Ocqueoc Outdoor Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ocqueoc Outdoor Center clear sky chart from 2005-11-06 to 2026-02-01.

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	14% 11% 4 9% 5% 5% 4 4 5% 7% 33%	127085
	Night	14% 12% 5% 11% 6% 5% 4 3 5% 6% 29%	125142
Transparency	Day	51% 5% 11% 21% 11% 1	130575
	Night	54% 6% 12% 18% 9% 1	129740
Seeing	Day	21% 13% 30% 23% 10% 3	17119
	Night	21% 11% 29% 27% 10% 1	26734

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	10% 17% 9% 23% 10% 5% 5% 3 4 4 10%	3664
	11th to 20th	Day	11% 18% 7% 23% 13% 7% 4 3 4 4 6%	3669
	21st to end	Day	13% 18% 8% 18% 7% 6% 5% 4 5% 5% 12%	4070
February	1st to 10th	Day	9% 18% 7% 14% 11% 6% 5% 4 4 6% 17%	1770
	11th to 20th	Day	11% 16% 6% 14% 9% 6% 5% 2 4 5% 22%	1858
	21st to end	Day	11% 18% 6% 13% 8% 5% 5% 4 4 5% 22%	1650
March	1st to 10th	Day	13% 11% 3 10% 4 5% 5% 4 5% 7% 32%	4478
	11th to 20th	Day	11% 13% 5% 11% 6% 5% 5% 4 5% 6% 28%	4975
	21st to end	Day	19% 12% 8% 11% 5% 5% 5% 3 4 4 23%	5500
April	1st to 10th	Day	18% 14% 4 8% 5% 4 4 3 5% 6% 28%	2400
	11th to 20th	Day	18% 13% 4 7% 4 3 5% 4 4 6% 34%	2546
	21st to end	Day	16% 10% 3 8% 4 4 4 4 5% 7% 33%	2600
May	1st to 10th	Day	17% 8% 2 6% 4 3 4 3 5% 7% 41%	5888
	11th to 20th	Day	11% 8% 3 8% 5% 4 5% 4 5% 6% 43%	5942
	21st to end	Day	15% 7% 2 6% 4 4 3 3 5% 7% 44%	7263
June	1st to 10th	Day	12% 7% 2 7% 5% 4 4 4 6% 8% 43%	3000
	11th to 20th	Day	12% 6% 2 6% 5% 5% 5% 4 7% 8% 40%	3000
	21st to end	Day	13% 7% 3 6% 4 5% 4 4 6% 8% 40%	3000
July	1st to 10th	Day	15% 6% 2 6% 4 3 4 3 5% 7% 45%	6666
	11th to 20th	Day	10% 5% 2 5% 4 4 5% 4 6% 8% 48%	6360
	21st to end	Day	9% 5% 2 6% 4 4 4 4 5% 9% 49%	6926
August	1st to 10th	Day	8% 6% 2 6% 5% 5% 6% 4 7% 10% 42%	4283
	11th to 20th	Day	13% 6% 2 6% 4 4 4 4 6% 7% 45%	4174
	21st to end	Day	12% 6% 3 7% 5% 4 4 3 6% 7% 44%	4650
September	1st to 10th	Day	13% 7% 3 7% 4 4 4 4 6% 7% 40%	2321
	11th to 20th	Day	13% 5% 2 5% 3 5% 4 4 6% 7% 45%	2200
	21st to end	Day	17% 9% 3 6% 4 4 4 4 6% 8% 36%	2200
October	1st to 10th	Day	18% 9% 4 6% 4 4 4 3 6% 7% 35%	2150
	11th to 20th	Day	22% 13% 3 10% 6% 5% 4 4 5% 7% 21%	1945
	21st to end	Day	21% 15% 5% 10% 5% 5% 4 4 5% 6% 19%	1980
November	1st to 10th	Day	16% 17% 5% 9% 5% 4 4 3 5% 7% 24%	1852
	11th to 20th	Day	13% 19% 5% 12% 7% 6% 6% 4 6% 6% 17%	1822
	21st to end	Day	19% 22% 7% 11% 6% 5% 4 2 5% 5% 14%	1680
December	1st to 10th	Day	13% 23% 10% 16% 7% 5% 5% 4 4 4 8%	2359
	11th to 20th	Day	13% 20% 7% 17% 8% 7% 5% 3 4 4 12%	2691
	21st to end	Day	23% 22% 9% 15% 5% 6% 4 2 3 4 7%	3553
January	1st to 10th	Night	11% 14% 6% 26% 10% 6% 5% 3 4 5% 10%	6517
	11th to 20th	Night	12% 15% 7% 21% 10% 7% 5% 3 5% 4 10%	6456
	21st to end	Night	10% 18% 8% 16% 7% 7% 6% 4 5% 4 16%	7150
February	1st to 10th	Night	9% 16% 6% 13% 8% 6% 6% 5% 6% 5% 20%	2629
	11th to 20th	Night	11% 16% 5% 13% 6% 5% 6% 3 5% 6% 23%	2424
	21st to end	Night	14% 14% 5% 12% 7% 5% 4 4 4 6% 23%	1980
March	1st to 10th	Night	15% 11% 4 8% 6% 4 3 3 4 6% 35%	5362
	11th to 20th	Night	11% 13% 4 8% 5% 4 5% 4 5% 7% 33%	4984
	21st to end	Night	21% 12% 6% 9% 4 4 4 3 4 5% 29%	5467
April	1st to 10th	Night	19% 12% 3 8% 4 4 4 5% 5% 6% 29%	2009
	11th to 20th	Night	19% 10% 4 6% 4 3 3 3 5% 6% 35%	1802
	21st to end	Night	16% 11% 4 8% 5% 4 4 4 5% 6% 33%	1800
May	1st to 10th	Night	15% 9% 3 7% 5% 5% 4 4 4 5% 39%	4053
	11th to 20th	Night	14% 8% 2 7% 5% 4 5% 3 5% 6% 41%	3954
	21st to end	Night	19% 9% 2 5% 3 3 3 3 5% 6% 41%	3634
June	1st to 10th	Night	13% 7% 2 7% 4 4 4 3 6% 8% 42%	1400
	11th to 20th	Night	11% 4 2 7% 5% 5% 6% 4 7% 9% 40%	1400
	21st to end	Night	14% 7% 3 6% 4 3 4 3 5% 8% 43%	1400
July	1st to 10th	Night	12% 5% 3 7% 4 4 4 3 6% 7% 45%	3295
	11th to 20th	Night	11% 5% 2 5% 4 4 4 3 5% 6% 52%	3620
	21st to end	Night	8% 4 2 5% 3 4 4 4 5% 8% 53%	3948
August	1st to 10th	Night	10% 5% 2 6% 4 4 5% 4 6% 8% 46%	2865
	11th to 20th	Night	15% 5% 2 4 3 3 3 2 5% 8% 49%	2875
	21st to end	Night	10% 5% 2 5% 4 4 4 3 5% 7% 52%	3246
September	1st to 10th	Night	14% 6% 2 6% 4 3 4 3 4 7% 47%	2057
	11th to 20th	Night	14% 5% 2 5% 4 3 4 3 6% 7% 47%	2200
	21st to end	Night	16% 8% 2 7% 4 4 4 4 5% 7% 39%	2200
October	1st to 10th	Night	17% 8% 3 6% 4 4 4 3 5% 6% 41%	2250
	11th to 20th	Night	22% 12% 3 8% 4 5% 5% 3 5% 6% 27%	2450
	21st to end	Night	24% 14% 3 8% 5% 5% 4 3 4 6% 24%	2860
November	1st to 10th	Night	14% 15% 3 9% 6% 5% 4 4 5% 7% 27%	2666
	11th to 20th	Night	14% 17% 5% 10% 6% 6% 4 5% 5% 6% 21%	2796
	21st to end	Night	19% 21% 5% 12% 5% 5% 4 4 5% 5% 16%	2940
December	1st to 10th	Night	12% 19% 8% 15% 7% 6% 5% 4 5% 5% 13%	5050
	11th to 20th	Night	13% 20% 7% 18% 7% 5% 4 4 4 4 14%	5736
	21st to end	Night	23% 20% 12% 13% 8% 5% 4 2 3 3 7%	7667

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	76% 6% 10% 6% 1 1	3665
	11th to 20th	Day	80% 6% 6% 6% 2	3700
	21st to end	Day	73% 6% 10% 7% 4	4070
February	1st to 10th	Day	68% 5% 10% 13% 4	1770
	11th to 20th	Day	65% 5% 9% 14% 7%	1867
	21st to end	Day	64% 5% 9% 16% 6%	1650
March	1st to 10th	Day	51% 4 16% 16% 11% 2	4480
	11th to 20th	Day	56% 6% 12% 18% 7% 1	4975
	21st to end	Day	63% 6% 7% 16% 8% 1	5500
April	1st to 10th	Day	57% 4 9% 19% 10% 1	2400
	11th to 20th	Day	51% 5% 8% 19% 15% 2	2546
	21st to end	Day	50% 5% 10% 16% 15% 3	2600
May	1st to 10th	Day	43% 6% 8% 21% 19% 3	5897
	11th to 20th	Day	40% 7% 8% 23% 19% 2	5946
	21st to end	Day	40% 5% 11% 22% 18% 5%	7263
June	1st to 10th	Day	38% 5% 11% 28% 15% 2	3000
	11th to 20th	Day	41% 6% 11% 23% 16% 2	3000
	21st to end	Day	41% 6% 12% 25% 13% 3	3000
July	1st to 10th	Day	39% 5% 12% 28% 14% 1	6596
	11th to 20th	Day	33% 5% 13% 37% 11% 1	6285
	21st to end	Day	33% 5% 11% 33% 17% 1	6728
August	1st to 10th	Day	36% 7% 13% 29% 14% 1	4268
	11th to 20th	Day	38% 6% 13% 31% 11% 1	4213
	21st to end	Day	40% 5% 14% 31% 9% 1	4649
September	1st to 10th	Day	42% 6% 10% 27% 13% 1	2321
	11th to 20th	Day	37% 6% 14% 30% 12% 1	2200
	21st to end	Day	46% 6% 15% 22% 10%	2200
October	1st to 10th	Day	36% 5% 11% 30% 17%	3501
	11th to 20th	Day	55% 5% 8% 20% 11%	3148
	21st to end	Day	61% 5% 11% 18% 5%	3180
November	1st to 10th	Day	59% 6% 10% 20% 6%	1852
	11th to 20th	Day	65% 6% 14% 10% 5%	1822
	21st to end	Day	72% 5% 12% 9% 2	1680
December	1st to 10th	Day	78% 7% 9% 5% 1	2359
	11th to 20th	Day	74% 5% 10% 7% 3	2691
	21st to end	Day	84% 3 4 5% 3	3553
January	1st to 10th	Night	75% 6% 9% 8% 2	6517
	11th to 20th	Night	74% 8% 9% 7% 3	6500
	21st to end	Night	68% 5% 11% 11% 5%	7150
February	1st to 10th	Night	65% 5% 11% 13% 6%	2629
	11th to 20th	Night	61% 6% 11% 16% 6% 1	2426
	21st to end	Night	62% 5% 12% 16% 6%	1980
March	1st to 10th	Night	50% 4 16% 19% 10% 1	5373
	11th to 20th	Night	48% 7% 18% 19% 7% 1	4985
	21st to end	Night	57% 4 10% 17% 10% 1	5467
April	1st to 10th	Night	53% 7% 8% 20% 11% 1	2009
	11th to 20th	Night	49% 4 7% 24% 13% 3	1802
	21st to end	Night	50% 6% 9% 17% 14% 4	1800
May	1st to 10th	Night	45% 7% 8% 21% 17% 3	4060
	11th to 20th	Night	42% 7% 8% 25% 17% 1	3955
	21st to end	Night	44% 6% 11% 21% 13% 5%	3635
June	1st to 10th	Night	39% 6% 10% 26% 17% 1	1400
	11th to 20th	Night	37% 7% 14% 26% 14% 2	1400
	21st to end	Night	40% 7% 12% 25% 14% 3	1400
July	1st to 10th	Night	37% 5% 15% 24% 17% 1	3258
	11th to 20th	Night	33% 5% 12% 32% 17% 1	3572
	21st to end	Night	29% 6% 14% 32% 18% 1	3832
August	1st to 10th	Night	35% 6% 16% 29% 13% 1	2856
	11th to 20th	Night	34% 5% 16% 30% 13% 1	2902
	21st to end	Night	32% 5% 16% 32% 14% 1	3246
September	1st to 10th	Night	36% 6% 14% 27% 15% 1	2057
	11th to 20th	Night	36% 6% 15% 31% 12%	2200
	21st to end	Night	43% 6% 17% 24% 10%	2200
October	1st to 10th	Night	36% 5% 12% 32% 15%	3679
	11th to 20th	Night	47% 5% 15% 20% 13%	3986
	21st to end	Night	55% 5% 14% 21% 5%	4610
November	1st to 10th	Night	55% 7% 12% 19% 7% 1	2666
	11th to 20th	Night	62% 7% 12% 13% 6% 1	2796
	21st to end	Night	69% 7% 12% 10% 3	2940
December	1st to 10th	Night	70% 8% 13% 9% 1	5050
	11th to 20th	Night	73% 6% 10% 7% 5%	5735
	21st to end	Night	83% 5% 5% 6% 2	7667

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% 16% 40% 17% 5%	320
	11th to 20th	Day	25% 12% 40% 18% 5% 1	330
	21st to end	Day	25% 17% 36% 17% 5% 1	363
February	1st to 10th	Day	24% 22% 34% 15% 4 1	300
	11th to 20th	Day	23% 25% 34% 15% 3	300
	21st to end	Day	25% 26% 35% 12% 1	249
March	1st to 10th	Day	23% 21% 38% 13% 5%	300
	11th to 20th	Day	23% 16% 36% 19% 5% 1	495
	21st to end	Day	31% 14% 27% 22% 5% 1	550
April	1st to 10th	Day	27% 17% 29% 21% 5% 1	500
	11th to 20th	Day	30% 16% 28% 16% 8% 2	492
	21st to end	Day	23% 17% 31% 19% 8% 2	500
May	1st to 10th	Day	24% 17% 29% 17% 10% 3	503
	11th to 20th	Day	19% 12% 33% 23% 9% 4	556
	21st to end	Day	18% 12% 29% 27% 11% 2	789
June	1st to 10th	Day	14% 14% 34% 27% 9% 2	730
	11th to 20th	Day	17% 10% 35% 25% 10% 2	730
	21st to end	Day	18% 8% 33% 29% 11% 1	730
July	1st to 10th	Day	12% 8% 31% 32% 14% 4	721
	11th to 20th	Day	13% 8% 31% 31% 13% 4	718
	21st to end	Day	11% 8% 31% 31% 14% 5%	794
August	1st to 10th	Day	12% 8% 24% 31% 19% 7%	563
	11th to 20th	Day	14% 5% 19% 31% 21% 9%	519
	21st to end	Day	17% 6% 26% 30% 17% 5%	583
September	1st to 10th	Day	18% 9% 26% 25% 16% 7%	530
	11th to 20th	Day	15% 5% 22% 30% 19% 9%	530
	21st to end	Day	22% 9% 22% 28% 15% 5%	530
October	1st to 10th	Day	24% 12% 26% 22% 15% 2	530
	11th to 20th	Day	28% 12% 32% 24% 3 1	475
	21st to end	Day	29% 17% 34% 15% 5% 1	363
November	1st to 10th	Day	28% 15% 34% 19% 3 1	330
	11th to 20th	Day	28% 19% 33% 16% 5%	294
	21st to end	Day	29% 20% 35% 13% 3	220
December	1st to 10th	Day	32% 15% 29% 15% 7% 2	220
	11th to 20th	Day	31% 23% 29% 13% 3	220
	21st to end	Day	31% 17% 33% 16% 2 1	242
January	1st to 10th	Night	21% 19% 34% 20% 5%	1050
	11th to 20th	Night	27% 14% 32% 21% 6% 1	1050
	21st to end	Night	19% 14% 33% 27% 6% 1	1155
February	1st to 10th	Night	18% 18% 36% 22% 6%	829
	11th to 20th	Night	22% 16% 32% 23% 5%	783
	21st to end	Night	24% 15% 34% 24% 3	660
March	1st to 10th	Night	20% 14% 33% 25% 7% 1	800
	11th to 20th	Night	21% 17% 32% 25% 6%	800
	21st to end	Night	22% 10% 31% 29% 8% 1	880
April	1st to 10th	Night	26% 11% 32% 26% 4 1	609
	11th to 20th	Night	26% 11% 27% 27% 8% 1	593
	21st to end	Night	23% 9% 32% 27% 10% 1	600
May	1st to 10th	Night	18% 7% 31% 35% 9%	600
	11th to 20th	Night	19% 7% 27% 37% 9%	591
	21st to end	Night	16% 6% 27% 35% 15%	517
June	1st to 10th	Night	17% 7% 29% 36% 11%	400
	11th to 20th	Night	12% 8% 25% 43% 13% 1	400
	21st to end	Night	20% 4 22% 39% 14% 1	400
July	1st to 10th	Night	11% 4 22% 42% 20% 1	445
	11th to 20th	Night	10% 5% 22% 35% 25% 3	582
	21st to end	Night	12% 4 23% 38% 21% 2	657
August	1st to 10th	Night	13% 2 20% 42% 22% 1	597
	11th to 20th	Night	15% 3 15% 36% 27% 4	594
	21st to end	Night	15% 5% 19% 39% 20% 2	660
September	1st to 10th	Night	17% 6% 22% 30% 21% 4	657
	11th to 20th	Night	16% 5% 22% 35% 20% 3	800
	21st to end	Night	20% 5% 22% 32% 17% 4	800
October	1st to 10th	Night	22% 8% 27% 30% 12% 1	800
	11th to 20th	Night	29% 13% 29% 23% 6%	800
	21st to end	Night	31% 10% 27% 25% 6%	880
November	1st to 10th	Night	24% 13% 31% 24% 7% 1	820
	11th to 20th	Night	25% 16% 32% 21% 5%	840
	21st to end	Night	32% 14% 34% 18% 2	840
December	1st to 10th	Night	22% 16% 36% 20% 6%	1040
	11th to 20th	Night	25% 18% 35% 16% 5% 1	1050
	21st to end	Night	31% 14% 34% 18% 3 1	1155

Page generated at 2026-01-29 01:21:40. Version ac07

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