25% 3 10% 26% 31% 4	3779
	21st to end	Night	32% 4 13% 27% 21% 2	4467
November	1st to 10th	Night	37% 4 12% 23% 20% 4	2537
	11th to 20th	Night	40% 3 9% 23% 20% 4	2600
	21st to end	Night	39% 5% 12% 30% 13% 2	2585
December	1st to 10th	Night	46% 4 13% 21% 14% 1	2660
	11th to 20th	Night	44% 4 13% 19% 18% 2	3288
	21st to end	Night	48% 5% 11% 23% 12% 1	4884

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	19% 13% 34% 24% 8% 1	180
	11th to 20th	Day	15% 17% 42% 21% 4 1	180
	21st to end	Day	21% 6% 37% 24% 9% 2	231
February	1st to 10th	Day	23% 10% 38% 22% 7%	331
	11th to 20th	Day	19% 11% 43% 25% 3	456
	21st to end	Day	23% 13% 36% 23% 6% 1	382
March	1st to 10th	Day	17% 10% 38% 28% 6%	460
	11th to 20th	Day	15% 7% 45% 25% 7% 1	460
	21st to end	Day	22% 8% 39% 25% 7% 1	506
April	1st to 10th	Day	22% 8% 34% 23% 10% 2	460
	11th to 20th	Day	19% 10% 33% 27% 10% 1	452
	21st to end	Day	25% 8% 25% 32% 9% 2	460
May	1st to 10th	Day	28% 5% 27% 29% 9% 3	463
	11th to 20th	Day	19% 5% 25% 33% 16% 1	487
	21st to end	Day	17% 3 16% 33% 23% 7%	529
June	1st to 10th	Day	18% 2 18% 35% 21% 6%	490
	11th to 20th	Day	14% 3 17% 36% 24% 5%	490
	21st to end	Day	12% 4 16% 35% 25% 7%	490
July	1st to 10th	Day	14% 3 11% 32% 31% 10%	485
	11th to 20th	Day	11% 4 8% 31% 36% 9%	484
	21st to end	Day	12% 3 14% 38% 28% 4	532
August	1st to 10th	Day	11% 3 10% 38% 29% 9%	486
	11th to 20th	Day	14% 2 9% 35% 30% 10%	479
	21st to end	Day	11% 2 13% 36% 28% 9%	539
September	1st to 10th	Day	17% 2 17% 28% 25% 10%	490
	11th to 20th	Day	14% 4 19% 27% 25% 12%	490
	21st to end	Day	20% 5% 21% 29% 20% 5%	490
October	1st to 10th	Day	24% 5% 18% 26% 19% 7%	490
	11th to 20th	Day	15% 7% 27% 30% 17% 3	488
	21st to end	Day	24% 7% 27% 27% 13% 2	429
November	1st to 10th	Day	13% 8% 26% 33% 16% 3	395
	11th to 20th	Day	19% 10% 37% 26% 9%	400
	21st to end	Day	19% 11% 32% 27% 11% 1	365
December	1st to 10th	Day	19% 9% 36% 27% 7% 2	180
	11th to 20th	Day	26% 11% 34% 24% 6%	180
	21st to end	Day	23% 6% 39% 21% 9% 3	198
January	1st to 10th	Night	19% 14% 38% 23% 5%	760
	11th to 20th	Night	25% 12% 37% 23% 4	760
	21st to end	Night	20% 13% 39% 25% 3	836
February	1st to 10th	Night	21% 11% 38% 27% 3	760
	11th to 20th	Night	22% 9% 44% 22% 2	743
	21st to end	Night	25% 10% 39% 21% 6%	628
March	1st to 10th	Night	22% 9% 37% 25% 7%	760
	11th to 20th	Night	20% 9% 37% 27% 6% 1	760
	21st to end	Night	22% 7% 38% 26% 7% 1	836
April	1st to 10th	Night	22% 7% 33% 31% 7% 1	760
	11th to 20th	Night	22% 5% 32% 30% 10%	751
	21st to end	Night	21% 4 31% 32% 9% 1	671
May	1st to 10th	Night	26% 6% 26% 27% 14% 1	570
	11th to 20th	Night	22% 5% 29% 32% 11% 1	469
	21st to end	Night	21% 2 15% 35% 25% 2	411
June	1st to 10th	Night	20% 4 20% 33% 21% 2	380
	11th to 20th	Night	18% 3 13% 43% 22% 1	380
	21st to end	Night	12% 2 16% 47% 22% 1	380
July	1st to 10th	Night	13% 4 15% 35% 30% 3	370
	11th to 20th	Night	12% 4 11% 42% 29% 3	368
	21st to end	Night	15% 2 15% 44% 23% 2	416
August	1st to 10th	Night	11% 2 15% 42% 29% 2	457
	11th to 20th	Night	14% 3 12% 38% 28% 5%	750
	21st to end	Night	13% 3 15% 34% 30% 6%	836
September	1st to 10th	Night	16% 2 22% 32% 23% 5%	760
	11th to 20th	Night	16% 4 18% 34% 21% 7%	760
	21st to end	Night	20% 4 22% 32% 19% 3	760
October	1st to 10th	Night	23% 7% 27% 24% 17% 4	760
	11th to 20th	Night	17% 9% 29% 32% 11% 1	760
	21st to end	Night	25% 9% 32% 24% 9% 1	836
November	1st to 10th	Night	15% 8% 32% 29% 13% 2	780
	11th to 20th	Night	22% 11% 35% 23% 8% 1	800
	21st to end	Night	18% 15% 34% 25% 7% 1	789
December	1st to 10th	Night	25% 12% 34% 23% 6% 1	760
	11th to 20th	Night	23% 13% 35% 25% 4	760
	21st to end	Night	24% 13% 36% 23% 3	836

Page generated at 2024-11-25 00:22:20. Version ac07

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