Otter Lake Scout Camp
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Otter Lake Scout Camp clear sky chart from 2005-11-06 to 2026-06-01.

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% 10% 3 8% 5% 4 4 4 5% 7% 32%	132494
	Night	16% 11% 4 9% 5% 5% 4 3 5% 6% 31%	130652
Transparency	Day	50% 5% 11% 21% 11% 1	135998
	Night	52% 5% 11% 20% 11% 1	135235
Seeing	Day	24% 15% 31% 19% 8% 2	16430
	Night	23% 13% 30% 24% 9% 1	25668

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	13% 15% 5% 11% 7% 5% 5% 3 5% 6% 25%	4661
	11th to 20th	Day	11% 21% 9% 15% 7% 5% 5% 3 3 4 17%	4650
	21st to end	Day	11% 17% 7% 15% 7% 6% 5% 4 4 4 20%	5581
February	1st to 10th	Day	15% 16% 4 11% 6% 5% 5% 5% 5% 5% 24%	1890
	11th to 20th	Day	12% 16% 4 12% 7% 5% 4 3 4 6% 26%	1843
	21st to end	Day	19% 15% 4 10% 7% 5% 5% 3 5% 5% 22%	1714
March	1st to 10th	Day	19% 14% 4 10% 5% 4 4 2 4 5% 29%	4706
	11th to 20th	Day	11% 14% 4 9% 6% 5% 5% 4 6% 6% 31%	5090
	21st to end	Day	19% 11% 3 8% 5% 3 3 3 3 4 37%	5815
April	1st to 10th	Day	20% 14% 3 7% 5% 3 4 3 4 5% 32%	2520
	11th to 20th	Day	22% 9% 3 7% 3 3 4 3 4 5% 36%	2494
	21st to end	Day	22% 11% 3 7% 5% 4 4 3 4 5% 32%	2631
May	1st to 10th	Day	24% 10% 4 8% 5% 5% 4 3 5% 6% 27%	6475
	11th to 20th	Day	18% 8% 3 8% 5% 4 5% 3 5% 7% 34%	6458
	21st to end	Day	20% 8% 3 7% 4 4 4 4 6% 7% 34%	7103
June	1st to 10th	Day	19% 8% 3 7% 5% 4 4 5% 6% 7% 31%	2800
	11th to 20th	Day	16% 5% 2 6% 5% 4 5% 4 6% 9% 38%	2800
	21st to end	Day	17% 8% 2 6% 5% 4 4 5% 6% 8% 34%	2800
July	1st to 10th	Day	11% 6% 3 7% 5% 5% 6% 4 8% 9% 36%	6360
	11th to 20th	Day	10% 5% 2 6% 4 5% 5% 5% 7% 8% 43%	6360
	21st to end	Day	9% 5% 2 6% 4 4 5% 5% 7% 9% 44%	6926
August	1st to 10th	Day	16% 7% 3 7% 4 4 4 3 6% 8% 37%	4343
	11th to 20th	Day	16% 7% 2 6% 4 4 5% 5% 6% 9% 36%	4150
	21st to end	Day	15% 6% 2 6% 4 4 4 4 7% 9% 39%	4312
September	1st to 10th	Day	12% 6% 3 6% 4 4 5% 4 6% 7% 43%	2400
	11th to 20th	Day	12% 5% 2 5% 5% 4 4 3 4 7% 50%	2400
	21st to end	Day	18% 6% 3 6% 4 4 3 4 5% 7% 40%	2117
October	1st to 10th	Day	19% 9% 2 6% 4 4 4 4 5% 5% 39%	2000
	11th to 20th	Day	20% 8% 3 7% 6% 4 4 4 6% 7% 31%	2000
	21st to end	Day	25% 10% 3 7% 5% 4 5% 3 4 6% 27%	2095
November	1st to 10th	Day	16% 8% 3 8% 6% 4 5% 5% 5% 7% 33%	1846
	11th to 20th	Day	16% 12% 4 9% 6% 5% 3 3 5% 6% 31%	1680
	21st to end	Day	21% 15% 5% 7% 6% 4 5% 4 5% 5% 24%	1680
December	1st to 10th	Day	21% 16% 5% 11% 6% 5% 4 3 5% 6% 19%	2680
	11th to 20th	Day	18% 20% 5% 10% 5% 4 4 3 4 4 23%	3066
	21st to end	Day	22% 16% 5% 12% 6% 4 3 3 3 4 23%	4048
January	1st to 10th	Night	15% 15% 6% 13% 7% 6% 4 3 4 5% 22%	8234
	11th to 20th	Night	12% 18% 6% 16% 8% 6% 5% 4 4 5% 16%	8235
	21st to end	Night	13% 14% 6% 12% 7% 6% 5% 4 5% 5% 24%	8599
February	1st to 10th	Night	15% 14% 5% 10% 7% 5% 5% 4 5% 6% 23%	2730
	11th to 20th	Night	14% 14% 5% 11% 5% 5% 4 3 4 5% 29%	2663
	21st to end	Night	16% 13% 4 9% 6% 5% 4 3 5% 6% 28%	2092
March	1st to 10th	Night	20% 13% 4 9% 5% 5% 4 3 4 4 30%	5349
	11th to 20th	Night	14% 12% 4 8% 5% 4 5% 4 6% 9% 31%	5089
	21st to end	Night	19% 10% 3 8% 4 4 4 3 4 6% 34%	5359
April	1st to 10th	Night	22% 10% 4 7% 4 3 4 3 4 5% 33%	2100
	11th to 20th	Night	20% 9% 3 7% 4 4 3 3 5% 5% 37%	2075
	21st to end	Night	21% 10% 3 6% 4 4 4 3 5% 6% 33%	2006
May	1st to 10th	Night	26% 11% 3 7% 4 4 5% 4 5% 6% 26%	3685
	11th to 20th	Night	16% 8% 3 6% 3 4 4 3 5% 7% 41%	3655
	21st to end	Night	18% 8% 2 6% 5% 4 5% 4 6% 7% 35%	4014
June	1st to 10th	Night	15% 7% 3 7% 6% 5% 5% 5% 6% 7% 35%	1600
	11th to 20th	Night	14% 6% 2 5% 5% 4 4 4 7% 8% 42%	1600
	21st to end	Night	17% 7% 2 7% 5% 4 6% 4 5% 8% 37%	1600
July	1st to 10th	Night	12% 6% 3 7% 5% 5% 6% 4 7% 9% 37%	3600
	11th to 20th	Night	12% 6% 2 6% 4 4 4 4 6% 8% 45%	3600
	21st to end	Night	9% 5% 2 5% 4 4 5% 4 6% 8% 50%	3926
August	1st to 10th	Night	11% 7% 3 6% 4 4 4 4 6% 8% 43%	2803
	11th to 20th	Night	12% 8% 3 6% 4 4 3 3 5% 7% 44%	2875
	21st to end	Night	10% 5% 2 6% 5% 5% 5% 5% 8% 9% 41%	3576
September	1st to 10th	Night	11% 6% 2 7% 4 3 5% 3 5% 7% 48%	2000
	11th to 20th	Night	12% 4 2 5% 3 3 4 3 6% 6% 53%	2000
	21st to end	Night	18% 6% 3 5% 5% 4 4 3 5% 6% 42%	2278
October	1st to 10th	Night	16% 7% 3 7% 5% 4 4 4 5% 6% 40%	2400
	11th to 20th	Night	20% 9% 3 7% 5% 4 5% 4 5% 6% 32%	2400
	21st to end	Night	21% 9% 3 8% 5% 5% 5% 3 4 6% 31%	2744
November	1st to 10th	Night	18% 10% 3 7% 5% 3 4 3 6% 6% 36%	2667
	11th to 20th	Night	17% 11% 3 7% 4 4 5% 4 5% 6% 33%	2940
	21st to end	Night	20% 12% 4 9% 5% 5% 5% 4 5% 7% 25%	2940
December	1st to 10th	Night	19% 16% 5% 11% 7% 5% 5% 4 5% 6% 18%	4720
	11th to 20th	Night	22% 16% 4 8% 5% 4 3 3 4 5% 25%	5348
	21st to end	Night	26% 16% 4 10% 5% 4 3 2 5% 4 21%	7150

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	59% 6% 10% 18% 6% 1	4662
	11th to 20th	Day	72% 4 8% 8% 7% 1	4680
	21st to end	Day	67% 4 7% 10% 10% 1	5581
February	1st to 10th	Day	61% 4 9% 18% 6% 1	1890
	11th to 20th	Day	61% 5% 9% 16% 9% 1	1852
	21st to end	Day	64% 4 8% 12% 10% 1	1714
March	1st to 10th	Day	57% 4 9% 14% 14% 3	4709
	11th to 20th	Day	52% 5% 16% 14% 11% 2	5090
	21st to end	Day	50% 4 5% 20% 17% 3	5815
April	1st to 10th	Day	56% 4 7% 18% 13% 3	2520
	11th to 20th	Day	50% 5% 6% 21% 15% 2	2494
	21st to end	Day	54% 4 8% 18% 13% 3	2631
May	1st to 10th	Day	58% 6% 8% 18% 9% 2	6486
	11th to 20th	Day	49% 6% 11% 19% 14% 1	6462
	21st to end	Day	48% 5% 13% 22% 10% 1	7103
June	1st to 10th	Day	49% 7% 10% 20% 13% 1	2800
	11th to 20th	Day	41% 6% 11% 27% 13% 2	2800
	21st to end	Day	45% 7% 14% 22% 11% 1	2800
July	1st to 10th	Day	41% 6% 14% 28% 11%	6290
	11th to 20th	Day	36% 6% 14% 29% 15%	6285
	21st to end	Day	35% 6% 14% 35% 10%	6728
August	1st to 10th	Day	44% 6% 14% 25% 10% 1	4329
	11th to 20th	Day	43% 6% 13% 27% 10% 1	4189
	21st to end	Day	40% 5% 14% 30% 11%	4312
September	1st to 10th	Day	38% 5% 15% 29% 12% 1	2400
	11th to 20th	Day	34% 5% 12% 32% 16% 1	2400
	21st to end	Day	43% 6% 13% 27% 10%	2117
October	1st to 10th	Day	41% 5% 13% 30% 10%	3260
	11th to 20th	Day	45% 5% 14% 28% 8% 1	3240
	21st to end	Day	50% 5% 13% 24% 8%	3359
November	1st to 10th	Day	49% 7% 12% 23% 9% 1	1846
	11th to 20th	Day	54% 5% 10% 19% 11% 1	1680
	21st to end	Day	60% 7% 12% 13% 8%	1680
December	1st to 10th	Day	66% 4 15% 10% 4	2680
	11th to 20th	Day	66% 5% 9% 13% 7%	3066
	21st to end	Day	65% 5% 7% 17% 6%	4048
January	1st to 10th	Night	64% 5% 12% 13% 6%	8234
	11th to 20th	Night	69% 5% 8% 10% 7%	8280
	21st to end	Night	62% 5% 7% 13% 12% 1	8599
February	1st to 10th	Night	60% 5% 10% 17% 7% 1	2730
	11th to 20th	Night	57% 4 9% 19% 9% 1	2665
	21st to end	Night	58% 5% 9% 18% 9% 1	2092
March	1st to 10th	Night	58% 4 6% 17% 11% 4	5359
	11th to 20th	Night	50% 5% 17% 17% 9% 3	5090
	21st to end	Night	50% 5% 6% 21% 16% 2	5359
April	1st to 10th	Night	52% 4 7% 20% 15% 2	2100
	11th to 20th	Night	50% 3 9% 20% 17% 2	2075
	21st to end	Night	52% 4 8% 17% 16% 3	2006
May	1st to 10th	Night	59% 5% 8% 16% 9% 3	3691
	11th to 20th	Night	43% 6% 14% 21% 14% 2	3656
	21st to end	Night	47% 6% 12% 20% 14% 1	4015
June	1st to 10th	Night	47% 6% 12% 21% 13% 1	1600
	11th to 20th	Night	38% 6% 13% 22% 19% 2	1600
	21st to end	Night	45% 7% 12% 22% 13% 1	1600
July	1st to 10th	Night	41% 6% 15% 21% 16% 1	3560
	11th to 20th	Night	36% 6% 11% 33% 13%	3552
	21st to end	Night	33% 6% 12% 35% 13% 2	3809
August	1st to 10th	Night	39% 6% 14% 27% 14% 1	2793
	11th to 20th	Night	38% 5% 13% 32% 10% 1	2902
	21st to end	Night	36% 7% 14% 30% 11% 1	3576
September	1st to 10th	Night	37% 5% 12% 32% 14% 1	2000
	11th to 20th	Night	30% 6% 13% 35% 14% 1	2000
	21st to end	Night	42% 5% 11% 29% 13% 1	2278
October	1st to 10th	Night	38% 4 11% 28% 18% 1	3920
	11th to 20th	Night	44% 4 13% 27% 11%	3899
	21st to end	Night	49% 5% 13% 24% 9%	4430
November	1st to 10th	Night	47% 6% 12% 23% 11% 1	2667
	11th to 20th	Night	50% 6% 12% 20% 11% 2	2940
	21st to end	Night	59% 6% 12% 16% 6%	2940
December	1st to 10th	Night	65% 5% 12% 14% 4	4720
	11th to 20th	Night	61% 5% 9% 15% 10% 1	5348
	21st to end	Night	66% 4 7% 11% 10%	7150

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	26% 18% 39% 14% 3 1	220
	11th to 20th	Day	34% 18% 30% 15% 2 1	220
	21st to end	Day	27% 24% 28% 17% 4	327
February	1st to 10th	Day	33% 23% 31% 11% 2	330
	11th to 20th	Day	31% 28% 34% 8%	330
	21st to end	Day	33% 19% 35% 11% 1	430
March	1st to 10th	Day	27% 21% 33% 15% 4	540
	11th to 20th	Day	34% 19% 30% 14% 3 1	540
	21st to end	Day	33% 21% 29% 12% 5% 1	594
April	1st to 10th	Day	31% 22% 31% 11% 4	540
	11th to 20th	Day	34% 21% 24% 12% 6% 3	532
	21st to end	Day	30% 20% 32% 11% 5% 2	540
May	1st to 10th	Day	27% 16% 30% 20% 6% 1	543
	11th to 20th	Day	21% 14% 37% 19% 8% 2	567
	21st to end	Day	20% 17% 30% 22% 8% 2	617
June	1st to 10th	Day	25% 12% 33% 22% 7% 2	530
	11th to 20th	Day	18% 15% 35% 19% 11% 2	530
	21st to end	Day	23% 13% 32% 21% 9% 2	530
July	1st to 10th	Day	14% 9% 33% 27% 14% 3	525
	11th to 20th	Day	15% 11% 30% 27% 14% 4	524
	21st to end	Day	14% 8% 38% 27% 9% 4	576
August	1st to 10th	Day	16% 5% 32% 29% 14% 4	526
	11th to 20th	Day	14% 6% 28% 30% 15% 6%	519
	21st to end	Day	15% 10% 31% 26% 11% 6%	583
September	1st to 10th	Day	15% 9% 32% 26% 11% 7%	530
	11th to 20th	Day	12% 7% 24% 28% 17% 11%	530
	21st to end	Day	19% 11% 30% 25% 12% 3	530
October	1st to 10th	Day	28% 12% 26% 18% 11% 4	530
	11th to 20th	Day	26% 20% 32% 15% 6% 2	530
	21st to end	Day	31% 17% 27% 21% 4	525
November	1st to 10th	Day	30% 17% 29% 18% 7%	420
	11th to 20th	Day	28% 13% 41% 9% 7% 2	220
	21st to end	Day	32% 20% 32% 12% 4	220
December	1st to 10th	Day	35% 20% 29% 13% 3	220
	11th to 20th	Day	34% 22% 34% 8% 2	220
	21st to end	Day	36% 17% 33% 11% 4	242
January	1st to 10th	Night	30% 16% 32% 18% 4	840
	11th to 20th	Night	31% 19% 28% 17% 5%	840
	21st to end	Night	22% 16% 35% 21% 5%	924
February	1st to 10th	Night	26% 18% 33% 20% 2	840
	11th to 20th	Night	25% 18% 38% 16% 3	823
	21st to end	Night	26% 19% 35% 17% 3	692
March	1st to 10th	Night	25% 16% 35% 20% 3	840
	11th to 20th	Night	29% 18% 28% 21% 4 1	840
	21st to end	Night	25% 16% 33% 19% 7%	924
April	1st to 10th	Night	27% 17% 33% 21% 3	840
	11th to 20th	Night	24% 20% 31% 17% 7%	831
	21st to end	Night	27% 12% 30% 23% 8%	746
May	1st to 10th	Night	27% 8% 26% 28% 10% 1	431
	11th to 20th	Night	15% 10% 38% 31% 7%	414
	21st to end	Night	14% 9% 36% 29% 10% 1	455
June	1st to 10th	Night	16% 9% 34% 32% 10% 1	400
	11th to 20th	Night	18% 8% 30% 32% 12% 1	400
	21st to end	Night	19% 5% 26% 36% 13%	400
July	1st to 10th	Night	10% 5% 30% 38% 17%	390
	11th to 20th	Night	12% 3 29% 38% 16% 1	388
	21st to end	Night	12% 5% 27% 41% 14% 1	438
August	1st to 10th	Night	13% 3 25% 36% 22% 1	524
	11th to 20th	Night	15% 3 24% 33% 22% 3	594
	21st to end	Night	12% 6% 29% 35% 16% 2	870
September	1st to 10th	Night	15% 6% 29% 32% 16% 3	800
	11th to 20th	Night	14% 6% 20% 28% 26% 6%	800
	21st to end	Night	20% 9% 23% 29% 17% 3	800
October	1st to 10th	Night	21% 11% 28% 21% 18% 2	800
	11th to 20th	Night	26% 13% 30% 23% 8% 1	800
	21st to end	Night	27% 15% 29% 24% 6%	880
November	1st to 10th	Night	27% 14% 30% 22% 7%	820
	11th to 20th	Night	24% 16% 32% 19% 8% 1	840
	21st to end	Night	30% 18% 28% 16% 7%	840
December	1st to 10th	Night	30% 17% 29% 20% 4	840
	11th to 20th	Night	29% 19% 34% 15% 3 1	840
	21st to end	Night	35% 16% 30% 17% 2	924

Page generated at 2026-05-29 01:53:27. Version ac07

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