Weiser State Forest
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Weiser State Forest clear sky chart from 2005-11-06 to 2025-01-07.

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% 8% 3 7% 5% 4 4 4 5% 7% 37%	105003
	Night	16% 8% 3 7% 4 4 4 3 5% 7% 38%	104026
Transparency	Day	44% 6% 12% 23% 14% 2	108606
	Night	44% 6% 12% 22% 14% 2	108512
Seeing	Day	23% 14% 28% 21% 11% 4	15000
	Night	21% 13% 26% 28% 11% 1	24466

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	15% 12% 4 7% 5% 4 4 3 4 5% 38%	2565
	11th to 20th	Day	14% 14% 5% 14% 6% 5% 4 4 5% 6% 23%	2722
	21st to end	Day	20% 12% 5% 9% 6% 4 4 3 4 5% 27%	3124
February	1st to 10th	Day	16% 11% 3 7% 5% 6% 5% 4 5% 6% 32%	1710
	11th to 20th	Day	15% 9% 4 9% 5% 4 4 4 6% 7% 34%	1709
	21st to end	Day	18% 11% 5% 8% 4 4 4 3 4 6% 33%	1570
March	1st to 10th	Day	25% 8% 2 6% 4 4 4 3 4 6% 34%	3297
	11th to 20th	Day	10% 8% 3 8% 5% 5% 4 4 5% 7% 41%	3480
	21st to end	Day	20% 9% 3 6% 4 3 3 3 4 5% 42%	3928
April	1st to 10th	Day	16% 9% 3 8% 5% 5% 4 4 5% 6% 35%	2280
	11th to 20th	Day	16% 8% 2 7% 4 5% 4 4 5% 7% 39%	2254
	21st to end	Day	18% 5% 3 7% 5% 4 4 4 6% 7% 38%	2280
May	1st to 10th	Day	29% 7% 2 5% 5% 4 4 3 4 6% 31%	4130
	11th to 20th	Day	23% 8% 3 8% 6% 5% 5% 4 5% 7% 27%	4398
	21st to end	Day	13% 6% 2 5% 4 4 5% 4 6% 9% 42%	4837
June	1st to 10th	Day	13% 7% 2 6% 6% 5% 4 4 7% 8% 37%	2660
	11th to 20th	Day	13% 7% 3 7% 5% 4 5% 5% 7% 8% 37%	2660
	21st to end	Day	11% 5% 2 6% 4 5% 5% 5% 7% 10% 40%	2660
July	1st to 10th	Day	7% 5% 2 8% 6% 6% 7% 5% 7% 10% 36%	4440
	11th to 20th	Day	8% 6% 3 7% 5% 4 6% 5% 7% 11% 40%	4440
	21st to end	Day	12% 7% 3 7% 6% 5% 6% 4 6% 8% 36%	4561
August	1st to 10th	Day	17% 8% 2 6% 5% 5% 5% 5% 6% 9% 31%	4104
	11th to 20th	Day	14% 7% 2 6% 4 4 5% 4 7% 8% 39%	3892
	21st to end	Day	12% 6% 2 5% 3 3 4 3 5% 8% 47%	4180
September	1st to 10th	Day	16% 6% 2 5% 4 3 4 3 5% 7% 46%	2280
	11th to 20th	Day	13% 5% 2 4 4 3 4 3 6% 7% 50%	2280
	21st to end	Day	22% 8% 2 6% 3 4 3 4 4 6% 38%	2010
October	1st to 10th	Day	19% 6% 1 6% 3 4 4 4 5% 7% 41%	1900
	11th to 20th	Day	18% 6% 2 5% 4 4 3 3 6% 6% 42%	1900
	21st to end	Day	18% 7% 3 6% 4 3 4 4 5% 7% 39%	2090
November	1st to 10th	Day	13% 7% 2 5% 3 3 3 3 6% 7% 48%	1775
	11th to 20th	Day	17% 7% 2 6% 4 4 4 4 5% 6% 40%	1741
	21st to end	Day	17% 8% 3 6% 5% 4 6% 4 5% 6% 37%	1600
December	1st to 10th	Day	14% 8% 4 9% 4 6% 4 4 5% 6% 36%	2600
	11th to 20th	Day	21% 9% 3 7% 4 3 4 3 5% 6% 35%	2986
	21st to end	Day	16% 12% 4 11% 5% 5% 5% 3 6% 6% 26%	3960
January	1st to 10th	Night	15% 11% 3 8% 5% 5% 4 3 5% 7% 33%	4514
	11th to 20th	Night	17% 10% 5% 10% 5% 4 4 3 5% 5% 31%	4234
	21st to end	Night	23% 10% 3 9% 4 4 4 3 4 5% 30%	4532
February	1st to 10th	Night	16% 10% 3 7% 5% 4 5% 4 5% 6% 35%	2470
	11th to 20th	Night	15% 10% 3 7% 5% 5% 5% 5% 5% 6% 33%	2356
	21st to end	Night	17% 9% 4 7% 5% 5% 4 3 5% 6% 35%	1884
March	1st to 10th	Night	22% 12% 3 7% 4 3 4 3 3 4 35%	3542
	11th to 20th	Night	11% 9% 3 8% 4 4 4 4 4 5% 44%	3479
	21st to end	Night	16% 10% 3 6% 4 3 4 3 4 5% 44%	3702
April	1st to 10th	Night	17% 10% 3 7% 6% 4 4 4 6% 7% 33%	1900
	11th to 20th	Night	15% 7% 3 6% 5% 4 4 4 6% 8% 39%	1875
	21st to end	Night	18% 5% 3 6% 4 4 3 3 5% 7% 42%	1900
May	1st to 10th	Night	27% 8% 3 6% 5% 4 4 3 5% 6% 30%	2822
	11th to 20th	Night	25% 9% 4 7% 4 4 4 4 5% 6% 28%	2495
	21st to end	Night	12% 6% 2 7% 5% 4 4 3 6% 10% 41%	2738
June	1st to 10th	Night	14% 6% 2 5% 4 3 5% 4 6% 7% 44%	1520
	11th to 20th	Night	12% 6% 3 5% 5% 5% 4 5% 5% 10% 41%	1520
	21st to end	Night	11% 5% 2 5% 5% 4 6% 4 7% 9% 42%	1520
July	1st to 10th	Night	9% 6% 2 7% 5% 5% 6% 4 7% 9% 41%	2520
	11th to 20th	Night	8% 6% 2 7% 5% 5% 6% 5% 7% 10% 40%	2520
	21st to end	Night	15% 7% 3 5% 4 5% 5% 4 5% 7% 40%	2987
August	1st to 10th	Night	19% 7% 3 6% 4 4 3 4 6% 8% 35%	2825
	11th to 20th	Night	14% 8% 3 7% 4 4 4 3 6% 7% 40%	2903
	21st to end	Night	10% 5% 2 6% 4 5% 4 4 6% 8% 45%	3476
September	1st to 10th	Night	14% 6% 2 6% 4 4 3 2 5% 6% 47%	1900
	11th to 20th	Night	11% 5% 3 4 4 3 4 3 5% 7% 53%	1900
	21st to end	Night	19% 7% 2 7% 4 3 5% 3 5% 6% 40%	2164
October	1st to 10th	Night	19% 7% 2 5% 4 3 3 2 5% 6% 43%	2280
	11th to 20th	Night	15% 7% 2 5% 3 4 4 3 5% 7% 45%	2280
	21st to end	Night	18% 7% 2 6% 3 3 4 4 5% 7% 41%	2508
November	1st to 10th	Night	11% 6% 2 5% 4 4 3 3 5% 6% 51%	2521
	11th to 20th	Night	15% 9% 3 7% 5% 3 3 3 5% 6% 41%	2655
	21st to end	Night	16% 7% 3 7% 6% 4 5% 4 5% 8% 38%	2800
December	1st to 10th	Night	13% 10% 3 8% 5% 4 5% 3 5% 7% 38%	4580
	11th to 20th	Night	21% 9% 3 7% 4 4 4 3 5% 5% 35%	5208
	21st to end	Night	18% 11% 3 9% 6% 5% 4 4 5% 6% 29%	6996

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	46% 6% 15% 22% 9% 2	2566
	11th to 20th	Day	58% 6% 12% 12% 10% 2	2722
	21st to end	Day	57% 7% 11% 18% 6% 1	3124
February	1st to 10th	Day	50% 7% 12% 20% 10% 1	1710
	11th to 20th	Day	47% 6% 12% 23% 11% 2	1718
	21st to end	Day	52% 4 11% 20% 9% 3	1570
March	1st to 10th	Day	49% 7% 10% 24% 8% 2	3300
	11th to 20th	Day	38% 6% 15% 25% 13% 3	3480
	21st to end	Day	46% 5% 9% 21% 17% 2	3928
April	1st to 10th	Day	48% 6% 10% 19% 13% 4	2280
	11th to 20th	Day	43% 6% 11% 21% 15% 4	2254
	21st to end	Day	43% 6% 11% 22% 15% 4	2280
May	1st to 10th	Day	53% 6% 8% 20% 10% 2	4142
	11th to 20th	Day	54% 9% 12% 16% 8% 2	4402
	21st to end	Day	35% 8% 13% 25% 16% 2	4837
June	1st to 10th	Day	41% 8% 12% 22% 15% 1	2660
	11th to 20th	Day	42% 8% 14% 22% 12% 2	2660
	21st to end	Day	36% 9% 14% 26% 15% 1	2660
July	1st to 10th	Day	43% 7% 13% 24% 13% 2	4370
	11th to 20th	Day	38% 6% 15% 26% 14% 1	4365
	21st to end	Day	47% 5% 10% 19% 17% 1	4416
August	1st to 10th	Day	49% 7% 14% 22% 9%	4091
	11th to 20th	Day	41% 5% 10% 30% 13% 1	3931
	21st to end	Day	35% 5% 11% 31% 17% 2	4180
September	1st to 10th	Day	39% 6% 12% 21% 19% 3	2280
	11th to 20th	Day	33% 6% 11% 24% 22% 3	2280
	21st to end	Day	47% 6% 9% 17% 19% 2	2010
October	1st to 10th	Day	38% 4 8% 24% 21% 4	3160
	11th to 20th	Day	33% 3 11% 27% 20% 5%	3140
	21st to end	Day	29% 4 13% 29% 23% 2	3428
November	1st to 10th	Day	35% 5% 15% 23% 19% 3	1775
	11th to 20th	Day	42% 5% 13% 23% 15% 3	1741
	21st to end	Day	45% 7% 12% 27% 8% 1	1600
December	1st to 10th	Day	49% 4 15% 23% 9% 2	2600
	11th to 20th	Day	50% 4 14% 25% 6% 1	2986
	21st to end	Day	54% 6% 16% 14% 9% 1	3960
January	1st to 10th	Night	45% 8% 14% 22% 9% 2	4514
	11th to 20th	Night	51% 6% 15% 18% 9% 1	4234
	21st to end	Night	53% 6% 10% 21% 8% 1	4532
February	1st to 10th	Night	47% 7% 13% 23% 9% 1	2470
	11th to 20th	Night	48% 5% 13% 19% 15% 1	2358
	21st to end	Night	49% 5% 11% 19% 14% 3	1884
March	1st to 10th	Night	50% 6% 10% 22% 11% 1	3552
	11th to 20th	Night	38% 7% 15% 28% 12% 2	3480
	21st to end	Night	42% 5% 8% 20% 21% 4	3702
April	1st to 10th	Night	48% 5% 11% 19% 14% 3	1900
	11th to 20th	Night	41% 7% 11% 20% 18% 2	1875
	21st to end	Night	41% 6% 11% 21% 17% 4	1900
May	1st to 10th	Night	54% 7% 8% 19% 10% 2	2829
	11th to 20th	Night	53% 10% 13% 12% 10% 1	2496
	21st to end	Night	39% 9% 13% 22% 13% 5%	2739
June	1st to 10th	Night	37% 8% 12% 22% 20% 2	1520
	11th to 20th	Night	38% 8% 13% 23% 16% 2	1520
	21st to end	Night	36% 8% 15% 26% 15% 1	1520
July	1st to 10th	Night	40% 7% 17% 16% 16% 5%	2480
	11th to 20th	Night	39% 6% 13% 25% 15% 1	2472
	21st to end	Night	43% 5% 13% 16% 21% 2	2892
August	1st to 10th	Night	48% 5% 15% 21% 9%	2814
	11th to 20th	Night	43% 6% 10% 24% 16% 1	2930
	21st to end	Night	35% 5% 11% 31% 16% 1	3476
September	1st to 10th	Night	38% 6% 10% 22% 21% 3	1900
	11th to 20th	Night	32% 5% 9% 27% 23% 3	1900
	21st to end	Night	45% 4 9% 19% 21% 2	2164
October	1st to 10th	Night	42% 3 9% 23% 21% 1	3800
	11th to 20th	Night	31% 4 9% 29% 22% 6%	3779
	21st to end	Night	29% 4 13% 30% 22% 3	4120
November	1st to 10th	Night	33% 5% 12% 26% 20% 4	2521
	11th to 20th	Night	42% 4 10% 24% 16% 4	2655
	21st to end	Night	43% 6% 13% 25% 11% 2	2800
December	1st to 10th	Night	46% 4 14% 27% 9%	4580
	11th to 20th	Night	50% 4 14% 22% 10% 1	5208
	21st to end	Night	53% 5% 12% 17% 13%	6996

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	37% 22% 28% 9% 4	192
	11th to 20th	Day	43% 18% 30% 8% 1	239
	21st to end	Day	29% 28% 30% 10% 3	297
February	1st to 10th	Day	32% 26% 32% 7% 2	270
	11th to 20th	Day	36% 26% 31% 6% 1	316
	21st to end	Day	36% 19% 29% 14% 3	382
March	1st to 10th	Day	34% 18% 28% 16% 4	460
	11th to 20th	Day	31% 25% 27% 13% 3 1	460
	21st to end	Day	30% 24% 27% 13% 5% 2	506
April	1st to 10th	Day	31% 20% 27% 15% 5% 1	460
	11th to 20th	Day	25% 23% 25% 16% 8% 3	452
	21st to end	Day	28% 17% 35% 12% 6% 3	460
May	1st to 10th	Day	33% 16% 28% 14% 7% 2	463
	11th to 20th	Day	27% 14% 28% 20% 9% 2	487
	21st to end	Day	18% 10% 29% 24% 15% 5%	529
June	1st to 10th	Day	20% 13% 26% 25% 13% 3	490
	11th to 20th	Day	19% 10% 28% 27% 13% 3	490
	21st to end	Day	14% 12% 32% 27% 13% 3	490
July	1st to 10th	Day	13% 6% 25% 27% 22% 7%	485
	11th to 20th	Day	8% 5% 29% 33% 21% 5%	484
	21st to end	Day	13% 5% 28% 33% 17% 5%	532
August	1st to 10th	Day	13% 7% 23% 28% 21% 7%	486
	11th to 20th	Day	11% 5% 24% 33% 19% 7%	479
	21st to end	Day	13% 6% 27% 29% 13% 12%	539
September	1st to 10th	Day	19% 9% 21% 23% 17% 11%	490
	11th to 20th	Day	13% 7% 24% 29% 19% 9%	490
	21st to end	Day	30% 11% 22% 19% 13% 4	490
October	1st to 10th	Day	24% 8% 24% 22% 16% 7%	490
	11th to 20th	Day	22% 14% 29% 24% 10% 2	490
	21st to end	Day	22% 16% 32% 21% 9% 1	539
November	1st to 10th	Day	20% 16% 27% 24% 10% 2	402
	11th to 20th	Day	28% 16% 30% 17% 8% 1	341
	21st to end	Day	33% 19% 34% 11% 4 1	200
December	1st to 10th	Day	33% 23% 31% 9% 4 1	200
	11th to 20th	Day	37% 21% 32% 8% 3	200
	21st to end	Day	30% 21% 33% 13% 3	220
January	1st to 10th	Night	25% 21% 32% 19% 3	785
	11th to 20th	Night	27% 17% 30% 23% 3	760
	21st to end	Night	21% 22% 33% 22% 2	836
February	1st to 10th	Night	25% 19% 30% 24% 2	760
	11th to 20th	Night	26% 24% 33% 16% 1	743
	21st to end	Night	29% 22% 29% 17% 3	628
March	1st to 10th	Night	25% 19% 32% 20% 4	760
	11th to 20th	Night	27% 19% 30% 19% 5% 1	760
	21st to end	Night	23% 20% 32% 18% 6%	836
April	1st to 10th	Night	25% 19% 31% 20% 5%	760
	11th to 20th	Night	20% 15% 35% 23% 7% 1	751
	21st to end	Night	22% 14% 28% 29% 6% 1	760
May	1st to 10th	Night	26% 9% 27% 26% 12%	572
	11th to 20th	Night	20% 6% 31% 32% 11%	374
	21st to end	Night	14% 8% 21% 39% 17% 1	411
June	1st to 10th	Night	16% 6% 23% 35% 20%	380
	11th to 20th	Night	15% 4 24% 41% 15% 1	380
	21st to end	Night	12% 4 24% 45% 14% 1	380
July	1st to 10th	Night	14% 3 19% 41% 20% 3	370
	11th to 20th	Night	10% 2 14% 44% 28% 2	368
	21st to end	Night	12% 3 19% 39% 25% 2	563
August	1st to 10th	Night	15% 2 11% 43% 28% 1	567
	11th to 20th	Night	14% 4 12% 37% 29% 4	630
	21st to end	Night	12% 4 18% 36% 27% 3	836
September	1st to 10th	Night	16% 4 21% 35% 21% 3	760
	11th to 20th	Night	13% 5% 18% 35% 25% 5%	760
	21st to end	Night	21% 8% 20% 30% 19% 2	760
October	1st to 10th	Night	23% 8% 19% 28% 19% 3	760
	11th to 20th	Night	18% 12% 26% 32% 12% 1	760
	21st to end	Night	23% 12% 28% 28% 9%	836
November	1st to 10th	Night	15% 13% 30% 30% 10% 1	780
	11th to 20th	Night	21% 19% 28% 24% 7% 1	800
	21st to end	Night	23% 17% 30% 23% 7%	800
December	1st to 10th	Night	26% 19% 30% 21% 4	800
	11th to 20th	Night	23% 18% 31% 25% 3	800
	21st to end	Night	24% 20% 27% 27% 2	880

Page generated at 2025-01-04 03:24:02. Version ac07

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