Pine Valley Golf Club
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Pine Valley Golf Club 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	15% 6% 2 6% 4 4 4 4 6% 7% 40%	127526
	Night	15% 7% 2 6% 4 4 4 3 5% 7% 43%	124455
Transparency	Day	41% 5% 11% 23% 17% 3	131067
	Night	40% 5% 11% 23% 18% 4	129000
Seeing	Day	21% 18% 29% 20% 9% 3	16559
	Night	19% 16% 30% 25% 8% 1	25926

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% 7% 2 5% 3 3 4 3 5% 5% 49%	3677
	11th to 20th	Day	14% 8% 3 8% 5% 4 4 3 4 5% 44%	3743
	21st to end	Day	18% 8% 3 6% 4 3 3 3 4 5% 43%	4565
February	1st to 10th	Day	14% 9% 2 7% 4 5% 4 3 6% 6% 40%	1800
	11th to 20th	Day	18% 8% 2 4 4 3 4 4 5% 7% 40%	1928
	21st to end	Day	17% 10% 4 6% 4 3 3 3 4 5% 40%	1650
March	1st to 10th	Day	20% 6% 2 4 3 3 3 3 4 5% 46%	4476
	11th to 20th	Day	10% 6% 2 7% 5% 4 4 3 5% 7% 47%	4934
	21st to end	Day	18% 5% 2 6% 4 4 4 3 5% 6% 43%	5824
April	1st to 10th	Day	17% 8% 3 5% 4 4 5% 3 5% 7% 40%	2400
	11th to 20th	Day	15% 6% 2 5% 4 3 4 4 6% 8% 41%	2374
	21st to end	Day	15% 6% 2 7% 4 4 4 4 6% 8% 40%	2400
May	1st to 10th	Day	24% 8% 3 6% 4 4 4 4 5% 8% 29%	5755
	11th to 20th	Day	24% 8% 3 7% 5% 4 4 3 4 7% 33%	6318
	21st to end	Day	19% 6% 2 5% 4 4 4 4 6% 8% 37%	6949
June	1st to 10th	Day	12% 6% 2 6% 4 5% 5% 5% 7% 8% 40%	2800
	11th to 20th	Day	13% 6% 2 6% 5% 5% 6% 4 7% 8% 39%	2800
	21st to end	Day	10% 4 2 6% 4 5% 6% 4 7% 9% 42%	2800
July	1st to 10th	Day	9% 5% 2 7% 6% 6% 6% 5% 8% 10% 37%	6360
	11th to 20th	Day	11% 7% 3 8% 6% 6% 6% 5% 8% 12% 30%	6360
	21st to end	Day	10% 6% 2 7% 5% 5% 5% 5% 6% 10% 37%	6838
August	1st to 10th	Day	18% 6% 2 7% 5% 5% 5% 4 6% 8% 33%	4188
	11th to 20th	Day	13% 6% 2 6% 4 4 5% 4 7% 10% 37%	3850
	21st to end	Day	10% 6% 2 5% 4 3 5% 4 6% 8% 47%	4312
September	1st to 10th	Day	13% 6% 2 7% 5% 4 4 3 5% 6% 46%	2400
	11th to 20th	Day	13% 5% 2 5% 4 4 4 3 5% 7% 50%	2354
	21st to end	Day	18% 8% 3 7% 4 4 5% 3 4 6% 38%	2200
October	1st to 10th	Day	17% 6% 2 5% 3 3 4 3 5% 6% 46%	2026
	11th to 20th	Day	16% 6% 2 4 4 2 4 3 4 6% 50%	2000
	21st to end	Day	17% 6% 2 5% 4 3 3 3 4 7% 47%	2120
November	1st to 10th	Day	12% 5% 2 4 4 4 3 2 4 6% 53%	1851
	11th to 20th	Day	14% 6% 2 6% 4 3 4 4 6% 6% 46%	1890
	21st to end	Day	15% 6% 1 5% 4 4 4 3 5% 6% 47%	1790
December	1st to 10th	Day	13% 6% 2 5% 3 3 4 4 7% 7% 46%	2680
	11th to 20th	Day	19% 9% 2 5% 3 3 3 2 3 4 46%	3066
	21st to end	Day	15% 6% 2 5% 4 4 5% 4 7% 7% 40%	4048
January	1st to 10th	Night	14% 7% 2 5% 3 3 3 3 5% 5% 50%	6489
	11th to 20th	Night	15% 7% 2 6% 4 3 3 2 3 5% 50%	6347
	21st to end	Night	16% 7% 2 6% 4 3 4 3 5% 5% 43%	6633
February	1st to 10th	Night	17% 8% 2 7% 4 3 3 3 5% 6% 41%	2601
	11th to 20th	Night	19% 8% 2 5% 4 4 3 3 5% 6% 41%	2357
	21st to end	Night	17% 8% 2 5% 4 4 4 4 4 6% 42%	1980
March	1st to 10th	Night	18% 8% 2 5% 3 3 3 2 4 5% 45%	5364
	11th to 20th	Night	11% 9% 3 5% 4 4 3 3 4 5% 50%	5007
	21st to end	Night	15% 7% 2 6% 4 4 4 3 4 5% 44%	5106
April	1st to 10th	Night	17% 7% 3 6% 5% 4 4 3 5% 6% 40%	2000
	11th to 20th	Night	14% 7% 2 7% 4 4 4 3 5% 7% 42%	1975
	21st to end	Night	17% 6% 2 5% 4 4 4 3 5% 7% 44%	2000
May	1st to 10th	Night	20% 8% 3 8% 5% 5% 5% 4 6% 8% 28%	4198
	11th to 20th	Night	22% 9% 3 7% 4 4 3 3 5% 7% 32%	3588
	21st to end	Night	21% 6% 2 6% 4 4 3 3 5% 8% 37%	3926
June	1st to 10th	Night	14% 6% 3 6% 5% 4 4 4 6% 7% 43%	1600
	11th to 20th	Night	11% 7% 3 6% 5% 5% 4 5% 6% 8% 41%	1600
	21st to end	Night	9% 6% 2 6% 5% 4 4 5% 8% 12% 40%	1600
July	1st to 10th	Night	9% 7% 2 7% 6% 6% 6% 5% 6% 10% 36%	3600
	11th to 20th	Night	12% 8% 3 8% 5% 5% 6% 4 7% 10% 33%	3600
	21st to end	Night	11% 6% 2 6% 4 4 5% 3 6% 9% 42%	4010
August	1st to 10th	Night	20% 6% 2 6% 4 4 4 4 6% 8% 33%	2915
	11th to 20th	Night	13% 6% 3 6% 4 4 4 3 5% 7% 43%	3197
	21st to end	Night	10% 5% 2 6% 4 3 4 3 5% 7% 50%	3586
September	1st to 10th	Night	13% 6% 2 7% 4 4 4 4 4 7% 46%	2000
	11th to 20th	Night	11% 5% 2 5% 3 3 4 3 5% 7% 54%	2045
	21st to end	Night	20% 7% 2 6% 4 3 4 4 6% 7% 39%	2200
October	1st to 10th	Night	18% 5% 2 6% 4 4 3 3 4 6% 45%	2370
	11th to 20th	Night	16% 5% 2 5% 3 3 3 2 4 6% 51%	2400
	21st to end	Night	16% 7% 1 5% 3 4 3 3 5% 5% 48%	2720
November	1st to 10th	Night	11% 5% 2 5% 4 3 3 3 5% 6% 53%	2667
	11th to 20th	Night	15% 7% 2 5% 3 3 4 3 4 5% 48%	2730
	21st to end	Night	13% 6% 2 5% 4 4 4 4 6% 6% 46%	2826
December	1st to 10th	Night	13% 7% 2 5% 3 3 3 3 5% 7% 49%	4720
	11th to 20th	Night	22% 7% 2 5% 3 3 3 3 4 7% 41%	5348
	21st to end	Night	18% 7% 3 6% 4 4 4 4 5% 6% 41%	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	37% 3 8% 25% 23% 3	3678
	11th to 20th	Day	44% 3 7% 22% 17% 6%	3773
	21st to end	Day	45% 4 11% 25% 13% 2	4565
February	1st to 10th	Day	44% 4 13% 25% 11% 2	1800
	11th to 20th	Day	44% 5% 9% 24% 15% 3	1937
	21st to end	Day	46% 4 8% 22% 14% 5%	1650
March	1st to 10th	Day	40% 4 8% 25% 16% 7%	4479
	11th to 20th	Day	37% 3 9% 29% 17% 5%	4934
	21st to end	Day	42% 4 8% 17% 23% 6%	5824
April	1st to 10th	Day	43% 5% 11% 19% 16% 6%	2400
	11th to 20th	Day	40% 5% 12% 22% 16% 4	2374
	21st to end	Day	40% 6% 9% 20% 20% 4	2400
May	1st to 10th	Day	53% 6% 12% 18% 9% 1	5765
	11th to 20th	Day	52% 5% 9% 21% 12% 1	6322
	21st to end	Day	43% 7% 10% 23% 15% 1	6949
June	1st to 10th	Day	40% 8% 12% 22% 17% 2	2800
	11th to 20th	Day	41% 8% 12% 24% 13% 3	2800
	21st to end	Day	37% 8% 13% 23% 18% 2	2800
July	1st to 10th	Day	40% 10% 15% 18% 15% 2	6290
	11th to 20th	Day	44% 8% 18% 19% 10% 1	6285
	21st to end	Day	40% 7% 10% 21% 21% 1	6641
August	1st to 10th	Day	48% 7% 13% 22% 10% 1	4175
	11th to 20th	Day	40% 7% 13% 25% 14% 1	3886
	21st to end	Day	33% 7% 11% 27% 20% 2	4312
September	1st to 10th	Day	39% 6% 10% 20% 22% 3	2400
	11th to 20th	Day	34% 4 9% 25% 25% 3	2354
	21st to end	Day	48% 5% 8% 17% 20% 2	2200
October	1st to 10th	Day	35% 4 9% 18% 30% 5%	3299
	11th to 20th	Day	26% 3 9% 24% 29% 9%	3240
	21st to end	Day	26% 3 11% 28% 28% 5%	3410
November	1st to 10th	Day	33% 3 12% 27% 21% 4	1851
	11th to 20th	Day	37% 5% 9% 23% 23% 3	1890
	21st to end	Day	38% 4 12% 30% 14% 2	1790
December	1st to 10th	Day	36% 5% 17% 25% 15% 2	2680
	11th to 20th	Day	44% 3 10% 30% 10% 3	3066
	21st to end	Day	41% 5% 13% 22% 18% 2	4048
January	1st to 10th	Night	36% 3 8% 24% 22% 6%	6489
	11th to 20th	Night	39% 3 8% 24% 19% 7%	6392
	21st to end	Night	42% 3 8% 25% 19% 2	6633
February	1st to 10th	Night	44% 4 13% 24% 14% 2	2601
	11th to 20th	Night	45% 4 9% 21% 17% 5%	2359
	21st to end	Night	44% 3 10% 21% 16% 6%	1980
March	1st to 10th	Night	42% 4 8% 24% 13% 10%	5374
	11th to 20th	Night	38% 4 13% 25% 15% 5%	5008
	21st to end	Night	43% 4 8% 16% 24% 5%	5106
April	1st to 10th	Night	45% 4 9% 19% 19% 4	2000
	11th to 20th	Night	42% 5% 9% 20% 19% 4	1975
	21st to end	Night	40% 5% 9% 20% 21% 5%	2000
May	1st to 10th	Night	51% 6% 12% 17% 11% 2	4204
	11th to 20th	Night	52% 6% 10% 19% 12% 1	3589
	21st to end	Night	45% 6% 12% 21% 14% 2	3927
June	1st to 10th	Night	39% 6% 11% 22% 20% 2	1600
	11th to 20th	Night	39% 8% 13% 26% 12% 2	1600
	21st to end	Night	35% 8% 15% 24% 16% 2	1600
July	1st to 10th	Night	43% 8% 15% 20% 12% 1	3560
	11th to 20th	Night	46% 8% 20% 19% 7% 1	3552
	21st to end	Night	38% 6% 13% 24% 19% 1	3892
August	1st to 10th	Night	48% 7% 18% 18% 9% 1	2904
	11th to 20th	Night	40% 6% 12% 28% 13% 1	3227
	21st to end	Night	32% 5% 10% 29% 21% 2	3586
September	1st to 10th	Night	38% 6% 12% 20% 21% 3	2000
	11th to 20th	Night	31% 4 10% 26% 25% 4	2045
	21st to end	Night	44% 5% 9% 21% 19% 2	2200
October	1st to 10th	Night	38% 5% 9% 23% 22% 3	3877
	11th to 20th	Night	25% 3 11% 25% 29% 6%	3899
	21st to end	Night	26% 3 11% 30% 24% 5%	4380
November	1st to 10th	Night	33% 4 11% 25% 22% 5%	2667
	11th to 20th	Night	39% 4 8% 21% 21% 6%	2730
	21st to end	Night	37% 5% 11% 26% 18% 2	2826
December	1st to 10th	Night	36% 4 12% 30% 15% 3	4720
	11th to 20th	Night	44% 3 11% 23% 15% 4	5348
	21st to end	Night	44% 4 11% 20% 18% 3	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	27% 30% 30% 10% 3	220
	11th to 20th	Day	33% 31% 27% 7% 1	242
	21st to end	Day	27% 35% 25% 10% 2 1	363
February	1st to 10th	Day	28% 32% 28% 10% 2	300
	11th to 20th	Day	36% 28% 27% 8% 1	476
	21st to end	Day	29% 29% 30% 9% 2	414
March	1st to 10th	Day	30% 26% 28% 14% 2	500
	11th to 20th	Day	26% 28% 30% 11% 3 2	500
	21st to end	Day	27% 27% 31% 10% 4 1	550
April	1st to 10th	Day	28% 31% 27% 10% 4 1	500
	11th to 20th	Day	24% 25% 32% 13% 4 1	492
	21st to end	Day	27% 22% 33% 12% 5% 1	500
May	1st to 10th	Day	33% 21% 25% 14% 5% 2	503
	11th to 20th	Day	23% 18% 35% 17% 5% 2	527
	21st to end	Day	19% 13% 27% 26% 12% 3	573
June	1st to 10th	Day	14% 16% 32% 25% 11% 2	530
	11th to 20th	Day	18% 14% 33% 22% 10% 2	530
	21st to end	Day	12% 12% 33% 28% 13% 3	530
July	1st to 10th	Day	12% 7% 27% 31% 18% 5%	525
	11th to 20th	Day	8% 5% 29% 33% 20% 5%	524
	21st to end	Day	12% 8% 28% 31% 16% 4	576
August	1st to 10th	Day	11% 8% 31% 31% 13% 6%	526
	11th to 20th	Day	15% 5% 22% 37% 16% 5%	519
	21st to end	Day	13% 8% 30% 26% 15% 8%	583
September	1st to 10th	Day	17% 12% 25% 24% 16% 7%	530
	11th to 20th	Day	15% 8% 28% 28% 13% 8%	530
	21st to end	Day	26% 12% 29% 21% 8% 4	530
October	1st to 10th	Day	23% 10% 28% 20% 13% 7%	530
	11th to 20th	Day	23% 18% 26% 21% 9% 3	530
	21st to end	Day	19% 21% 33% 16% 10% 2	539
November	1st to 10th	Day	18% 18% 33% 19% 10% 2	425
	11th to 20th	Day	23% 25% 29% 18% 5%	430
	21st to end	Day	21% 25% 30% 19% 5% 1	330
December	1st to 10th	Day	25% 33% 28% 10% 5%	220
	11th to 20th	Day	34% 23% 30% 10% 2	220
	21st to end	Day	31% 23% 26% 14% 5% 1	242
January	1st to 10th	Night	21% 27% 32% 17% 3	840
	11th to 20th	Night	26% 24% 29% 18% 3	840
	21st to end	Night	20% 24% 36% 18% 2	924
February	1st to 10th	Night	21% 21% 36% 20% 1	801
	11th to 20th	Night	29% 29% 29% 13% 1	783
	21st to end	Night	25% 25% 31% 18% 1	660
March	1st to 10th	Night	22% 25% 30% 18% 4	800
	11th to 20th	Night	22% 26% 31% 16% 6% 1	800
	21st to end	Night	22% 21% 38% 15% 4	880
April	1st to 10th	Night	23% 25% 32% 16% 4	800
	11th to 20th	Night	20% 20% 36% 21% 4	791
	21st to end	Night	21% 19% 33% 24% 4	800
May	1st to 10th	Night	21% 15% 37% 21% 6%	666
	11th to 20th	Night	20% 14% 37% 24% 5%	407
	21st to end	Night	21% 8% 24% 36% 9% 1	433
June	1st to 10th	Night	17% 7% 31% 36% 10%	400
	11th to 20th	Night	14% 7% 32% 37% 11%	400
	21st to end	Night	11% 5% 33% 43% 9%	400
July	1st to 10th	Night	9% 3 32% 41% 15% 1	390
	11th to 20th	Night	10% 4 24% 43% 17% 2	388
	21st to end	Night	10% 5% 29% 37% 18%	472
August	1st to 10th	Night	13% 3 22% 39% 22% 2	597
	11th to 20th	Night	14% 5% 22% 39% 19% 2	790
	21st to end	Night	13% 4 24% 37% 20% 3	880
September	1st to 10th	Night	17% 6% 28% 34% 14% 3	800
	11th to 20th	Night	14% 6% 23% 34% 20% 4	800
	21st to end	Night	23% 7% 26% 27% 15% 1	800
October	1st to 10th	Night	20% 10% 25% 27% 16% 3	800
	11th to 20th	Night	19% 15% 28% 27% 11% 1	800
	21st to end	Night	19% 18% 33% 22% 8%	880
November	1st to 10th	Night	15% 16% 33% 25% 10%	820
	11th to 20th	Night	20% 20% 29% 23% 7%	840
	21st to end	Night	18% 21% 33% 20% 7% 1	840
December	1st to 10th	Night	25% 20% 31% 17% 7% 1	840
	11th to 20th	Night	20% 23% 31% 21% 5%	840
	21st to end	Night	22% 22% 31% 23% 2	924

Page generated at 2026-01-29 01:21:44. Version ac07

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