Big Lazer Creek WMA
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Big Lazer Creek WMA clear sky chart from 2005-11-06 to 2025-03-12.

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% 6% 2 6% 4 5% 5% 4 6% 8% 42%	109258
	Night	12% 6% 2 6% 4 4 4 4 6% 7% 45%	109766
Transparency	Day	38% 7% 11% 19% 19% 7%	113100
	Night	36% 6% 10% 19% 21% 8%	114062
Seeing	Day	15% 10% 23% 25% 19% 9%	15299
	Night	14% 8% 23% 30% 21% 4	25415

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% 7% 2 5% 3 3 3 2 4 5% 53%	4056
	11th to 20th	Day	12% 8% 2 4 2 2 3 3 5% 6% 53%	4060
	21st to end	Day	21% 6% 2 7% 4 3 3 3 5% 7% 39%	4787
February	1st to 10th	Day	14% 8% 3 6% 4 5% 5% 4 6% 6% 39%	2000
	11th to 20th	Day	20% 7% 2 5% 3 3 4 3 5% 6% 43%	1948
	21st to end	Day	14% 8% 2 7% 4 5% 5% 3 5% 8% 38%	1650
March	1st to 10th	Day	20% 10% 3 6% 4 3 3 4 6% 5% 35%	3318
	11th to 20th	Day	11% 5% 2 6% 4 4 5% 4 6% 8% 46%	3491
	21st to end	Day	17% 5% 2 7% 4 4 4 3 5% 7% 42%	3815
April	1st to 10th	Day	11% 6% 3 6% 4 4 4 4 5% 7% 46%	2133
	11th to 20th	Day	12% 5% 2 5% 3 4 4 3 4 8% 50%	2254
	21st to end	Day	7% 5% 2 4 4 4 5% 3 6% 7% 53%	2394
May	1st to 10th	Day	8% 5% 2 7% 5% 5% 5% 4 6% 9% 46%	4082
	11th to 20th	Day	16% 8% 2 7% 5% 5% 5% 4 6% 6% 37%	4081
	21st to end	Day	6% 4 2 6% 5% 5% 5% 4 7% 9% 47%	4476
June	1st to 10th	Day	10% 6% 3 7% 7% 6% 6% 5% 9% 10% 31%	2470
	11th to 20th	Day	5% 5% 2 6% 6% 6% 8% 6% 8% 11% 39%	2470
	21st to end	Day	6% 5% 3 7% 6% 7% 7% 6% 9% 10% 35%	2470
July	1st to 10th	Day	12% 7% 3 8% 7% 7% 8% 7% 9% 11% 21%	4120
	11th to 20th	Day	6% 4 2 8% 7% 7% 7% 5% 8% 12% 31%	4120
	21st to end	Day	7% 8% 3 10% 8% 8% 8% 7% 10% 13% 19%	4466
August	1st to 10th	Day	8% 6% 2 6% 6% 7% 7% 5% 8% 11% 34%	4052
	11th to 20th	Day	6% 4 2 5% 5% 5% 6% 4 7% 9% 47%	3729
	21st to end	Day	8% 4 1 5% 4 4 5% 5% 7% 9% 47%	4180
September	1st to 10th	Day	11% 7% 3 7% 6% 6% 5% 4 7% 8% 37%	2090
	11th to 20th	Day	15% 6% 2 6% 4 5% 5% 4 7% 8% 39%	2090
	21st to end	Day	13% 5% 2 7% 4 5% 4 3 5% 6% 46%	2090
October	1st to 10th	Day	12% 5% 2 4 4 4 4 4 4 6% 52%	2090
	11th to 20th	Day	11% 4 2 4 3 3 3 3 5% 6% 58%	2009
	21st to end	Day	11% 4 2 5% 3 4 4 2 4 4 56%	2090
November	1st to 10th	Day	12% 6% 2 5% 3 4 3 3 4 4 52%	1808
	11th to 20th	Day	13% 4 2 3 4 3 3 3 3 6% 56%	1800
	21st to end	Day	13% 5% 2 6% 4 4 4 3 5% 7% 47%	1800
December	1st to 10th	Day	15% 7% 2 4 3 3 3 3 5% 5% 50%	2930
	11th to 20th	Day	14% 9% 3 5% 3 3 4 3 4 5% 46%	3373
	21st to end	Day	20% 8% 3 5% 3 3 3 2 4 6% 42%	4466
January	1st to 10th	Night	14% 7% 2 5% 3 4 4 3 4 5% 50%	5889
	11th to 20th	Night	12% 6% 3 7% 5% 4 4 3 5% 6% 46%	5900
	21st to end	Night	18% 9% 2 5% 4 3 3 3 5% 6% 42%	6153
February	1st to 10th	Night	14% 7% 3 6% 4 4 4 3 5% 5% 45%	2400
	11th to 20th	Night	20% 9% 2 4 3 3 4 3 4 5% 44%	2338
	21st to end	Night	14% 7% 2 6% 4 3 4 3 6% 6% 44%	1980
March	1st to 10th	Night	23% 9% 3 7% 4 3 3 2 4 6% 36%	3754
	11th to 20th	Night	11% 6% 2 5% 4 4 4 3 6% 7% 48%	3498
	21st to end	Night	16% 6% 2 6% 4 4 4 3 5% 6% 44%	3817
April	1st to 10th	Night	10% 6% 2 5% 4 4 4 5% 6% 7% 47%	2062
	11th to 20th	Night	13% 4 1 5% 3 3 4 3 6% 8% 50%	1875
	21st to end	Night	7% 4 2 5% 3 4 4 4 5% 7% 55%	1783
May	1st to 10th	Night	5% 4 2 7% 5% 4 4 4 8% 11% 45%	2813
	11th to 20th	Night	14% 7% 2 6% 5% 4 4 4 5% 7% 41%	2812
	21st to end	Night	6% 4 2 4 3 4 4 4 6% 11% 51%	3079
June	1st to 10th	Night	8% 5% 3 6% 5% 5% 7% 5% 7% 11% 37%	1710
	11th to 20th	Night	3 4 1 5% 5% 5% 5% 5% 8% 12% 47%	1710
	21st to end	Night	5% 5% 1 6% 6% 6% 7% 5% 10% 13% 36%	1710
July	1st to 10th	Night	11% 7% 3 8% 7% 6% 7% 7% 8% 10% 25%	2840
	11th to 20th	Night	5% 4 3 7% 7% 6% 8% 6% 9% 14% 31%	2840
	21st to end	Night	8% 7% 4 9% 6% 7% 9% 7% 9% 11% 24%	3087
August	1st to 10th	Night	8% 6% 3 8% 6% 6% 7% 6% 9% 12% 30%	2873
	11th to 20th	Night	5% 4 2 5% 4 5% 6% 4 7% 11% 46%	3100
	21st to end	Night	8% 4 2 5% 4 3 4 4 7% 9% 52%	3476
September	1st to 10th	Night	9% 6% 2 6% 5% 5% 5% 5% 7% 9% 40%	2071
	11th to 20th	Night	12% 6% 2 6% 5% 5% 4 4 6% 7% 41%	2090
	21st to end	Night	10% 7% 3 6% 4 5% 4 3 6% 7% 46%	2090
October	1st to 10th	Night	12% 5% 1 6% 3 3 3 3 3 6% 54%	2090
	11th to 20th	Night	10% 5% 2 4 3 4 3 3 4 5% 59%	2168
	21st to end	Night	11% 4 1 5% 3 3 3 3 4 5% 58%	2508
November	1st to 10th	Night	12% 6% 2 4 3 3 3 4 5% 5% 55%	2488
	11th to 20th	Night	13% 6% 2 5% 3 3 3 2 4 5% 54%	2600
	21st to end	Night	13% 6% 2 6% 5% 3 3 3 4 7% 49%	2600
December	1st to 10th	Night	13% 6% 3 5% 3 3 3 2 4 5% 53%	4250
	11th to 20th	Night	15% 5% 2 5% 3 3 4 3 5% 6% 49%	4822
	21st to end	Night	20% 7% 3 6% 4 3 4 3 4 6% 41%	6490

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	36% 4 3 19% 31% 8%	4057
	11th to 20th	Day	32% 3 3 18% 32% 11%	4060
	21st to end	Day	46% 3 7% 13% 21% 10%	4787
February	1st to 10th	Day	44% 6% 8% 17% 19% 8%	2000
	11th to 20th	Day	42% 5% 5% 17% 23% 7%	1958
	21st to end	Day	43% 5% 7% 16% 20% 10%	1650
March	1st to 10th	Day	48% 7% 9% 13% 17% 7%	3318
	11th to 20th	Day	35% 7% 8% 16% 22% 12%	3491
	21st to end	Day	41% 6% 10% 18% 16% 9%	3815
April	1st to 10th	Day	36% 6% 10% 20% 18% 9%	2133
	11th to 20th	Day	33% 5% 9% 19% 24% 10%	2254
	21st to end	Day	29% 6% 10% 23% 26% 6%	2394
May	1st to 10th	Day	33% 8% 13% 22% 20% 3	4120
	11th to 20th	Day	42% 9% 12% 22% 14% 2	4085
	21st to end	Day	30% 8% 15% 25% 19% 2	4489
June	1st to 10th	Day	44% 10% 15% 18% 11% 2	2470
	11th to 20th	Day	33% 11% 16% 25% 15% 1	2470
	21st to end	Day	37% 13% 18% 18% 11% 3	2470
July	1st to 10th	Day	50% 10% 23% 12% 4 1	4055
	11th to 20th	Day	42% 11% 21% 21% 4 1	4051
	21st to end	Day	52% 13% 20% 11% 4	4324
August	1st to 10th	Day	39% 9% 16% 27% 8%	4039
	11th to 20th	Day	31% 8% 14% 30% 16% 1	3765
	21st to end	Day	31% 7% 16% 29% 14% 2	4179
September	1st to 10th	Day	42% 9% 15% 14% 14% 5%	2090
	11th to 20th	Day	41% 8% 11% 19% 17% 4	2090
	21st to end	Day	38% 6% 8% 22% 20% 6%	2090
October	1st to 10th	Day	30% 4 7% 13% 29% 17%	3480
	11th to 20th	Day	17% 3 4 18% 25% 34%	3314
	21st to end	Day	23% 3 4 16% 39% 15%	3428
November	1st to 10th	Day	35% 4 6% 14% 25% 15%	1808
	11th to 20th	Day	31% 4 6% 18% 25% 16%	1800
	21st to end	Day	36% 5% 8% 18% 23% 10%	1800
December	1st to 10th	Day	37% 4 6% 18% 26% 9%	2930
	11th to 20th	Day	42% 2 8% 18% 22% 8%	3370
	21st to end	Day	43% 4 6% 21% 23% 3	4466
January	1st to 10th	Night	35% 5% 4 19% 29% 8%	5889
	11th to 20th	Night	39% 4 5% 18% 25% 9%	5900
	21st to end	Night	43% 3 5% 15% 26% 8%	6153
February	1st to 10th	Night	41% 4 6% 18% 20% 11%	2400
	11th to 20th	Night	43% 4 6% 14% 22% 11%	2339
	21st to end	Night	40% 6% 9% 14% 17% 14%	1980
March	1st to 10th	Night	49% 6% 8% 15% 14% 8%	3754
	11th to 20th	Night	34% 6% 10% 13% 26% 12%	3498
	21st to end	Night	40% 6% 7% 17% 20% 10%	3817
April	1st to 10th	Night	34% 7% 10% 18% 19% 11%	2062
	11th to 20th	Night	32% 5% 8% 22% 23% 12%	1875
	21st to end	Night	28% 6% 11% 23% 24% 8%	1783
May	1st to 10th	Night	27% 12% 15% 23% 19% 4	2840
	11th to 20th	Night	39% 10% 14% 23% 12% 2	2813
	21st to end	Night	24% 8% 16% 29% 19% 3	3087
June	1st to 10th	Night	38% 12% 17% 19% 13% 1	1710
	11th to 20th	Night	26% 10% 23% 27% 12% 2	1710
	21st to end	Night	35% 11% 21% 17% 12% 4	1710
July	1st to 10th	Night	49% 12% 22% 11% 4 1	2795
	11th to 20th	Night	40% 12% 26% 16% 6% 1	2786
	21st to end	Night	49% 14% 20% 12% 4 1	2988
August	1st to 10th	Night	42% 8% 18% 24% 7%	2862
	11th to 20th	Night	29% 9% 16% 30% 15% 1	3130
	21st to end	Night	28% 7% 17% 29% 16% 2	3476
September	1st to 10th	Night	37% 11% 17% 18% 14% 4	2071
	11th to 20th	Night	39% 9% 11% 18% 17% 5%	2090
	21st to end	Night	36% 8% 11% 17% 21% 8%	2090
October	1st to 10th	Night	35% 3 8% 14% 25% 15%	3480
	11th to 20th	Night	17% 2 4 14% 29% 34%	3602
	21st to end	Night	20% 3 4 20% 34% 19%	4120
November	1st to 10th	Night	32% 4 9% 15% 27% 14%	2488
	11th to 20th	Night	33% 3 5% 16% 27% 15%	2600
	21st to end	Night	37% 4 7% 17% 24% 11%	2600
December	1st to 10th	Night	34% 3 6% 20% 28% 9%	4250
	11th to 20th	Night	37% 3 11% 18% 24% 8%	4824
	21st to end	Night	44% 4 5% 21% 23% 3	6490

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	21% 25% 43% 9% 2	300
	11th to 20th	Day	21% 25% 32% 14% 6% 2	300
	21st to end	Day	24% 25% 37% 10% 3	330
February	1st to 10th	Day	17% 25% 39% 17% 3	300
	11th to 20th	Day	33% 21% 32% 12% 2	300
	21st to end	Day	19% 25% 43% 11% 2	249
March	1st to 10th	Day	20% 24% 30% 20% 5% 1	359
	11th to 20th	Day	17% 19% 37% 18% 9% 1	464
	21st to end	Day	18% 20% 33% 22% 7%	506
April	1st to 10th	Day	19% 17% 32% 21% 10% 1	460
	11th to 20th	Day	13% 17% 32% 23% 12% 3	452
	21st to end	Day	13% 11% 30% 28% 16% 3	460
May	1st to 10th	Day	10% 14% 26% 29% 16% 5%	463
	11th to 20th	Day	12% 5% 25% 30% 17% 10%	487
	21st to end	Day	13% 5% 17% 30% 24% 11%	529
June	1st to 10th	Day	11% 2 19% 32% 25% 11%	490
	11th to 20th	Day	6% 4 15% 28% 28% 19%	490
	21st to end	Day	7% 3 15% 32% 27% 16%	490
July	1st to 10th	Day	9% 2 9% 26% 32% 22%	485
	11th to 20th	Day	5% 2 9% 23% 34% 27%	484
	21st to end	Day	7% 2 7% 26% 38% 20%	532
August	1st to 10th	Day	10% 2 11% 26% 31% 20%	486
	11th to 20th	Day	9% 1 9% 24% 36% 20%	479
	21st to end	Day	13% 3 10% 29% 30% 14%	539
September	1st to 10th	Day	13% 2 12% 27% 31% 14%	490
	11th to 20th	Day	17% 2 14% 30% 28% 9%	490
	21st to end	Day	14% 3 15% 29% 28% 11%	490
October	1st to 10th	Day	15% 5% 24% 30% 17% 8%	490
	11th to 20th	Day	12% 9% 22% 33% 18% 6%	490
	21st to end	Day	12% 11% 25% 30% 18% 4	539
November	1st to 10th	Day	21% 8% 26% 29% 12% 3	346
	11th to 20th	Day	15% 16% 37% 23% 7% 1	300
	21st to end	Day	15% 16% 36% 23% 10% 1	300
December	1st to 10th	Day	21% 21% 35% 18% 4 1	300
	11th to 20th	Day	24% 19% 36% 16% 5%	300
	21st to end	Day	30% 16% 27% 22% 4 1	330
January	1st to 10th	Night	21% 18% 35% 22% 5%	800
	11th to 20th	Night	20% 15% 30% 27% 9%	800
	21st to end	Night	20% 14% 37% 25% 3	880
February	1st to 10th	Night	18% 13% 33% 29% 7%	800
	11th to 20th	Night	24% 15% 30% 27% 4	783
	21st to end	Night	17% 17% 36% 27% 3	660
March	1st to 10th	Night	15% 14% 36% 30% 5%	800
	11th to 20th	Night	16% 12% 33% 27% 11%	767
	21st to end	Night	16% 14% 30% 30% 10% 1	836
April	1st to 10th	Night	13% 12% 33% 31% 12%	732
	11th to 20th	Night	15% 11% 26% 33% 14% 1	563
	21st to end	Night	7% 9% 25% 37% 21% 1	570
May	1st to 10th	Night	7% 9% 25% 33% 24% 2	570
	11th to 20th	Night	10% 3 22% 36% 23% 6%	561
	21st to end	Night	11% 3 15% 35% 32% 5%	617
June	1st to 10th	Night	11% 2 12% 39% 33% 5%	570
	11th to 20th	Night	4 2 13% 32% 35% 15%	570
	21st to end	Night	5% 2 10% 33% 40% 9%	570
July	1st to 10th	Night	8% 2 5% 28% 40% 16%	555
	11th to 20th	Night	7% 1 6% 24% 45% 18%	552
	21st to end	Night	7% 1 7% 26% 48% 11%	624
August	1st to 10th	Night	6% 2 7% 28% 41% 16%	567
	11th to 20th	Night	8% 1 6% 28% 45% 10%	564
	21st to end	Night	13% 2 10% 27% 36% 12%	627
September	1st to 10th	Night	11% 2 12% 26% 39% 10%	741
	11th to 20th	Night	13% 3 14% 32% 33% 5%	760
	21st to end	Night	12% 3 15% 34% 32% 4	760
October	1st to 10th	Night	15% 2 21% 33% 23% 5%	760
	11th to 20th	Night	13% 6% 26% 29% 25% 2	760
	21st to end	Night	13% 7% 24% 33% 21% 2	836
November	1st to 10th	Night	14% 7% 23% 34% 20% 1	780
	11th to 20th	Night	16% 10% 29% 30% 14% 1	800
	21st to end	Night	13% 12% 29% 31% 13% 1	800
December	1st to 10th	Night	16% 12% 34% 26% 12% 1	800
	11th to 20th	Night	19% 10% 32% 28% 10% 2	800
	21st to end	Night	25% 12% 27% 28% 6%	880

Page generated at 2025-03-09 08:08:45. Version ac07

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