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 2026-07-16.

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% 5% 5% 5% 4 6% 8% 41%	137931
	Night	12% 6% 2 6% 4 4 4 4 6% 7% 44%	134765
Transparency	Day	39% 6% 12% 19% 18% 7%	141729
	Night	38% 6% 11% 19% 19% 8%	139038
Seeing	Day	15% 10% 23% 25% 18% 8%	17138
	Night	14% 8% 23% 30% 20% 4	27133

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	14% 7% 3 7% 4 3 3 3 4 5% 47%	5258
	11th to 20th	Day	11% 7% 2 4 2 2 2 2 5% 6% 56%	5280
	21st to end	Day	20% 7% 3 8% 4 4 4 3 4 6% 37%	6196
February	1st to 10th	Day	13% 8% 3 6% 4 5% 5% 4 6% 6% 40%	2100
	11th to 20th	Day	19% 7% 2 5% 3 3 4 3 5% 6% 42%	2048
	21st to end	Day	14% 8% 2 8% 4 4 5% 3 5% 8% 39%	1730
March	1st to 10th	Day	19% 9% 3 6% 4 4 4 4 6% 5% 37%	4720
	11th to 20th	Day	9% 5% 2 5% 4 4 4 4 5% 7% 52%	5090
	21st to end	Day	16% 6% 3 7% 3 4 4 3 5% 6% 45%	5586
April	1st to 10th	Day	11% 6% 2 6% 4 4 4 4 6% 7% 46%	2357
	11th to 20th	Day	11% 5% 2 5% 3 4 4 3 4 7% 52%	2494
	21st to end	Day	7% 5% 2 5% 5% 4 6% 3 6% 7% 51%	2646
May	1st to 10th	Day	13% 7% 2 7% 5% 5% 5% 4 6% 8% 37%	7616
	11th to 20th	Day	13% 6% 2 6% 5% 5% 5% 5% 8% 9% 36%	7626
	21st to end	Day	10% 7% 3 8% 6% 5% 6% 5% 7% 9% 35%	8391
June	1st to 10th	Day	10% 6% 3 8% 7% 6% 6% 5% 8% 10% 31%	2730
	11th to 20th	Day	5% 5% 2 6% 6% 6% 8% 6% 8% 11% 38%	2730
	21st to end	Day	5% 5% 2 6% 6% 7% 7% 6% 9% 10% 35%	2730
July	1st to 10th	Day	9% 6% 2 8% 6% 7% 8% 6% 9% 12% 26%	6030
	11th to 20th	Day	5% 4 2 7% 6% 6% 7% 5% 9% 13% 36%	5965
	21st to end	Day	7% 7% 3 9% 7% 8% 8% 7% 10% 13% 24%	6424
August	1st to 10th	Day	9% 6% 2 6% 6% 7% 7% 5% 8% 11% 34%	4180
	11th to 20th	Day	6% 4 2 6% 5% 5% 6% 4 7% 9% 47%	3849
	21st to end	Day	8% 4 1 5% 4 5% 5% 5% 7% 9% 47%	4312
September	1st to 10th	Day	10% 7% 3 7% 5% 6% 5% 4 7% 9% 38%	2200
	11th to 20th	Day	14% 6% 2 6% 4 5% 5% 4 7% 8% 40%	2200
	21st to end	Day	12% 5% 2 7% 4 5% 5% 3 5% 6% 46%	2200
October	1st to 10th	Day	12% 5% 2 5% 4 4 4 4 4 6% 51%	2200
	11th to 20th	Day	11% 4 2 4 3 3 3 2 4 6% 59%	2115
	21st to end	Day	12% 4 2 5% 3 4 4 2 4 5% 56%	2200
November	1st to 10th	Day	12% 6% 2 5% 3 4 3 3 4 4 53%	1900
	11th to 20th	Day	13% 4 2 3 3 3 3 2 3 6% 57%	1890
	21st to end	Day	13% 5% 2 6% 4 4 4 4 5% 7% 48%	1890
December	1st to 10th	Day	16% 7% 2 4 3 3 3 3 5% 5% 49%	3020
	11th to 20th	Day	14% 9% 3 5% 3 3 4 3 4 5% 46%	3463
	21st to end	Day	20% 8% 2 5% 3 3 3 2 4 6% 43%	4565
January	1st to 10th	Night	13% 8% 2 6% 4 5% 4 3 5% 5% 46%	7635
	11th to 20th	Night	13% 7% 3 6% 4 4 3 3 4 5% 48%	7680
	21st to end	Night	19% 10% 3 6% 4 3 3 3 4 6% 39%	7969
February	1st to 10th	Night	14% 7% 2 6% 4 4 4 3 5% 5% 46%	2520
	11th to 20th	Night	19% 9% 2 5% 3 3 3 3 4 5% 44%	2458
	21st to end	Night	15% 7% 2 6% 4 3 4 3 6% 6% 43%	2076
March	1st to 10th	Night	19% 8% 3 7% 4 3 4 3 4 6% 38%	5352
	11th to 20th	Night	10% 5% 2 5% 4 4 4 3 5% 7% 51%	5090
	21st to end	Night	13% 5% 2 6% 4 4 4 3 5% 5% 48%	5588
April	1st to 10th	Night	10% 6% 2 6% 4 4 4 5% 6% 7% 46%	2279
	11th to 20th	Night	12% 4 1 5% 3 3 4 3 5% 7% 53%	2075
	21st to end	Night	7% 4 2 6% 3 4 5% 4 5% 7% 53%	1971
May	1st to 10th	Night	13% 6% 2 7% 5% 4 4 4 7% 10% 40%	5237
	11th to 20th	Night	13% 5% 2 6% 4 5% 5% 5% 7% 9% 39%	5234
	21st to end	Night	12% 7% 3 7% 4 5% 5% 5% 6% 10% 36%	5761
June	1st to 10th	Night	8% 5% 2 6% 5% 5% 7% 5% 8% 11% 37%	1890
	11th to 20th	Night	5% 5% 1 5% 5% 4 5% 5% 8% 12% 45%	1890
	21st to end	Night	5% 5% 2 7% 5% 6% 6% 5% 9% 13% 38%	1890
July	1st to 10th	Night	10% 7% 3 8% 7% 6% 7% 7% 8% 11% 27%	4148
	11th to 20th	Night	4 4 2 7% 6% 6% 7% 6% 9% 15% 35%	4102
	21st to end	Night	7% 6% 3 9% 6% 7% 8% 6% 9% 12% 26%	4427
August	1st to 10th	Night	9% 6% 3 8% 6% 6% 6% 6% 9% 12% 30%	2964
	11th to 20th	Night	5% 4 2 5% 4 5% 6% 4 7% 11% 46%	3200
	21st to end	Night	8% 4 2 5% 4 3 4 4 7% 9% 51%	3586
September	1st to 10th	Night	9% 6% 2 6% 5% 5% 5% 5% 7% 10% 40%	2180
	11th to 20th	Night	12% 6% 2 6% 5% 5% 4 4 6% 7% 42%	2200
	21st to end	Night	10% 7% 3 6% 4 5% 4 3 6% 7% 45%	2200
October	1st to 10th	Night	12% 5% 2 6% 3 3 3 3 4 7% 53%	2200
	11th to 20th	Night	10% 5% 2 4 3 4 3 3 4 5% 60%	2282
	21st to end	Night	12% 4 1 5% 3 3 3 3 4 5% 57%	2640
November	1st to 10th	Night	12% 6% 1 4 3 3 4 4 5% 4 55%	2616
	11th to 20th	Night	13% 5% 2 4 3 2 3 2 4 5% 56%	2730
	21st to end	Night	12% 6% 2 6% 5% 3 3 3 4 7% 49%	2730
December	1st to 10th	Night	13% 7% 3 5% 3 3 3 2 4 5% 53%	4380
	11th to 20th	Night	14% 5% 2 5% 3 3 4 3 5% 6% 49%	4952
	21st to end	Night	19% 7% 3 6% 4 3 4 3 4 6% 42%	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	41% 3 6% 20% 25% 6%	5259
	11th to 20th	Day	30% 3 4 17% 33% 14%	5280
	21st to end	Day	50% 3 6% 12% 20% 10%	6196
February	1st to 10th	Day	43% 5% 7% 16% 20% 8%	2100
	11th to 20th	Day	43% 5% 5% 18% 23% 7%	2058
	21st to end	Day	43% 5% 7% 15% 20% 10%	1730
March	1st to 10th	Day	47% 5% 8% 12% 22% 7%	4720
	11th to 20th	Day	32% 5% 7% 14% 22% 21%	5090
	21st to end	Day	41% 4 8% 19% 18% 11%	5586
April	1st to 10th	Day	36% 6% 11% 21% 18% 9%	2357
	11th to 20th	Day	32% 4 8% 19% 26% 11%	2494
	21st to end	Day	31% 6% 11% 23% 24% 5%	2646
May	1st to 10th	Day	44% 5% 13% 19% 16% 3	7651
	11th to 20th	Day	42% 6% 18% 21% 11% 2	7630
	21st to end	Day	45% 8% 14% 16% 16% 1	8405
June	1st to 10th	Day	44% 9% 15% 18% 11% 2	2730
	11th to 20th	Day	35% 10% 17% 23% 14% 1	2730
	21st to end	Day	37% 12% 18% 19% 11% 3	2730
July	1st to 10th	Day	46% 9% 23% 18% 4 1	5965
	11th to 20th	Day	38% 9% 30% 20% 3	5896
	21st to end	Day	48% 10% 22% 17% 3	6240
August	1st to 10th	Day	40% 8% 16% 27% 8%	4167
	11th to 20th	Day	32% 8% 14% 30% 15% 1	3885
	21st to end	Day	32% 7% 16% 28% 14% 2	4311
September	1st to 10th	Day	41% 9% 15% 16% 15% 4	2200
	11th to 20th	Day	40% 7% 11% 20% 18% 4	2200
	21st to end	Day	38% 6% 9% 22% 20% 6%	2200
October	1st to 10th	Day	31% 4 7% 13% 29% 17%	3590
	11th to 20th	Day	17% 2 4 18% 26% 33%	3420
	21st to end	Day	23% 3 4 16% 39% 15%	3538
November	1st to 10th	Day	34% 4 6% 15% 26% 15%	1900
	11th to 20th	Day	30% 3 7% 19% 26% 15%	1890
	21st to end	Day	35% 5% 9% 18% 24% 10%	1890
December	1st to 10th	Day	38% 4 6% 18% 25% 9%	3020
	11th to 20th	Day	41% 2 8% 18% 22% 8%	3460
	21st to end	Day	43% 4 6% 21% 23% 3	4565
January	1st to 10th	Night	39% 4 7% 21% 23% 6%	7636
	11th to 20th	Night	39% 3 5% 17% 25% 10%	7680
	21st to end	Night	48% 2 4 15% 23% 8%	7969
February	1st to 10th	Night	40% 4 6% 18% 21% 11%	2520
	11th to 20th	Night	43% 4 6% 15% 22% 10%	2459
	21st to end	Night	40% 5% 9% 14% 17% 14%	2076
March	1st to 10th	Night	47% 5% 7% 15% 16% 11%	5352
	11th to 20th	Night	32% 5% 8% 12% 24% 18%	5090
	21st to end	Night	38% 4 6% 19% 21% 11%	5588
April	1st to 10th	Night	35% 6% 10% 19% 19% 11%	2279
	11th to 20th	Night	30% 4 7% 23% 24% 12%	2075
	21st to end	Night	30% 5% 11% 23% 23% 8%	1971
May	1st to 10th	Night	39% 7% 16% 18% 16% 4	5264
	11th to 20th	Night	39% 7% 17% 24% 12% 2	5235
	21st to end	Night	42% 7% 15% 21% 14% 1	5771
June	1st to 10th	Night	38% 11% 17% 19% 13% 2	1890
	11th to 20th	Night	29% 9% 23% 26% 11% 2	1890
	21st to end	Night	34% 10% 21% 19% 12% 3	1890
July	1st to 10th	Night	48% 10% 22% 16% 4 1	4105
	11th to 20th	Night	36% 11% 32% 17% 4 1	4051
	21st to end	Night	48% 11% 23% 15% 3	4297
August	1st to 10th	Night	43% 8% 18% 24% 7%	2953
	11th to 20th	Night	30% 9% 16% 30% 14% 1	3230
	21st to end	Night	29% 7% 17% 29% 16% 2	3586
September	1st to 10th	Night	36% 10% 17% 19% 14% 4	2180
	11th to 20th	Night	38% 9% 11% 20% 18% 5%	2200
	21st to end	Night	36% 7% 11% 17% 21% 8%	2200
October	1st to 10th	Night	35% 3 8% 14% 25% 15%	3590
	11th to 20th	Night	17% 2 4 14% 29% 34%	3716
	21st to end	Night	21% 3 4 20% 34% 19%	4252
November	1st to 10th	Night	31% 4 8% 15% 28% 13%	2616
	11th to 20th	Night	32% 3 5% 17% 28% 15%	2730
	21st to end	Night	37% 4 7% 17% 24% 11%	2730
December	1st to 10th	Night	35% 3 5% 20% 27% 9%	4380
	11th to 20th	Night	37% 3 11% 18% 24% 8%	4954
	21st to end	Night	44% 4 5% 22% 22% 3	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	21% 24% 43% 9% 3	330
	11th to 20th	Day	23% 25% 31% 13% 6% 2	330
	21st to end	Day	24% 25% 37% 11% 3	363
February	1st to 10th	Day	16% 26% 39% 16% 2	330
	11th to 20th	Day	33% 21% 33% 12% 2	330
	21st to end	Day	22% 25% 40% 11% 3	273
March	1st to 10th	Day	19% 22% 30% 22% 6% 1	392
	11th to 20th	Day	19% 18% 36% 18% 9% 1	540
	21st to end	Day	18% 19% 33% 23% 7%	594
April	1st to 10th	Day	19% 16% 31% 22% 11% 1	540
	11th to 20th	Day	12% 15% 31% 25% 12% 4	532
	21st to end	Day	13% 10% 30% 27% 17% 3	540
May	1st to 10th	Day	13% 13% 28% 28% 14% 5%	543
	11th to 20th	Day	13% 5% 27% 31% 16% 9%	567
	21st to end	Day	15% 6% 18% 29% 22% 10%	617
June	1st to 10th	Day	12% 2 20% 31% 24% 11%	570
	11th to 20th	Day	7% 4 16% 28% 27% 17%	570
	21st to end	Day	6% 3 14% 33% 27% 16%	570
July	1st to 10th	Day	8% 2 8% 27% 33% 22%	565
	11th to 20th	Day	6% 3 8% 23% 35% 25%	544
	21st to end	Day	6% 2 7% 27% 38% 20%	576
August	1st to 10th	Day	13% 2 10% 27% 29% 18%	526
	11th to 20th	Day	9% 1 8% 24% 36% 22%	519
	21st to end	Day	13% 3 11% 30% 28% 14%	583
September	1st to 10th	Day	13% 2 13% 28% 30% 14%	530
	11th to 20th	Day	15% 2 13% 32% 29% 9%	530
	21st to end	Day	14% 3 14% 30% 28% 10%	530
October	1st to 10th	Day	16% 5% 25% 30% 17% 7%	530
	11th to 20th	Day	11% 8% 22% 33% 20% 6%	530
	21st to end	Day	13% 10% 26% 29% 17% 4	583
November	1st to 10th	Day	21% 8% 26% 30% 12% 3	378
	11th to 20th	Day	14% 15% 39% 23% 8% 1	330
	21st to end	Day	15% 17% 35% 22% 9% 1	330
December	1st to 10th	Day	25% 19% 34% 17% 4 1	330
	11th to 20th	Day	23% 20% 33% 17% 6% 1	330
	21st to end	Day	29% 15% 28% 23% 4 1	363
January	1st to 10th	Night	21% 17% 35% 23% 5%	840
	11th to 20th	Night	20% 15% 30% 27% 8%	840
	21st to end	Night	20% 15% 37% 25% 3	924
February	1st to 10th	Night	18% 13% 33% 29% 7%	840
	11th to 20th	Night	24% 15% 31% 26% 4	823
	21st to end	Night	18% 17% 35% 26% 4	692
March	1st to 10th	Night	14% 13% 35% 31% 6%	840
	11th to 20th	Night	16% 13% 33% 28% 11%	840
	21st to end	Night	15% 14% 31% 30% 9% 1	924
April	1st to 10th	Night	12% 11% 33% 32% 12%	809
	11th to 20th	Night	14% 10% 26% 33% 16% 1	623
	21st to end	Night	9% 8% 25% 37% 20% 1	630
May	1st to 10th	Night	9% 8% 25% 33% 23% 2	630
	11th to 20th	Night	11% 4 21% 37% 22% 5%	621
	21st to end	Night	12% 3 15% 35% 31% 5%	683
June	1st to 10th	Night	11% 2 12% 37% 32% 5%	630
	11th to 20th	Night	6% 2 13% 32% 34% 14%	630
	21st to end	Night	5% 3 10% 31% 42% 9%	630
July	1st to 10th	Night	7% 2 5% 28% 41% 16%	615
	11th to 20th	Night	8% 1 6% 23% 46% 17%	597
	21st to end	Night	6% 1 7% 27% 48% 11%	657
August	1st to 10th	Night	9% 2 7% 28% 39% 15%	597
	11th to 20th	Night	9% 1 6% 28% 45% 11%	594
	21st to end	Night	14% 2 11% 27% 34% 12%	660
September	1st to 10th	Night	11% 2 12% 27% 38% 9%	780
	11th to 20th	Night	13% 3 14% 32% 34% 5%	800
	21st to end	Night	12% 3 14% 35% 31% 4	800
October	1st to 10th	Night	15% 2 22% 34% 23% 5%	800
	11th to 20th	Night	12% 6% 25% 30% 26% 2	800
	21st to end	Night	14% 7% 24% 33% 20% 2	880
November	1st to 10th	Night	15% 7% 23% 35% 20% 1	820
	11th to 20th	Night	15% 10% 29% 31% 14% 1	840
	21st to end	Night	13% 12% 29% 31% 13% 1	840
December	1st to 10th	Night	18% 12% 33% 26% 11% 1	840
	11th to 20th	Night	19% 10% 31% 28% 10% 1	840
	21st to end	Night	24% 12% 27% 29% 7% 1	924

Page generated at 2026-07-13 03:14:51. Version ac07

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