Navarro Mills Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Navarro Mills Lake clear sky chart from 2005-11-06 to 2024-08-30.

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	12% 6% 2 5% 4 4 4 3 5% 7% 49%	95566
	Night	11% 5% 2 5% 3 3 3 3 5% 7% 54%	93539
Transparency	Day	34% 6% 11% 22% 20% 7%	95342
	Night	31% 5% 10% 22% 22% 10%	93369
Seeing	Day	12% 6% 21% 28% 25% 9%	14858
	Night	12% 6% 27% 35% 18% 2	24680

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	12% 5% 2 5% 3 3 2 2 4 6% 56%	2847
	11th to 20th	Day	14% 5% 1 3 2 2 3 3 4 6% 57%	2850
	21st to end	Day	23% 9% 2 5% 2 2 2 2 3 4 46%	3135
February	1st to 10th	Day	18% 7% 3 6% 3 3 2 3 4 5% 45%	1844
	11th to 20th	Day	17% 10% 2 5% 3 3 4 2 4 4 46%	1849
	21st to end	Day	19% 6% 3 5% 3 3 3 2 4 5% 48%	1615
March	1st to 10th	Day	16% 9% 2 5% 4 4 3 3 5% 6% 44%	3436
	11th to 20th	Day	17% 8% 2 6% 5% 4 5% 4 5% 6% 39%	3480
	21st to end	Day	15% 6% 2 6% 4 4 4 4 5% 7% 41%	3814
April	1st to 10th	Day	14% 7% 2 5% 4 4 4 3 5% 7% 45%	2090
	11th to 20th	Day	14% 6% 2 6% 4 4 4 4 6% 7% 41%	2154
	21st to end	Day	13% 5% 3 5% 4 4 3 3 5% 7% 49%	2370
May	1st to 10th	Day	19% 8% 3 7% 4 4 4 4 6% 8% 34%	4082
	11th to 20th	Day	14% 7% 2 5% 4 3 4 3 5% 6% 47%	4082
	21st to end	Day	12% 6% 3 7% 5% 5% 5% 5% 7% 8% 36%	4477
June	1st to 10th	Day	6% 3 1 4 4 4 5% 4 7% 9% 52%	2470
	11th to 20th	Day	5% 3 1 4 5% 4 6% 4 7% 10% 51%	2470
	21st to end	Day	4 4 2 3 4 5% 5% 5% 7% 10% 51%	2470
July	1st to 10th	Day	6% 4 2 5% 4 4 5% 5% 7% 9% 49%	4120
	11th to 20th	Day	3 3 1 3 3 4 4 3 6% 10% 60%	4120
	21st to end	Day	7% 7% 2 6% 5% 5% 6% 5% 7% 8% 40%	4465
August	1st to 10th	Day	3 2 1 2 2 3 3 3 5% 10% 67%	2458
	11th to 20th	Day	6% 3 1 4 3 4 4 4 7% 10% 54%	2431
	21st to end	Day	5% 3 1 5% 4 5% 6% 4 7% 9% 51%	2385
September	1st to 10th	Day	9% 4 1 5% 4 5% 4 4 5% 7% 51%	1980
	11th to 20th	Day	11% 4 2 6% 4 4 5% 4 6% 8% 47%	1980
	21st to end	Day	7% 3 2 4 4 4 3 3 5% 7% 59%	1980
October	1st to 10th	Day	5% 4 1 3 3 3 4 3 5% 5% 63%	1934
	11th to 20th	Day	12% 4 1 4 2 3 3 2 4 6% 58%	1800
	21st to end	Day	14% 5% 1 5% 2 2 3 2 3 4 61%	1980
November	1st to 10th	Day	13% 6% 2 4 3 3 3 3 5% 6% 53%	1858
	11th to 20th	Day	8% 5% 2 5% 3 3 3 3 6% 6% 55%	1824
	21st to end	Day	17% 6% 2 5% 3 3 3 3 3 5% 49%	1710
December	1st to 10th	Day	14% 6% 2 4 3 3 3 4 4 5% 50%	1710
	11th to 20th	Day	16% 6% 3 6% 4 3 4 3 4 5% 47%	2161
	21st to end	Day	15% 8% 2 5% 4 3 3 2 3 5% 51%	3135
January	1st to 10th	Night	15% 5% 2 3 2 2 2 2 3 5% 58%	4108
	11th to 20th	Night	14% 4 1 3 2 2 3 2 3 4 62%	4120
	21st to end	Night	20% 6% 2 6% 3 3 3 3 3 6% 46%	4532
February	1st to 10th	Night	17% 6% 2 5% 3 3 3 3 5% 6% 48%	2352
	11th to 20th	Night	17% 6% 2 6% 3 3 3 2 4 5% 49%	2218
	21st to end	Night	18% 6% 2 4 3 2 3 3 4 5% 50%	1837
March	1st to 10th	Night	15% 8% 3 7% 4 4 4 3 5% 6% 41%	3419
	11th to 20th	Night	16% 6% 2 6% 3 4 5% 4 5% 6% 42%	3480
	21st to end	Night	13% 6% 2 6% 5% 4 3 3 5% 6% 48%	3817
April	1st to 10th	Night	9% 4 2 5% 4 3 3 4 5% 7% 53%	2090
	11th to 20th	Night	14% 5% 2 6% 4 3 4 3 5% 7% 48%	1972
	21st to end	Night	10% 5% 2 4 3 4 3 3 6% 7% 53%	1805
May	1st to 10th	Night	19% 8% 2 6% 4 3 3 2 5% 7% 40%	2823
	11th to 20th	Night	13% 6% 2 5% 4 3 4 3 5% 8% 47%	2823
	21st to end	Night	11% 5% 2 5% 4 4 5% 4 6% 9% 46%	3090
June	1st to 10th	Night	4 3 1 4 2 3 3 3 5% 10% 60%	1710
	11th to 20th	Night	3 3 1 2 3 3 3 3 5% 9% 65%	1710
	21st to end	Night	4 3 1 4 3 4 4 4 7% 9% 58%	1710
July	1st to 10th	Night	4 3 1 4 3 3 4 3 5% 9% 60%	2850
	11th to 20th	Night	3 2 1 3 2 2 3 3 5% 11% 65%	2850
	21st to end	Night	4 6% 2 5% 4 5% 5% 4 8% 10% 46%	3098
August	1st to 10th	Night	1 1 1 2 1 2 3 2 5% 10% 72%	1701
	11th to 20th	Night	5% 3 2 4 3 3 4 3 6% 11% 55%	1690
	21st to end	Night	3 3 1 4 3 4 4 4 6% 10% 58%	2173
September	1st to 10th	Night	7% 5% 1 3 3 4 4 3 4 7% 57%	1980
	11th to 20th	Night	10% 4 1 5% 3 3 3 4 5% 7% 54%	1980
	21st to end	Night	7% 3 1 4 2 2 3 3 5% 7% 64%	1980
October	1st to 10th	Night	4 4 1 4 2 2 3 2 4 7% 66%	2006
	11th to 20th	Night	12% 4 1 3 2 3 2 3 4 5% 61%	2160
	21st to end	Night	14% 4 2 3 3 2 3 2 3 4 62%	2376
November	1st to 10th	Night	11% 4 1 4 2 3 3 3 3 5% 61%	2220
	11th to 20th	Night	7% 4 2 5% 4 3 4 3 4 5% 59%	2351
	21st to end	Night	16% 6% 1 4 3 3 3 2 4 5% 52%	2470
December	1st to 10th	Night	13% 6% 2 4 3 3 3 3 4 6% 54%	2470
	11th to 20th	Night	14% 7% 3 6% 4 3 3 3 4 6% 49%	3036
	21st to end	Night	16% 6% 2 5% 3 2 2 2 3 4 55%	4532

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	31% 4 6% 20% 33% 7%	2848
	11th to 20th	Day	30% 3 8% 23% 28% 8%	2850
	21st to end	Day	45% 3 4 17% 23% 10%	3135
February	1st to 10th	Day	42% 4 5% 16% 21% 12%	1844
	11th to 20th	Day	43% 3 6% 16% 20% 11%	1859
	21st to end	Day	40% 3 6% 16% 20% 16%	1615
March	1st to 10th	Day	40% 5% 7% 15% 24% 8%	3436
	11th to 20th	Day	45% 7% 10% 17% 16% 5%	3480
	21st to end	Day	40% 7% 11% 18% 19% 6%	3814
April	1st to 10th	Day	38% 6% 9% 19% 17% 11%	2090
	11th to 20th	Day	41% 7% 9% 15% 20% 9%	2154
	21st to end	Day	35% 5% 10% 20% 23% 7%	2370
May	1st to 10th	Day	48% 7% 10% 19% 11% 4	4120
	11th to 20th	Day	39% 5% 9% 20% 26% 1	4086
	21st to end	Day	42% 10% 13% 21% 11% 4	4489
June	1st to 10th	Day	27% 7% 15% 31% 17% 3	2470
	11th to 20th	Day	26% 8% 13% 29% 17% 6%	2470
	21st to end	Day	25% 8% 14% 27% 22% 4	2470
July	1st to 10th	Day	29% 7% 23% 31% 10% 1	4056
	11th to 20th	Day	19% 5% 15% 39% 19% 3	4051
	21st to end	Day	38% 7% 15% 29% 11%	4325
August	1st to 10th	Day	13% 6% 17% 38% 24% 2	2444
	11th to 20th	Day	24% 8% 17% 30% 17% 3	2431
	21st to end	Day	26% 9% 16% 29% 16% 3	2385
September	1st to 10th	Day	32% 6% 12% 21% 19% 10%	1980
	11th to 20th	Day	33% 8% 13% 20% 17% 8%	1980
	21st to end	Day	26% 4 9% 25% 23% 14%	1980
October	1st to 10th	Day	22% 5% 12% 23% 21% 17%	1934
	11th to 20th	Day	28% 5% 7% 15% 27% 19%	1800
	21st to end	Day	30% 4 5% 16% 27% 18%	1980
November	1st to 10th	Day	32% 4 9% 21% 23% 10%	1858
	11th to 20th	Day	29% 5% 10% 17% 26% 13%	1824
	21st to end	Day	39% 4 6% 19% 21% 11%	1710
December	1st to 10th	Day	36% 4 10% 20% 21% 8%	1710
	11th to 20th	Day	40% 5% 7% 14% 24% 10%	2159
	21st to end	Day	38% 3 6% 19% 24% 11%	3135
January	1st to 10th	Night	30% 3 5% 17% 33% 11%	4108
	11th to 20th	Night	28% 4 6% 17% 28% 16%	4120
	21st to end	Night	42% 3 5% 15% 24% 11%	4532
February	1st to 10th	Night	38% 4 8% 14% 21% 16%	2352
	11th to 20th	Night	38% 4 7% 15% 24% 11%	2218
	21st to end	Night	38% 4 8% 14% 20% 17%	1837
March	1st to 10th	Night	42% 6% 9% 11% 21% 11%	3419
	11th to 20th	Night	41% 7% 9% 19% 16% 7%	3480
	21st to end	Night	37% 5% 10% 18% 24% 7%	3817
April	1st to 10th	Night	30% 5% 10% 21% 20% 14%	2090
	11th to 20th	Night	35% 6% 10% 17% 18% 14%	1972
	21st to end	Night	31% 6% 10% 18% 28% 7%	1805
May	1st to 10th	Night	43% 6% 10% 21% 14% 5%	2850
	11th to 20th	Night	35% 7% 13% 18% 24% 3	2824
	21st to end	Night	33% 8% 14% 29% 11% 6%	3099
June	1st to 10th	Night	20% 7% 15% 34% 20% 4	1710
	11th to 20th	Night	17% 6% 15% 34% 20% 8%	1710
	21st to end	Night	22% 8% 13% 27% 25% 5%	1710
July	1st to 10th	Night	22% 5% 18% 44% 9% 1	2805
	11th to 20th	Night	15% 4 18% 42% 18% 4	2796
	21st to end	Night	29% 8% 20% 32% 10% 1	2999
August	1st to 10th	Night	9% 4 17% 38% 27% 4	1691
	11th to 20th	Night	23% 6% 17% 29% 19% 5%	1690
	21st to end	Night	20% 8% 18% 33% 17% 3	2173
September	1st to 10th	Night	27% 6% 12% 24% 21% 9%	1980
	11th to 20th	Night	28% 7% 14% 21% 21% 9%	1980
	21st to end	Night	20% 4 11% 23% 25% 16%	1980
October	1st to 10th	Night	20% 4 11% 27% 21% 18%	2006
	11th to 20th	Night	27% 4 7% 16% 25% 21%	2160
	21st to end	Night	29% 3 6% 16% 25% 21%	2376
November	1st to 10th	Night	28% 4 7% 20% 26% 15%	2220
	11th to 20th	Night	28% 5% 7% 20% 26% 15%	2351
	21st to end	Night	36% 3 8% 16% 24% 13%	2470
December	1st to 10th	Night	32% 4 10% 22% 21% 12%	2470
	11th to 20th	Night	38% 4 5% 14% 25% 14%	3037
	21st to end	Night	35% 3 5% 16% 26% 15%	4532

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	19% 14% 33% 25% 9% 1	270
	11th to 20th	Day	18% 14% 36% 23% 8% 1	270
	21st to end	Day	22% 10% 40% 19% 9% 1	297
February	1st to 10th	Day	24% 11% 35% 23% 7%	270
	11th to 20th	Day	26% 15% 36% 17% 6%	270
	21st to end	Day	27% 15% 40% 16% 3	225
March	1st to 10th	Day	21% 11% 40% 20% 7% 1	270
	11th to 20th	Day	19% 15% 39% 20% 5% 1	270
	21st to end	Day	15% 11% 44% 24% 5% 1	297
April	1st to 10th	Day	19% 13% 39% 21% 8%	270
	11th to 20th	Day	21% 11% 35% 24% 9% 1	352
	21st to end	Day	16% 11% 37% 25% 10% 1	550
May	1st to 10th	Day	12% 11% 35% 33% 8% 1	653
	11th to 20th	Day	16% 6% 26% 32% 18% 4	675
	21st to end	Day	13% 5% 26% 32% 19% 4	734
June	1st to 10th	Day	6% 3 14% 39% 27% 11%	680
	11th to 20th	Day	5% 15% 44% 27% 8%	680
	21st to end	Day	3 2 11% 33% 38% 14%	680
July	1st to 10th	Day	6% 2 8% 32% 39% 13%	671
	11th to 20th	Day	2 4 32% 47% 15%	668
	21st to end	Day	4 1 4 28% 47% 15%	739
August	1st to 10th	Day	3 4 26% 49% 18%	676
	11th to 20th	Day	7% 1 3 27% 47% 16%	665
	21st to end	Day	7% 2 3 19% 39% 30%	432
September	1st to 10th	Day	9% 1 16% 41% 33%	270
	11th to 20th	Day	5% 1 4 22% 43% 24%	270
	21st to end	Day	11% 3 4 20% 40% 23%	270
October	1st to 10th	Day	3 4 13% 27% 37% 16%	270
	11th to 20th	Day	9% 6% 27% 27% 21% 10%	270
	21st to end	Day	22% 11% 22% 22% 16% 7%	297
November	1st to 10th	Day	19% 2 30% 29% 14% 6%	270
	11th to 20th	Day	13% 8% 24% 33% 19% 3	270
	21st to end	Day	23% 8% 30% 25% 12% 1	270
December	1st to 10th	Day	17% 8% 31% 25% 15% 3	270
	11th to 20th	Day	23% 12% 29% 28% 7% 2	270
	21st to end	Day	21% 7% 38% 24% 9% 1	297
January	1st to 10th	Night	15% 10% 36% 30% 8% 1	950
	11th to 20th	Night	19% 11% 33% 30% 6%	950
	21st to end	Night	16% 10% 35% 33% 6%	1045
February	1st to 10th	Night	20% 11% 35% 30% 4	832
	11th to 20th	Night	20% 11% 40% 26% 3	744
	21st to end	Night	22% 11% 43% 21% 3	581
March	1st to 10th	Night	17% 12% 38% 26% 6%	570
	11th to 20th	Night	14% 8% 39% 32% 7%	570
	21st to end	Night	12% 12% 41% 30% 4	627
April	1st to 10th	Night	10% 11% 44% 30% 5%	570
	11th to 20th	Night	14% 10% 41% 26% 7%	563
	21st to end	Night	11% 9% 44% 26% 10% 1	570
May	1st to 10th	Night	11% 9% 39% 33% 8% 1	570
	11th to 20th	Night	13% 3 32% 36% 15% 1	561
	21st to end	Night	9% 4 29% 40% 16% 1	617
June	1st to 10th	Night	5% 2 17% 44% 30% 2	570
	11th to 20th	Night	5% 1 20% 52% 21% 1	570
	21st to end	Night	3 2 13% 42% 36% 5%	570
July	1st to 10th	Night	4 1 8% 44% 39% 4	555
	11th to 20th	Night	2 1 7% 47% 39% 4	552
	21st to end	Night	2 1 6% 45% 43% 4	624
August	1st to 10th	Night	1 4 44% 47% 4	567
	11th to 20th	Night	7% 1 4 44% 39% 5%	564
	21st to end	Night	4 5% 36% 48% 8%	624
September	1st to 10th	Night	9% 1 6% 40% 38% 6%	540
	11th to 20th	Night	12% 1 7% 33% 45% 3	540
	21st to end	Night	7% 1 11% 37% 38% 6%	540
October	1st to 10th	Night	6% 1 15% 47% 25% 5%	566
	11th to 20th	Night	14% 3 23% 38% 18% 3	720
	21st to end	Night	16% 7% 27% 32% 17% 2	792
November	1st to 10th	Night	12% 3 26% 39% 18% 1	740
	11th to 20th	Night	8% 8% 30% 41% 14%	831
	21st to end	Night	18% 9% 30% 31% 12% 1	950
December	1st to 10th	Night	16% 7% 34% 33% 9% 1	950
	11th to 20th	Night	21% 8% 29% 36% 6%	950
	21st to end	Night	18% 9% 33% 33% 7%	1045

Page generated at 2024-08-27 08:49:43. Version ac07

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