NOVAC Turner Mountain
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the NOVAC Turner Mountain clear sky chart from 2005-11-06 to 2024-11-10.

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% 6% 2 6% 4 4 5% 4 6% 8% 41%	101257
	Night	15% 7% 2 6% 4 4 4 3 5% 7% 43%	97859
Transparency	Day	38% 7% 12% 24% 15% 3	104899
	Night	38% 7% 12% 23% 17% 3	102356
Seeing	Day	18% 13% 26% 24% 14% 5%	14998
	Night	17% 11% 29% 29% 12% 1	24556

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	18% 4 2 5% 4 4 4 4 4 6% 46%	2677
	11th to 20th	Day	15% 10% 3 8% 5% 4 4 3 4 5% 39%	2840
	21st to end	Day	18% 9% 3 7% 5% 4 4 4 5% 6% 37%	3124
February	1st to 10th	Day	14% 7% 3 6% 6% 5% 5% 4 6% 5% 39%	1710
	11th to 20th	Day	17% 8% 2 5% 5% 4 4 4 6% 6% 40%	1686
	21st to end	Day	18% 8% 2 6% 5% 5% 3 3 5% 6% 40%	1571
March	1st to 10th	Day	21% 8% 2 6% 5% 5% 4 3 4 6% 36%	3435
	11th to 20th	Day	10% 5% 2 5% 4 4 5% 4 5% 7% 49%	3480
	21st to end	Day	20% 7% 2 6% 4 4 4 3 5% 7% 39%	3836
April	1st to 10th	Day	12% 6% 3 6% 4 5% 5% 4 6% 7% 42%	2280
	11th to 20th	Day	14% 6% 2 6% 4 3 4 3 5% 6% 47%	2254
	21st to end	Day	19% 6% 2 6% 4 4 4 4 5% 6% 40%	2280
May	1st to 10th	Day	21% 8% 3 6% 4 4 5% 4 5% 8% 30%	4077
	11th to 20th	Day	23% 6% 3 6% 5% 4 4 4 6% 9% 31%	4198
	21st to end	Day	11% 5% 2 5% 4 4 5% 4 7% 10% 44%	4823
June	1st to 10th	Day	11% 4 2 5% 5% 4 5% 5% 7% 9% 43%	2660
	11th to 20th	Day	11% 5% 3 6% 4 4 5% 5% 8% 9% 41%	2660
	21st to end	Day	8% 4 2 5% 5% 4 5% 5% 7% 11% 44%	2660
July	1st to 10th	Day	6% 4 2 7% 5% 5% 5% 6% 8% 10% 43%	4440
	11th to 20th	Day	9% 5% 2 5% 5% 5% 6% 5% 8% 12% 39%	4194
	21st to end	Day	11% 7% 3 7% 6% 6% 6% 4 7% 8% 36%	4466
August	1st to 10th	Day	15% 5% 2 6% 5% 5% 5% 5% 7% 10% 33%	4104
	11th to 20th	Day	9% 4 2 6% 5% 5% 7% 5% 7% 9% 41%	3921
	21st to end	Day	11% 4 2 5% 4 4 5% 4 6% 8% 49%	4180
September	1st to 10th	Day	14% 6% 3 5% 5% 4 4 4 4 7% 46%	2280
	11th to 20th	Day	13% 6% 1 6% 4 3 4 3 5% 7% 48%	2273
	21st to end	Day	22% 7% 2 5% 4 4 3 4 5% 6% 38%	1986
October	1st to 10th	Day	17% 5% 2 5% 3 4 3 3 5% 6% 47%	1900
	11th to 20th	Day	16% 4 2 5% 4 4 4 3 4 5% 50%	1900
	21st to end	Day	14% 5% 2 4 3 3 3 2 5% 5% 51%	2090
November	1st to 10th	Day	13% 5% 2 4 4 3 3 3 5% 8% 51%	1892
	11th to 20th	Day	14% 6% 2 4 4 4 4 3 5% 5% 50%	1658
	21st to end	Day	15% 5% 2 3 4 4 4 4 5% 7% 47%	1520
December	1st to 10th	Day	15% 7% 3 6% 4 3 4 4 6% 7% 40%	1520
	11th to 20th	Day	16% 6% 2 6% 4 3 4 3 4 8% 44%	1910
	21st to end	Day	18% 6% 2 6% 5% 4 5% 4 6% 8% 35%	2772
January	1st to 10th	Night	13% 7% 2 5% 4 3 3 3 5% 6% 48%	4267
	11th to 20th	Night	18% 8% 2 4 3 3 3 3 4 5% 47%	4120
	21st to end	Night	20% 8% 3 5% 3 3 3 3 4 6% 41%	4532
February	1st to 10th	Night	14% 7% 2 6% 5% 5% 5% 4 6% 5% 40%	2470
	11th to 20th	Night	18% 7% 2 5% 4 3 4 3 4 6% 43%	2380
	21st to end	Night	17% 9% 2 6% 4 4 4 3 5% 6% 41%	1879
March	1st to 10th	Night	20% 7% 2 6% 3 4 5% 4 5% 6% 38%	3418
	11th to 20th	Night	11% 6% 2 4 4 3 4 3 5% 7% 50%	3480
	21st to end	Night	14% 8% 3 6% 4 3 3 3 5% 5% 47%	3796
April	1st to 10th	Night	15% 8% 2 6% 4 4 4 4 6% 6% 41%	1900
	11th to 20th	Night	13% 6% 2 5% 4 5% 3 4 5% 7% 46%	1875
	21st to end	Night	17% 5% 2 4 4 4 5% 4 6% 7% 43%	1900
May	1st to 10th	Night	23% 9% 3 6% 5% 4 5% 4 5% 8% 30%	2846
	11th to 20th	Night	24% 9% 3 7% 4 3 4 3 4 7% 31%	2693
	21st to end	Night	11% 5% 2 5% 4 5% 4 4 6% 10% 44%	2732
June	1st to 10th	Night	10% 5% 3 5% 4 4 5% 4 7% 8% 45%	1520
	11th to 20th	Night	11% 6% 3 6% 4 4 5% 4 6% 8% 43%	1520
	21st to end	Night	8% 5% 1 6% 5% 4 6% 3 8% 10% 44%	1520
July	1st to 10th	Night	8% 5% 2 7% 4 5% 6% 4 8% 10% 41%	2520
	11th to 20th	Night	7% 5% 2 7% 6% 5% 6% 5% 7% 11% 38%	2762
	21st to end	Night	10% 8% 3 7% 5% 5% 5% 5% 8% 8% 37%	3087
August	1st to 10th	Night	16% 5% 3 7% 5% 5% 6% 4 7% 9% 32%	2825
	11th to 20th	Night	9% 7% 3 8% 6% 6% 6% 4 6% 8% 38%	2876
	21st to end	Night	12% 5% 2 5% 3 4 4 3 6% 8% 49%	3476
September	1st to 10th	Night	14% 6% 2 6% 4 4 5% 4 6% 5% 45%	1900
	11th to 20th	Night	11% 6% 3 5% 4 4 3 3 4 7% 49%	1904
	21st to end	Night	21% 7% 3 5% 4 4 3 3 4 5% 40%	2194
October	1st to 10th	Night	19% 6% 2 5% 3 3 3 3 4 4 47%	2280
	11th to 20th	Night	14% 5% 2 4 3 3 3 3 4 5% 52%	2280
	21st to end	Night	14% 5% 2 4 3 4 3 2 5% 6% 51%	2508
November	1st to 10th	Night	11% 6% 2 5% 4 3 3 3 4 5% 54%	2390
	11th to 20th	Night	14% 7% 2 4 4 3 3 3 5% 6% 50%	2520
	21st to end	Night	14% 5% 1 5% 4 4 4 4 5% 7% 48%	2660
December	1st to 10th	Night	17% 7% 3 6% 3 4 4 3 5% 6% 42%	2660
	11th to 20th	Night	17% 6% 2 6% 4 4 4 3 4 7% 43%	3285
	21st to end	Night	17% 7% 3 6% 4 4 5% 4 6% 8% 36%	4884

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% 6% 8% 30% 14% 4	2678
	11th to 20th	Day	44% 6% 10% 19% 15% 6%	2840
	21st to end	Day	47% 7% 10% 22% 12% 2	3124
February	1st to 10th	Day	43% 7% 12% 23% 12% 3	1710
	11th to 20th	Day	43% 5% 9% 23% 16% 3	1695
	21st to end	Day	46% 6% 12% 19% 15% 4	1571
March	1st to 10th	Day	48% 6% 10% 21% 12% 4	3435
	11th to 20th	Day	31% 7% 10% 27% 21% 4	3480
	21st to end	Day	44% 6% 11% 20% 15% 3	3836
April	1st to 10th	Day	39% 7% 12% 19% 18% 5%	2280
	11th to 20th	Day	36% 6% 12% 21% 20% 6%	2254
	21st to end	Day	43% 7% 10% 21% 14% 4	2280
May	1st to 10th	Day	48% 10% 11% 19% 10% 1	4115
	11th to 20th	Day	48% 9% 13% 22% 8% 1	4202
	21st to end	Day	32% 10% 16% 23% 17% 2	4837
June	1st to 10th	Day	35% 9% 15% 24% 16% 1	2660
	11th to 20th	Day	36% 11% 15% 24% 13% 2	2660
	21st to end	Day	31% 11% 16% 25% 16% 2	2660
July	1st to 10th	Day	33% 11% 19% 22% 11% 5%	4370
	11th to 20th	Day	35% 9% 16% 28% 10% 1	4122
	21st to end	Day	43% 8% 10% 21% 17% 1	4324
August	1st to 10th	Day	43% 9% 18% 23% 7%	4091
	11th to 20th	Day	35% 10% 14% 27% 14% 1	3960
	21st to end	Day	33% 7% 15% 27% 16% 2	4180
September	1st to 10th	Day	38% 7% 12% 18% 20% 5%	2280
	11th to 20th	Day	34% 6% 10% 27% 20% 3	2273
	21st to end	Day	45% 7% 10% 20% 16% 2	1986
October	1st to 10th	Day	37% 4 8% 18% 28% 5%	3160
	11th to 20th	Day	26% 4 7% 29% 24% 10%	3140
	21st to end	Day	22% 3 11% 30% 27% 8%	3428
November	1st to 10th	Day	33% 4 12% 25% 22% 5%	1892
	11th to 20th	Day	35% 5% 12% 22% 21% 6%	1658
	21st to end	Day	37% 6% 11% 27% 17% 2	1520
December	1st to 10th	Day	41% 7% 12% 25% 12% 3	1520
	11th to 20th	Day	39% 4 11% 31% 11% 4	1906
	21st to end	Day	41% 9% 14% 25% 10% 1	2772
January	1st to 10th	Night	36% 5% 11% 27% 18% 4	4267
	11th to 20th	Night	40% 5% 10% 23% 19% 4	4120
	21st to end	Night	44% 5% 10% 25% 15% 1	4532
February	1st to 10th	Night	42% 6% 13% 23% 14% 2	2470
	11th to 20th	Night	43% 5% 10% 21% 16% 5%	2382
	21st to end	Night	43% 6% 11% 20% 15% 5%	1879
March	1st to 10th	Night	44% 8% 10% 24% 12% 2	3418
	11th to 20th	Night	31% 7% 11% 25% 23% 4	3480
	21st to end	Night	38% 5% 10% 23% 19% 5%	3796
April	1st to 10th	Night	41% 7% 9% 20% 19% 4	1900
	11th to 20th	Night	35% 7% 12% 21% 19% 6%	1875
	21st to end	Night	38% 8% 12% 25% 13% 5%	1900
May	1st to 10th	Night	50% 9% 11% 18% 10% 3	2873
	11th to 20th	Night	51% 8% 12% 19% 9% 1	2694
	21st to end	Night	32% 11% 17% 25% 12% 3	2739
June	1st to 10th	Night	34% 9% 14% 24% 17% 2	1520
	11th to 20th	Night	36% 10% 14% 24% 14% 2	1520
	21st to end	Night	33% 8% 17% 22% 17% 3	1520
July	1st to 10th	Night	36% 10% 20% 17% 13% 4	2480
	11th to 20th	Night	37% 10% 19% 23% 10% 1	2711
	21st to end	Night	40% 9% 15% 20% 15% 1	2988
August	1st to 10th	Night	45% 9% 15% 23% 7% 1	2814
	11th to 20th	Night	41% 7% 12% 24% 14% 1	2903
	21st to end	Night	33% 7% 13% 30% 16% 2	3476
September	1st to 10th	Night	39% 7% 10% 20% 19% 5%	1900
	11th to 20th	Night	35% 5% 10% 27% 21% 3	1904
	21st to end	Night	46% 6% 10% 20% 16% 3	2194
October	1st to 10th	Night	40% 4 10% 20% 21% 4	3800
	11th to 20th	Night	24% 4 11% 23% 31% 8%	3779
	21st to end	Night	23% 4 10% 31% 25% 7%	4120
November	1st to 10th	Night	32% 4 11% 25% 22% 6%	2390
	11th to 20th	Night	35% 5% 8% 24% 22% 6%	2520
	21st to end	Night	35% 5% 12% 24% 20% 4	2660
December	1st to 10th	Night	43% 5% 11% 24% 14% 3	2660
	11th to 20th	Night	40% 5% 10% 23% 17% 4	3288
	21st to end	Night	40% 10% 16% 20% 12% 1	4884

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	28% 27% 28% 15% 2	225
	11th to 20th	Day	31% 26% 27% 15% 1	270
	21st to end	Day	22% 31% 31% 12% 3 1	297
February	1st to 10th	Day	19% 28% 36% 13% 4	270
	11th to 20th	Day	35% 26% 32% 5% 2	293
	21st to end	Day	29% 22% 30% 16% 2	382
March	1st to 10th	Day	24% 23% 29% 21% 3	460
	11th to 20th	Day	24% 24% 30% 16% 5% 2	460
	21st to end	Day	21% 21% 33% 19% 5% 1	506
April	1st to 10th	Day	20% 26% 27% 20% 6% 1	460
	11th to 20th	Day	16% 20% 29% 20% 13% 3	452
	21st to end	Day	23% 16% 32% 18% 10% 2	460
May	1st to 10th	Day	22% 17% 28% 19% 10% 4	463
	11th to 20th	Day	21% 10% 30% 21% 14% 4	487
	21st to end	Day	19% 6% 24% 26% 19% 6%	529
June	1st to 10th	Day	11% 8% 27% 29% 19% 5%	490
	11th to 20th	Day	12% 8% 28% 30% 16% 6%	490
	21st to end	Day	10% 6% 28% 32% 18% 6%	490
July	1st to 10th	Day	12% 4 17% 31% 24% 11%	485
	11th to 20th	Day	5% 3 21% 34% 28% 9%	484
	21st to end	Day	12% 4 20% 33% 23% 8%	532
August	1st to 10th	Day	13% 4 20% 25% 27% 11%	486
	11th to 20th	Day	13% 4 19% 32% 22% 11%	479
	21st to end	Day	9% 3 19% 33% 23% 13%	539
September	1st to 10th	Day	16% 7% 20% 25% 19% 12%	490
	11th to 20th	Day	14% 5% 20% 29% 20% 12%	490
	21st to end	Day	28% 11% 20% 24% 14% 3	490
October	1st to 10th	Day	21% 7% 20% 26% 19% 7%	490
	11th to 20th	Day	17% 15% 23% 28% 14% 2	490
	21st to end	Day	16% 11% 35% 25% 11% 3	539
November	1st to 10th	Day	15% 14% 33% 26% 9% 3	464
	11th to 20th	Day	19% 15% 34% 21% 10% 2	318
	21st to end	Day	19% 22% 31% 20% 7% 1	180
December	1st to 10th	Day	17% 22% 37% 19% 4 1	180
	11th to 20th	Day	22% 24% 28% 21% 6%	180
	21st to end	Day	23% 21% 31% 18% 7% 1	198
January	1st to 10th	Night	20% 20% 39% 18% 3	760
	11th to 20th	Night	22% 16% 33% 25% 4	760
	21st to end	Night	19% 17% 43% 20% 2	836
February	1st to 10th	Night	19% 15% 39% 24% 3	760
	11th to 20th	Night	24% 21% 37% 16% 2	743
	21st to end	Night	25% 17% 38% 17% 3	628
March	1st to 10th	Night	19% 19% 37% 22% 3	760
	11th to 20th	Night	23% 19% 32% 21% 5% 1	760
	21st to end	Night	19% 17% 39% 20% 4	836
April	1st to 10th	Night	18% 20% 36% 22% 4	760
	11th to 20th	Night	16% 13% 35% 27% 8% 1	751
	21st to end	Night	19% 11% 33% 29% 8%	760
May	1st to 10th	Night	22% 8% 26% 32% 12% 1	590
	11th to 20th	Night	20% 6% 27% 34% 12% 1	494
	21st to end	Night	15% 3 22% 39% 20% 1	411
June	1st to 10th	Night	9% 3 26% 41% 21%	380
	11th to 20th	Night	12% 4 23% 41% 19% 1	380
	21st to end	Night	9% 2 23% 49% 17% 1	380
July	1st to 10th	Night	12% 3 18% 38% 26% 4	370
	11th to 20th	Night	6% 1 14% 41% 35% 3	503
	21st to end	Night	9% 3 17% 40% 28% 3	624
August	1st to 10th	Night	11% 2 12% 41% 30% 3	567
	11th to 20th	Night	10% 3 15% 41% 29% 3	616
	21st to end	Night	11% 3 16% 41% 25% 4	836
September	1st to 10th	Night	17% 2 18% 32% 27% 4	760
	11th to 20th	Night	12% 4 18% 35% 28% 3	760
	21st to end	Night	24% 5% 21% 30% 19% 1	760
October	1st to 10th	Night	21% 5% 23% 29% 19% 4	760
	11th to 20th	Night	16% 11% 26% 33% 14% 1	760
	21st to end	Night	16% 12% 32% 28% 12%	836
November	1st to 10th	Night	14% 10% 34% 30% 11% 1	779
	11th to 20th	Night	17% 13% 33% 28% 8% 1	760
	21st to end	Night	16% 14% 33% 29% 8% 1	760
December	1st to 10th	Night	20% 17% 35% 22% 7%	760
	11th to 20th	Night	18% 12% 41% 24% 4	760
	21st to end	Night	20% 14% 33% 31% 3	836

Page generated at 2024-11-07 06:55:43. Version ac07

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