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 2025-02-06.

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% 50%	109045
	Night	12% 5% 2 4 3 3 3 3 4 7% 55%	109426
Transparency	Day	33% 5% 10% 23% 21% 8%	112788
	Night	30% 4 9% 22% 23% 12%	113810
Seeing	Day	12% 6% 21% 28% 25% 9%	15338
	Night	12% 6% 27% 35% 17% 2	25356

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	13% 7% 3 5% 3 3 3 2 4 5% 52%	4077
	11th to 20th	Day	11% 5% 1 4 2 2 2 2 4 6% 60%	4080
	21st to end	Day	25% 9% 3 5% 2 2 2 2 3 3 45%	4488
February	1st to 10th	Day	18% 7% 3 6% 3 3 2 3 4 5% 46%	1892
	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	2 1 1 2 2 2 3 5% 9% 74%	4104
	11th to 20th	Day	4 2 1 3 2 2 3 3 6% 9% 66%	4041
	21st to end	Day	4 2 1 4 3 4 5% 5% 8% 11% 53%	4001
September	1st to 10th	Day	9% 5% 2 5% 5% 5% 4 4 5% 7% 50%	2090
	11th to 20th	Day	11% 4 2 6% 4 4 5% 4 6% 8% 48%	2090
	21st to end	Day	7% 3 2 4 4 4 3 3 5% 7% 59%	2090
October	1st to 10th	Day	5% 4 1 3 3 3 4 3 5% 5% 65%	2041
	11th to 20th	Day	12% 4 1 4 2 3 3 2 4 6% 60%	1900
	21st to end	Day	13% 5% 1 4 2 2 3 2 3 4 61%	2090
November	1st to 10th	Day	14% 6% 2 5% 3 3 3 3 5% 6% 52%	1958
	11th to 20th	Day	8% 5% 2 5% 3 3 3 3 6% 6% 56%	1920
	21st to end	Day	16% 6% 2 5% 3 3 3 3 3 5% 50%	1800
December	1st to 10th	Day	18% 6% 2 3 3 3 3 3 5% 5% 48%	2940
	11th to 20th	Day	17% 7% 3 7% 4 4 4 3 4 5% 44%	3391
	21st to end	Day	14% 8% 2 6% 4 3 3 2 3 4 50%	4488
January	1st to 10th	Night	16% 6% 2 4 2 3 2 2 3 4 56%	5888
	11th to 20th	Night	10% 3 1 2 2 2 2 1 3 6% 67%	5900
	21st to end	Night	26% 7% 2 5% 3 3 2 2 3 5% 43%	6490
February	1st to 10th	Night	16% 6% 2 5% 2 3 3 3 5% 6% 49%	2415
	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 1 2 1 4 7% 81%	2836
	11th to 20th	Night	3 2 1 2 2 2 3 3 6% 12% 63%	2798
	21st to end	Night	2 2 1 3 3 3 4 4 6% 11% 62%	3650
September	1st to 10th	Night	7% 5% 1 4 3 4 4 3 4 7% 57%	2090
	11th to 20th	Night	10% 4 1 5% 3 3 3 4 5% 7% 55%	2090
	21st to end	Night	7% 3 1 4 2 2 3 3 4 8% 64%	2090
October	1st to 10th	Night	4 4 1 3 2 2 3 2 4 7% 67%	2118
	11th to 20th	Night	11% 4 1 3 2 3 2 2 4 5% 63%	2280
	21st to end	Night	13% 4 2 3 3 2 3 2 3 4 62%	2508
November	1st to 10th	Night	12% 4 1 4 3 3 3 3 3 5% 59%	2340
	11th to 20th	Night	7% 4 2 5% 4 3 4 3 4 5% 60%	2475
	21st to end	Night	15% 6% 1 4 3 3 3 2 4 5% 53%	2600
December	1st to 10th	Night	19% 6% 2 5% 3 2 2 2 3 5% 50%	4250
	11th to 20th	Night	17% 9% 3 6% 3 2 3 2 3 4 48%	4816
	21st to end	Night	14% 6% 2 6% 3 2 3 2 3 4 55%	6490

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	35% 3 6% 24% 26% 5%	4078
	11th to 20th	Day	27% 2 6% 22% 31% 12%	4080
	21st to end	Day	47% 2 3 13% 20% 14%	4488
February	1st to 10th	Day	41% 4 5% 16% 22% 12%	1892
	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	10% 4 12% 36% 34% 4	4090
	11th to 20th	Day	16% 5% 17% 41% 20% 2	4080
	21st to end	Day	22% 8% 23% 30% 15% 2	4000
September	1st to 10th	Day	32% 6% 12% 20% 19% 11%	2090
	11th to 20th	Day	33% 8% 12% 20% 19% 8%	2090
	21st to end	Day	25% 4 9% 24% 23% 15%	2090
October	1st to 10th	Day	13% 3 7% 13% 29% 36%	3392
	11th to 20th	Day	16% 3 5% 20% 32% 24%	3140
	21st to end	Day	25% 4 4 25% 32% 11%	3428
November	1st to 10th	Day	34% 4 9% 20% 22% 10%	1958
	11th to 20th	Day	28% 5% 10% 17% 26% 15%	1920
	21st to end	Day	38% 4 6% 19% 22% 11%	1800
December	1st to 10th	Day	38% 3 8% 21% 23% 6%	2940
	11th to 20th	Day	43% 4 6% 11% 26% 10%	3389
	21st to end	Day	39% 3 5% 18% 26% 9%	4488
January	1st to 10th	Night	34% 3 5% 22% 29% 8%	5888
	11th to 20th	Night	22% 3 5% 18% 36% 17%	5900
	21st to end	Night	47% 3 4 13% 19% 15%	6490
February	1st to 10th	Night	37% 4 8% 14% 21% 16%	2415
	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	6% 3 12% 35% 40% 5%	2826
	11th to 20th	Night	15% 4 18% 41% 18% 3	2825
	21st to end	Night	17% 7% 24% 34% 17% 2	3650
September	1st to 10th	Night	28% 6% 12% 23% 20% 10%	2090
	11th to 20th	Night	28% 6% 13% 21% 22% 10%	2090
	21st to end	Night	20% 4 10% 23% 26% 17%	2090
October	1st to 10th	Night	12% 2 6% 15% 22% 43%	3534
	11th to 20th	Night	16% 2 4 19% 32% 27%	3779
	21st to end	Night	22% 3 4 20% 35% 17%	4120
November	1st to 10th	Night	29% 4 7% 19% 25% 15%	2340
	11th to 20th	Night	27% 4 7% 20% 26% 16%	2475
	21st to end	Night	35% 3 8% 17% 24% 13%	2600
December	1st to 10th	Night	38% 3 6% 19% 24% 10%	4250
	11th to 20th	Night	42% 3 5% 12% 25% 13%	4817
	21st to end	Night	35% 3 4 18% 27% 13%	6490

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% 34% 23% 9% 1	300
	11th to 20th	Day	17% 14% 37% 24% 8% 1	300
	21st to end	Day	23% 11% 39% 19% 8% 1	330
February	1st to 10th	Day	23% 11% 34% 25% 7%	285
	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%	438
September	1st to 10th	Day	8% 1 2 20% 39% 30%	300
	11th to 20th	Day	5% 1 4 22% 43% 24%	300
	21st to end	Day	11% 2 5% 22% 38% 22%	300
October	1st to 10th	Day	2 4 12% 28% 37% 16%	300
	11th to 20th	Day	8% 5% 26% 30% 22% 9%	300
	21st to end	Day	20% 11% 21% 23% 18% 6%	330
November	1st to 10th	Day	20% 4 28% 29% 13% 6%	300
	11th to 20th	Day	12% 8% 25% 32% 19% 4	300
	21st to end	Day	21% 9% 31% 24% 13% 2	300
December	1st to 10th	Day	18% 8% 31% 26% 14% 3	300
	11th to 20th	Day	22% 12% 29% 29% 6% 2	300
	21st to end	Day	21% 7% 38% 24% 9% 1	330
January	1st to 10th	Night	16% 10% 36% 30% 8% 1	1000
	11th to 20th	Night	18% 12% 34% 30% 6%	1000
	21st to end	Night	18% 10% 35% 32% 5%	1100
February	1st to 10th	Night	19% 11% 36% 30% 4	855
	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% 7%	627
September	1st to 10th	Night	9% 1 7% 41% 37% 5%	570
	11th to 20th	Night	12% 1 6% 34% 43% 3	570
	21st to end	Night	7% 1 10% 38% 37% 6%	570
October	1st to 10th	Night	6% 1 14% 47% 26% 5%	598
	11th to 20th	Night	14% 3 23% 38% 18% 3	760
	21st to end	Night	15% 7% 27% 32% 17% 2	836
November	1st to 10th	Night	13% 4 25% 39% 17% 1	780
	11th to 20th	Night	8% 7% 30% 40% 13%	875
	21st to end	Night	17% 9% 31% 30% 12% 1	1000
December	1st to 10th	Night	16% 7% 35% 33% 9% 1	1000
	11th to 20th	Night	21% 9% 29% 35% 6%	1000
	21st to end	Night	18% 8% 33% 33% 7%	1100

Page generated at 2025-02-03 02:05:49. Version ac07

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