N Crow Rd
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the N Crow Rd clear sky chart from 2005-11-06 to 2025-03-12.

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	4 6% 2 6% 4 4 4 4 6% 8% 52%	112840
	Night	3 5% 2 5% 4 3 4 3 5% 7% 58%	115017
Transparency	Day	27% 8% 13% 23% 20% 8%	112581
	Night	23% 7% 14% 27% 22% 7%	114866
Seeing	Day	12% 22% 32% 22% 10% 2	16081
	Night	9% 25% 33% 24% 8% 1	26278

By Month

Percentage Cloud Cover SW (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	3 2 9% 5% 5% 4 3 5% 8% 55%	3638
	11th to 20th	Day	3 2 8% 6% 3 4 4 7% 9% 52%	3640
	21st to end	Day	1 4 2 5% 3 3 3 3 5% 9% 64%	4506
February	1st to 10th	Day	2 4 3 7% 6% 5% 4 4 6% 10% 50%	1800
	11th to 20th	Day	1 4 2 8% 5% 4 4 4 6% 8% 55%	1877
	21st to end	Day	1 6% 3 7% 3 3 4 3 5% 8% 57%	1650
March	1st to 10th	Day	2 8% 4 7% 3 3 3 3 6% 8% 54%	3230
	11th to 20th	Day	3 9% 4 8% 4 4 4 4 5% 7% 48%	3464
	21st to end	Day	3 9% 3 7% 5% 5% 5% 5% 7% 9% 42%	4057
April	1st to 10th	Day	5% 8% 2 5% 3 4 4 4 6% 8% 49%	2280
	11th to 20th	Day	8% 12% 4 7% 4 5% 4 3 5% 7% 41%	2251
	21st to end	Day	9% 10% 3 7% 5% 5% 5% 4 6% 7% 40%	2280
May	1st to 10th	Day	10% 13% 3 7% 5% 4 5% 4 5% 6% 38%	4173
	11th to 20th	Day	9% 8% 2 5% 5% 5% 6% 5% 7% 9% 39%	4388
	21st to end	Day	6% 7% 2 5% 5% 5% 5% 5% 7% 9% 44%	4825
June	1st to 10th	Day	5% 5% 2 5% 5% 5% 6% 6% 8% 9% 45%	2660
	11th to 20th	Day	7% 5% 2 5% 3 4 5% 5% 8% 7% 48%	2660
	21st to end	Day	4 4 1 4 5% 6% 5% 5% 7% 9% 51%	2660
July	1st to 10th	Day	6% 4 2 5% 4 4 5% 5% 7% 8% 51%	4430
	11th to 20th	Day	3 3 1 5% 5% 6% 7% 6% 7% 9% 48%	4430
	21st to end	Day	6% 3 2 5% 5% 5% 5% 5% 7% 8% 49%	4802
August	1st to 10th	Day	8% 5% 2 6% 4 5% 5% 5% 9% 10% 40%	4100
	11th to 20th	Day	5% 4 1 5% 5% 5% 5% 5% 7% 8% 50%	3799
	21st to end	Day	5% 4 2 5% 4 4 5% 4 6% 7% 54%	4180
September	1st to 10th	Day	5% 5% 1 5% 4 4 4 4 5% 7% 57%	2280
	11th to 20th	Day	7% 3 1 5% 3 4 4 3 4 7% 59%	2271
	21st to end	Day	6% 5% 2 4 3 3 3 2 4 6% 63%	2081
October	1st to 10th	Day	4 4 1 3 2 2 2 2 3 4 72%	3170
	11th to 20th	Day	4 5% 2 5% 3 4 3 3 5% 7% 59%	3150
	21st to end	Day	4 7% 2 4 3 2 3 3 5% 7% 60%	3282
November	1st to 10th	Day	3 5% 1 4 2 3 3 3 6% 7% 62%	1763
	11th to 20th	Day	2 6% 2 4 3 3 3 3 5% 9% 61%	1800
	21st to end	Day	2 5% 2 6% 4 4 4 3 6% 7% 56%	1613
December	1st to 10th	Day	1 3 1 2 2 3 3 3 4 6% 72%	2620
	11th to 20th	Day	1 5% 2 4 3 3 4 3 6% 9% 61%	3026
	21st to end	Day	1 5% 3 7% 5% 5% 4 3 6% 7% 54%	4004
January	1st to 10th	Night	5% 3 8% 5% 4 4 4 6% 7% 54%	6327
	11th to 20th	Night	2 2 7% 4 4 3 3 5% 8% 62%	6340
	21st to end	Night	1 5% 2 6% 3 3 3 3 4 6% 64%	6514
February	1st to 10th	Night	1 5% 2 5% 5% 4 5% 4 6% 8% 57%	2600
	11th to 20th	Night	1 6% 2 5% 5% 4 4 3 5% 8% 57%	2410
	21st to end	Night	1 8% 3 6% 3 3 3 2 5% 6% 60%	1980
March	1st to 10th	Night	1 7% 3 6% 3 3 4 3 5% 8% 57%	3854
	11th to 20th	Night	3 10% 4 6% 3 3 3 2 4 7% 55%	3540
	21st to end	Night	3 8% 3 7% 4 4 4 4 7% 7% 49%	3587
April	1st to 10th	Night	4 8% 1 4 4 5% 4 3 5% 7% 54%	1900
	11th to 20th	Night	6% 10% 3 6% 4 3 3 3 5% 7% 51%	1877
	21st to end	Night	9% 10% 3 5% 3 3 3 3 4 7% 49%	1900
May	1st to 10th	Night	7% 10% 3 5% 5% 4 4 4 6% 6% 45%	2777
	11th to 20th	Night	9% 7% 1 4 4 4 6% 4 6% 9% 46%	2517
	21st to end	Night	6% 6% 2 4 3 4 3 4 5% 7% 54%	2762
June	1st to 10th	Night	4 5% 1 3 3 4 4 5% 7% 10% 53%	1520
	11th to 20th	Night	6% 3 1 3 4 3 3 4 5% 8% 59%	1520
	21st to end	Night	5% 4 1 3 3 4 3 3 5% 8% 62%	1520
July	1st to 10th	Night	4 3 1 5% 4 4 5% 4 6% 8% 57%	2540
	11th to 20th	Night	3 2 1 5% 3 4 5% 6% 8% 10% 53%	2540
	21st to end	Night	3 3 1 4 4 4 5% 5% 6% 9% 57%	2761
August	1st to 10th	Night	9% 5% 2 5% 3 3 5% 4 7% 10% 49%	2836
	11th to 20th	Night	4 3 1 5% 4 4 5% 5% 7% 9% 52%	3038
	21st to end	Night	3 3 1 4 4 4 4 4 5% 10% 58%	3487
September	1st to 10th	Night	7% 5% 1 4 3 3 3 3 6% 6% 60%	1900
	11th to 20th	Night	5% 3 1 4 3 3 3 3 6% 7% 63%	1909
	21st to end	Night	7% 4 1 4 3 2 3 3 4 6% 63%	2095
October	1st to 10th	Night	4 3 1 2 2 2 3 2 4 4 73%	3800
	11th to 20th	Night	4 6% 2 4 3 3 4 3 5% 8% 58%	3778
	21st to end	Night	3 5% 2 5% 3 3 3 3 4 6% 62%	4243
November	1st to 10th	Night	3 4 2 4 3 3 3 3 6% 8% 63%	2535
	11th to 20th	Night	2 5% 2 3 3 2 3 4 5% 8% 63%	2600
	21st to end	Night	2 5% 2 5% 4 3 4 3 7% 7% 59%	2785
December	1st to 10th	Night	3 2 3 2 2 3 2 4 6% 74%	4570
	11th to 20th	Night	1 4 2 5% 2 2 3 2 5% 9% 66%	5181
	21st to end	Night	1 5% 3 6% 4 4 4 4 6% 8% 55%	6974

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	25% 8% 18% 25% 20% 5%	3639
	11th to 20th	Day	25% 9% 18% 21% 23% 5%	3640
	21st to end	Day	17% 7% 16% 27% 25% 8%	4506
February	1st to 10th	Day	29% 10% 20% 21% 15% 5%	1800
	11th to 20th	Day	26% 9% 15% 27% 17% 5%	1886
	21st to end	Day	24% 7% 18% 26% 19% 7%	1650
March	1st to 10th	Day	25% 8% 14% 26% 22% 6%	3230
	11th to 20th	Day	31% 12% 17% 28% 10% 2	3464
	21st to end	Day	35% 11% 14% 30% 8% 1	4057
April	1st to 10th	Day	30% 9% 16% 24% 15% 6%	2280
	11th to 20th	Day	40% 8% 15% 19% 14% 3	2254
	21st to end	Day	40% 10% 11% 24% 14% 1	2280
May	1st to 10th	Day	43% 9% 11% 19% 13% 5%	4173
	11th to 20th	Day	34% 12% 14% 23% 14% 2	4392
	21st to end	Day	31% 10% 15% 22% 19% 4	4825
June	1st to 10th	Day	30% 11% 17% 20% 17% 5%	2660
	11th to 20th	Day	30% 9% 10% 18% 22% 11%	2660
	21st to end	Day	25% 9% 12% 22% 19% 13%	2660
July	1st to 10th	Day	26% 8% 10% 12% 24% 20%	4361
	11th to 20th	Day	25% 10% 11% 18% 19% 18%	4355
	21st to end	Day	27% 8% 9% 18% 22% 17%	4651
August	1st to 10th	Day	32% 10% 14% 20% 15% 9%	4085
	11th to 20th	Day	28% 7% 11% 15% 23% 14%	3836
	21st to end	Day	26% 6% 12% 16% 27% 14%	4179
September	1st to 10th	Day	25% 6% 8% 18% 28% 15%	2280
	11th to 20th	Day	23% 6% 10% 22% 26% 12%	2271
	21st to end	Day	23% 5% 8% 21% 34% 8%	2081
October	1st to 10th	Day	17% 4 6% 16% 31% 25%	3170
	11th to 20th	Day	24% 5% 11% 33% 20% 7%	3150
	21st to end	Day	24% 5% 9% 32% 25% 4	3282
November	1st to 10th	Day	20% 8% 15% 25% 28% 5%	1763
	11th to 20th	Day	20% 6% 15% 29% 24% 5%	1800
	21st to end	Day	24% 7% 16% 26% 21% 6%	1613
December	1st to 10th	Day	14% 7% 12% 35% 27% 5%	2620
	11th to 20th	Day	19% 7% 16% 38% 19% 2	3024
	21st to end	Day	27% 8% 16% 25% 18% 7%	4004
January	1st to 10th	Night	27% 6% 16% 26% 17% 7%	6327
	11th to 20th	Night	22% 8% 16% 21% 26% 8%	6340
	21st to end	Night	20% 7% 15% 24% 24% 9%	6514
February	1st to 10th	Night	24% 9% 21% 26% 16% 4	2600
	11th to 20th	Night	26% 9% 16% 27% 18% 3	2411
	21st to end	Night	25% 6% 14% 24% 23% 8%	1980
March	1st to 10th	Night	24% 8% 14% 27% 21% 6%	3854
	11th to 20th	Night	28% 8% 15% 27% 20% 2	3540
	21st to end	Night	30% 10% 16% 32% 10% 1	3587
April	1st to 10th	Night	29% 9% 14% 25% 18% 6%	1900
	11th to 20th	Night	32% 8% 15% 26% 15% 4	1877
	21st to end	Night	36% 7% 11% 28% 18% 1	1900
May	1st to 10th	Night	34% 9% 13% 24% 15% 5%	2777
	11th to 20th	Night	30% 11% 18% 27% 11% 3	2518
	21st to end	Night	27% 8% 17% 26% 19% 3	2762
June	1st to 10th	Night	22% 10% 23% 27% 14% 5%	1520
	11th to 20th	Night	22% 7% 13% 24% 22% 12%	1520
	21st to end	Night	20% 7% 10% 26% 24% 13%	1520
July	1st to 10th	Night	23% 6% 10% 21% 25% 14%	2500
	11th to 20th	Night	20% 7% 14% 25% 21% 12%	2492
	21st to end	Night	20% 8% 13% 26% 20% 14%	2674
August	1st to 10th	Night	29% 7% 17% 22% 19% 5%	2828
	11th to 20th	Night	26% 7% 17% 21% 18% 12%	3067
	21st to end	Night	21% 5% 16% 20% 26% 11%	3487
September	1st to 10th	Night	24% 6% 8% 20% 26% 15%	1900
	11th to 20th	Night	21% 6% 9% 25% 26% 13%	1909
	21st to end	Night	22% 5% 8% 24% 33% 8%	2095
October	1st to 10th	Night	16% 4 7% 20% 34% 19%	3800
	11th to 20th	Night	24% 6% 10% 29% 25% 6%	3778
	21st to end	Night	22% 5% 10% 31% 26% 7%	4243
November	1st to 10th	Night	20% 8% 14% 26% 27% 6%	2535
	11th to 20th	Night	19% 7% 17% 29% 22% 7%	2600
	21st to end	Night	24% 6% 13% 29% 23% 6%	2785
December	1st to 10th	Night	13% 5% 14% 36% 26% 5%	4570
	11th to 20th	Night	16% 7% 15% 41% 19% 2	5182
	21st to end	Night	24% 8% 16% 27% 20% 5%	6974

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	15% 33% 31% 15% 4 2	300
	11th to 20th	Day	13% 47% 25% 13% 2	300
	21st to end	Day	12% 40% 37% 9% 2 1	330
February	1st to 10th	Day	20% 44% 29% 7% 1	300
	11th to 20th	Day	16% 41% 34% 8% 2	300
	21st to end	Day	21% 36% 32% 10%	249
March	1st to 10th	Day	10% 35% 38% 14% 4	300
	11th to 20th	Day	15% 27% 39% 14% 5%	440
	21st to end	Day	15% 31% 37% 13% 4	506
April	1st to 10th	Day	15% 33% 35% 14% 3	460
	11th to 20th	Day	23% 33% 30% 12% 2	452
	21st to end	Day	21% 23% 33% 16% 5% 2	460
May	1st to 10th	Day	19% 23% 31% 18% 7% 1	615
	11th to 20th	Day	18% 15% 32% 22% 11% 2	675
	21st to end	Day	10% 21% 29% 23% 15% 2	734
June	1st to 10th	Day	7% 10% 30% 32% 16% 5%	680
	11th to 20th	Day	10% 15% 37% 27% 10% 1	680
	21st to end	Day	6% 11% 36% 29% 15% 3	680
July	1st to 10th	Day	8% 7% 24% 31% 25% 5%	671
	11th to 20th	Day	4 5% 30% 37% 20% 4	668
	21st to end	Day	6% 5% 23% 33% 28% 5%	739
August	1st to 10th	Day	10% 6% 35% 29% 17% 3	495
	11th to 20th	Day	8% 7% 32% 34% 16% 4	477
	21st to end	Day	9% 10% 32% 31% 15% 3	539
September	1st to 10th	Day	7% 11% 32% 33% 13% 3	490
	11th to 20th	Day	7% 16% 33% 28% 13% 4	481
	21st to end	Day	9% 15% 32% 24% 14% 6%	300
October	1st to 10th	Day	10% 17% 31% 25% 11% 6%	300
	11th to 20th	Day	11% 27% 35% 18% 7% 1	300
	21st to end	Day	12% 31% 38% 15% 2 1	330
November	1st to 10th	Day	11% 31% 38% 13% 5% 2	300
	11th to 20th	Day	18% 34% 33% 12% 3	300
	21st to end	Day	15% 41% 32% 10% 2	300
December	1st to 10th	Day	17% 38% 32% 8% 5%	300
	11th to 20th	Day	19% 47% 26% 7%	300
	21st to end	Day	17% 47% 24% 9% 2 1	330
January	1st to 10th	Night	10% 41% 30% 13% 5% 1	1000
	11th to 20th	Night	11% 48% 26% 10% 4 1	1000
	21st to end	Night	7% 41% 36% 12% 4	900
February	1st to 10th	Night	9% 45% 33% 10% 3	800
	11th to 20th	Night	9% 38% 37% 15% 2	784
	21st to end	Night	13% 38% 38% 9% 1	660
March	1st to 10th	Night	6% 31% 42% 17% 4	800
	11th to 20th	Night	8% 24% 39% 23% 5%	766
	21st to end	Night	9% 26% 40% 20% 5% 1	698
April	1st to 10th	Night	11% 22% 41% 22% 3	570
	11th to 20th	Night	14% 21% 41% 19% 4 1	563
	21st to end	Night	16% 18% 32% 26% 8%	570
May	1st to 10th	Night	14% 16% 33% 26% 9% 1	570
	11th to 20th	Night	17% 8% 28% 34% 11% 1	561
	21st to end	Night	8% 12% 33% 29% 16% 1	617
June	1st to 10th	Night	6% 8% 30% 39% 15% 2	570
	11th to 20th	Night	7% 10% 36% 39% 8%	570
	21st to end	Night	5% 7% 31% 39% 16% 2	570
July	1st to 10th	Night	6% 4 22% 43% 24% 2	555
	11th to 20th	Night	3 2 23% 47% 22% 2	552
	21st to end	Night	4 3 19% 44% 28% 2	624
August	1st to 10th	Night	8% 2 22% 48% 19% 1	567
	11th to 20th	Night	4 3 24% 49% 19% 2	564
	21st to end	Night	4 4 27% 39% 25% 1	627
September	1st to 10th	Night	9% 5% 23% 41% 19% 3	570
	11th to 20th	Night	6% 7% 26% 41% 17% 3	570
	21st to end	Night	8% 8% 34% 36% 13% 1	575
October	1st to 10th	Night	9% 17% 32% 28% 11% 3	760
	11th to 20th	Night	7% 21% 38% 25% 8% 1	760
	21st to end	Night	9% 26% 40% 19% 5% 1	910
November	1st to 10th	Night	8% 26% 41% 21% 5% 1	975
	11th to 20th	Night	10% 36% 40% 12% 2 1	1000
	21st to end	Night	8% 35% 39% 15% 2	1000
December	1st to 10th	Night	13% 39% 33% 13% 2	1000
	11th to 20th	Night	10% 42% 33% 12% 2 1	1000
	21st to end	Night	12% 45% 29% 10% 3	1100

Page generated at 2025-03-09 06:08:42. Version ac07

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