ScrubGrass Campgrounds
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the ScrubGrass Campgrounds clear sky chart from 2005-11-06 to 2024-01-14.

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% 5% 2 5% 5% 3 5% 5% 5% 7% 45%	74677
	Night	12% 5% 2 4 4 2 4 4 5% 7% 50%	75082
Transparency	Day	25% 37% 7% 15% 13% 4	74401
	Night	23% 36% 6% 14% 15% 5%	74879
Seeing	Day	13% 7% 20% 25% 24% 11%	14117
	Night	14% 6% 23% 32% 21% 3	24007

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	19% 9% 2 5% 4 2 3 3 3 5% 45%	1707
	11th to 20th	Day	19% 8% 3 6% 4 2 3 4 4 5% 42%	1647
	21st to end	Day	16% 6% 3 4 4 2 3 3 4 4 50%	1782
February	1st to 10th	Day	19% 8% 3 4 4 2 4 4 4 5% 43%	1689
	11th to 20th	Day	22% 9% 3 6% 3 2 3 3 3 5% 41%	1748
	21st to end	Day	23% 9% 3 6% 5% 2 3 3 3 5% 38%	1480
March	1st to 10th	Day	17% 8% 3 6% 5% 3 4 4 4 5% 41%	1921
	11th to 20th	Day	17% 7% 3 7% 6% 3 4 4 4 5% 39%	1980
	21st to end	Day	14% 7% 3 6% 5% 3 5% 3 5% 7% 41%	2245
April	1st to 10th	Day	13% 4 3 6% 5% 3 4 5% 5% 7% 45%	2160
	11th to 20th	Day	15% 6% 3 5% 4 2 3 4 5% 6% 47%	2134
	21st to end	Day	11% 6% 3 6% 6% 3 4 4 5% 6% 45%	2160
May	1st to 10th	Day	14% 6% 3 5% 5% 3 5% 4 5% 6% 44%	2160
	11th to 20th	Day	11% 5% 3 6% 6% 3 5% 5% 7% 9% 40%	2124
	21st to end	Day	8% 4 2 6% 7% 4 6% 6% 7% 9% 40%	2639
June	1st to 10th	Day	8% 4 3 5% 6% 4 7% 6% 6% 9% 43%	2520
	11th to 20th	Day	5% 3 2 5% 5% 3 6% 5% 6% 10% 49%	2520
	21st to end	Day	5% 3 2 4 5% 3 6% 6% 7% 10% 50%	2520
July	1st to 10th	Day	7% 4 2 5% 5% 5% 7% 8% 9% 12% 36%	2365
	11th to 20th	Day	7% 4 2 5% 6% 4 6% 6% 8% 11% 41%	2340
	21st to end	Day	7% 4 2 5% 6% 4 7% 7% 8% 9% 43%	2546
August	1st to 10th	Day	5% 3 2 5% 6% 4 5% 7% 8% 11% 44%	2216
	11th to 20th	Day	9% 4 2 5% 6% 4 5% 6% 6% 9% 43%	2125
	21st to end	Day	10% 4 2 4 5% 3 5% 6% 7% 9% 45%	2376
September	1st to 10th	Day	8% 4 2 6% 5% 5% 5% 6% 5% 8% 46%	2160
	11th to 20th	Day	11% 4 3 5% 5% 3 4 6% 5% 7% 47%	2160
	21st to end	Day	10% 4 1 3 4 3 4 4 4 7% 56%	1949
October	1st to 10th	Day	7% 3 1 3 4 3 3 5% 5% 8% 56%	1800
	11th to 20th	Day	13% 4 2 5% 3 2 2 3 5% 6% 57%	1800
	21st to end	Day	18% 6% 2 3 2 3 2 4 4 4 51%	1980
November	1st to 10th	Day	12% 3 2 3 3 2 3 2 3 5% 60%	1858
	11th to 20th	Day	11% 5% 2 4 5% 2 4 4 4 6% 53%	1715
	21st to end	Day	19% 7% 3 5% 4 2 3 3 4 6% 45%	1710
December	1st to 10th	Day	19% 9% 3 5% 4 3 4 4 3 5% 42%	1644
	11th to 20th	Day	15% 8% 3 6% 5% 3 4 3 4 6% 43%	1918
	21st to end	Day	13% 7% 3 6% 7% 4 6% 5% 5% 5% 38%	2879
January	1st to 10th	Night	18% 7% 2 4 4 2 3 3 4 6% 48%	2458
	11th to 20th	Night	19% 8% 3 5% 4 2 3 3 4 5% 43%	2386
	21st to end	Night	18% 6% 3 5% 3 2 3 3 5% 5% 48%	2574
February	1st to 10th	Night	20% 7% 3 5% 4 3 3 3 3 4 43%	2268
	11th to 20th	Night	19% 7% 3 4 4 2 4 4 4 5% 44%	2098
	21st to end	Night	23% 6% 2 5% 4 2 3 3 3 5% 41%	1776
March	1st to 10th	Night	16% 6% 2 4 5% 3 4 4 5% 6% 46%	2052
	11th to 20th	Night	17% 6% 3 6% 5% 3 4 5% 4 7% 41%	1980
	21st to end	Night	17% 6% 2 5% 4 2 4 4 5% 6% 45%	2111
April	1st to 10th	Night	11% 3 3 5% 5% 3 4 4 6% 7% 49%	1800
	11th to 20th	Night	13% 5% 2 5% 4 2 4 4 5% 7% 49%	1775
	21st to end	Night	11% 4 3 5% 5% 2 4 3 5% 7% 51%	1800
May	1st to 10th	Night	12% 4 2 4 3 3 3 5% 5% 8% 51%	1800
	11th to 20th	Night	11% 5% 2 4 4 2 4 6% 5% 9% 46%	1769
	21st to end	Night	6% 4 3 4 4 3 6% 5% 6% 11% 48%	1629
June	1st to 10th	Night	5% 3 2 4 5% 3 5% 4 6% 11% 50%	1440
	11th to 20th	Night	3 2 2 3 3 2 4 5% 6% 11% 57%	1440
	21st to end	Night	4 2 2 3 4 3 5% 4 6% 9% 58%	1440
July	1st to 10th	Night	4 3 2 4 5% 3 6% 6% 8% 10% 49%	1589
	11th to 20th	Night	6% 3 2 3 5% 3 5% 6% 7% 10% 50%	1620
	21st to end	Night	3 3 2 3 3 3 4 7% 8% 12% 52%	1772
August	1st to 10th	Night	3 4 1 2 5% 3 4 6% 7% 11% 55%	1720
	11th to 20th	Night	5% 5% 2 4 5% 3 5% 5% 6% 11% 48%	1776
	21st to end	Night	8% 4 2 4 5% 2 4 6% 6% 10% 51%	1980
September	1st to 10th	Night	8% 4 2 4 5% 3 4 5% 4 7% 54%	1800
	11th to 20th	Night	10% 5% 2 4 5% 3 5% 5% 5% 5% 52%	1800
	21st to end	Night	9% 4 2 3 3 2 3 3 4 7% 59%	1987
October	1st to 10th	Night	7% 2 1 3 3 2 3 3 5% 6% 64%	2160
	11th to 20th	Night	11% 4 2 4 3 2 3 3 5% 6% 58%	2160
	21st to end	Night	16% 5% 1 4 3 2 3 3 3 5% 55%	2376
November	1st to 10th	Night	11% 4 2 4 4 2 3 3 4 5% 59%	2220
	11th to 20th	Night	11% 4 3 4 4 2 3 3 3 7% 56%	2462
	21st to end	Night	14% 5% 3 4 5% 2 3 4 4 5% 51%	2470
December	1st to 10th	Night	17% 7% 3 5% 4 2 4 4 5% 6% 45%	2531
	11th to 20th	Night	16% 6% 2 5% 5% 3 3 3 4 4 49%	3279
	21st to end	Night	15% 7% 3 6% 5% 3 5% 4 5% 5% 42%	4784

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	28% 38% 5% 15% 12% 2	1708
	11th to 20th	Day	27% 40% 4 16% 13% 1	1647
	21st to end	Day	29% 36% 4 13% 16% 2	1782
February	1st to 10th	Day	30% 36% 5% 14% 13% 3	1689
	11th to 20th	Day	31% 35% 3 12% 14% 5%	1758
	21st to end	Day	32% 35% 3 13% 13% 4	1480
March	1st to 10th	Day	28% 35% 6% 12% 13% 6%	1921
	11th to 20th	Day	33% 38% 5% 12% 10% 2	1980
	21st to end	Day	30% 36% 7% 15% 10% 2	2245
April	1st to 10th	Day	24% 36% 8% 14% 15% 3	2160
	11th to 20th	Day	23% 36% 6% 13% 17% 5%	2134
	21st to end	Day	26% 37% 6% 14% 15% 1	2160
May	1st to 10th	Day	32% 37% 7% 13% 9% 2	2160
	11th to 20th	Day	24% 38% 10% 16% 11% 2	2128
	21st to end	Day	24% 39% 10% 18% 8%	2639
June	1st to 10th	Day	24% 38% 9% 17% 11% 1	2520
	11th to 20th	Day	18% 37% 7% 19% 15% 4	2520
	21st to end	Day	17% 38% 9% 16% 15% 5%	2520
July	1st to 10th	Day	23% 40% 12% 14% 9% 2	2301
	11th to 20th	Day	24% 40% 11% 14% 6% 4	2271
	21st to end	Day	22% 40% 13% 17% 7%	2405
August	1st to 10th	Day	19% 39% 13% 21% 8%	2202
	11th to 20th	Day	23% 37% 10% 18% 10% 3	2125
	21st to end	Day	22% 38% 10% 16% 11% 3	2376
September	1st to 10th	Day	26% 38% 6% 11% 13% 6%	2160
	11th to 20th	Day	27% 37% 6% 9% 14% 6%	2160
	21st to end	Day	19% 35% 5% 12% 20% 9%	1949
October	1st to 10th	Day	16% 36% 5% 15% 18% 9%	1800
	11th to 20th	Day	21% 35% 4 12% 21% 7%	1800
	21st to end	Day	23% 37% 4 14% 16% 6%	1980
November	1st to 10th	Day	13% 39% 5% 16% 20% 6%	1858
	11th to 20th	Day	21% 39% 4 13% 17% 6%	1715
	21st to end	Day	26% 38% 5% 13% 13% 5%	1710
December	1st to 10th	Day	29% 39% 6% 11% 12% 3	1644
	11th to 20th	Day	30% 32% 4 13% 20% 2	1915
	21st to end	Day	34% 26% 6% 16% 14% 3	2879
January	1st to 10th	Night	26% 38% 5% 13% 16% 2	2458
	11th to 20th	Night	26% 41% 4 14% 14% 2	2386
	21st to end	Night	29% 37% 3 12% 16% 3	2574
February	1st to 10th	Night	30% 35% 4 13% 14% 4	2268
	11th to 20th	Night	29% 36% 3 12% 14% 5%	2099
	21st to end	Night	30% 35% 4 10% 15% 5%	1776
March	1st to 10th	Night	25% 36% 5% 13% 13% 8%	2052
	11th to 20th	Night	28% 38% 8% 11% 10% 4	1980
	21st to end	Night	30% 35% 5% 15% 12% 3	2111
April	1st to 10th	Night	22% 37% 6% 16% 14% 6%	1800
	11th to 20th	Night	21% 34% 5% 13% 18% 8%	1775
	21st to end	Night	24% 36% 5% 18% 15% 2	1800
May	1st to 10th	Night	25% 37% 8% 16% 11% 4	1800
	11th to 20th	Night	24% 38% 8% 17% 13% 1	1770
	21st to end	Night	18% 38% 12% 18% 12% 1	1630
June	1st to 10th	Night	19% 38% 9% 19% 14% 1	1440
	11th to 20th	Night	13% 37% 7% 21% 17% 4	1440
	21st to end	Night	14% 38% 9% 19% 17% 4	1440
July	1st to 10th	Night	19% 40% 13% 16% 9% 3	1544
	11th to 20th	Night	18% 40% 15% 13% 10% 4	1566
	21st to end	Night	15% 41% 13% 22% 8%	1673
August	1st to 10th	Night	14% 37% 13% 23% 12% 1	1710
	11th to 20th	Night	20% 37% 11% 17% 12% 4	1776
	21st to end	Night	18% 38% 11% 17% 13% 4	1980
September	1st to 10th	Night	23% 37% 7% 11% 15% 7%	1800
	11th to 20th	Night	24% 38% 6% 9% 17% 6%	1800
	21st to end	Night	18% 36% 4 12% 20% 10%	1987
October	1st to 10th	Night	15% 35% 4 16% 19% 12%	2160
	11th to 20th	Night	19% 36% 5% 11% 19% 10%	2160
	21st to end	Night	22% 36% 4 13% 19% 6%	2376
November	1st to 10th	Night	13% 39% 4 15% 21% 7%	2220
	11th to 20th	Night	20% 39% 5% 12% 18% 7%	2462
	21st to end	Night	25% 39% 4 10% 17% 5%	2470
December	1st to 10th	Night	25% 39% 5% 13% 13% 4	2531
	11th to 20th	Night	27% 33% 4 14% 18% 3	3281
	21st to end	Night	32% 26% 5% 16% 18% 3	4784

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	21% 15% 40% 17% 6% 1	270
	11th to 20th	Day	24% 14% 39% 17% 4 2	249
	21st to end	Day	17% 16% 45% 17% 6%	264
February	1st to 10th	Day	22% 14% 35% 22% 5% 2	240
	11th to 20th	Day	33% 18% 33% 14% 3	240
	21st to end	Day	34% 18% 30% 13% 5%	198
March	1st to 10th	Day	21% 15% 35% 19% 8% 1	240
	11th to 20th	Day	18% 23% 32% 23% 4	240
	21st to end	Day	15% 20% 35% 20% 11%	331
April	1st to 10th	Day	16% 11% 37% 28% 9%	420
	11th to 20th	Day	20% 13% 26% 27% 12% 3	412
	21st to end	Day	15% 11% 30% 26% 16% 2	420
May	1st to 10th	Day	15% 11% 25% 31% 16% 2	423
	11th to 20th	Day	13% 5% 24% 24% 26% 8%	447
	21st to end	Day	9% 3 17% 33% 27% 11%	659
June	1st to 10th	Day	10% 3 13% 28% 30% 17%	630
	11th to 20th	Day	4 2 11% 33% 36% 14%	630
	21st to end	Day	6% 2 10% 33% 30% 18%	630
July	1st to 10th	Day	7% 1 7% 24% 40% 21%	621
	11th to 20th	Day	6% 1 6% 25% 36% 26%	618
	21st to end	Day	5% 2 5% 22% 40% 26%	684
August	1st to 10th	Day	6% 2 7% 21% 42% 22%	514
	11th to 20th	Day	12% 2 5% 20% 42% 19%	439
	21st to end	Day	13% 1 5% 16% 37% 28%	495
September	1st to 10th	Day	7% 2 8% 24% 39% 21%	450
	11th to 20th	Day	10% 2 10% 23% 32% 23%	450
	21st to end	Day	14% 2 11% 25% 32% 17%	419
October	1st to 10th	Day	9% 2 21% 25% 31% 12%	270
	11th to 20th	Day	9% 6% 31% 34% 15% 5%	270
	21st to end	Day	21% 9% 27% 26% 14% 3	297
November	1st to 10th	Day	18% 5% 24% 31% 20% 3	270
	11th to 20th	Day	10% 13% 33% 31% 11% 1	270
	21st to end	Day	23% 11% 26% 23% 13% 3	270
December	1st to 10th	Day	20% 18% 31% 21% 9% 1	270
	11th to 20th	Day	23% 12% 30% 21% 13% 1	270
	21st to end	Day	22% 19% 33% 22% 4 1	297
January	1st to 10th	Night	21% 10% 33% 31% 5%	950
	11th to 20th	Night	22% 10% 35% 26% 6% 1	918
	21st to end	Night	20% 10% 37% 30% 4	990
February	1st to 10th	Night	24% 11% 35% 24% 5%	828
	11th to 20th	Night	22% 12% 34% 29% 3	703
	21st to end	Night	24% 14% 33% 25% 3	592
March	1st to 10th	Night	19% 10% 31% 33% 7%	612
	11th to 20th	Night	19% 10% 31% 32% 9% 1	540
	21st to end	Night	20% 8% 29% 32% 11%	594
April	1st to 10th	Night	13% 9% 34% 35% 8% 1	540
	11th to 20th	Night	15% 9% 29% 34% 12% 1	533
	21st to end	Night	13% 8% 31% 34% 13% 1	540
May	1st to 10th	Night	13% 5% 21% 44% 15% 1	540
	11th to 20th	Night	12% 3 24% 37% 20% 2	531
	21st to end	Night	6% 2 15% 39% 31% 6%	584
June	1st to 10th	Night	6% 3 10% 37% 38% 6%	540
	11th to 20th	Night	4 1 9% 37% 43% 6%	540
	21st to end	Night	5% 1 6% 35% 43% 10%	540
July	1st to 10th	Night	3 1 4 32% 50% 10%	525
	11th to 20th	Night	4 2 5% 25% 54% 11%	522
	21st to end	Night	4 4 30% 51% 11%	591
August	1st to 10th	Night	4 1 4 26% 53% 12%	537
	11th to 20th	Night	7% 2 4 32% 47% 9%	534
	21st to end	Night	9% 1 5% 24% 49% 11%	594
September	1st to 10th	Night	9% 1 7% 34% 43% 8%	540
	11th to 20th	Night	10% 2 9% 29% 43% 8%	540
	21st to end	Night	11% 2 12% 33% 36% 6%	701
October	1st to 10th	Night	8% 2 14% 35% 35% 6%	720
	11th to 20th	Night	12% 5% 23% 41% 18% 1	720
	21st to end	Night	17% 6% 22% 34% 19% 2	792
November	1st to 10th	Night	12% 5% 23% 37% 21% 2	740
	11th to 20th	Night	13% 6% 32% 36% 13% 1	760
	21st to end	Night	15% 8% 31% 32% 13% 2	760
December	1st to 10th	Night	20% 10% 30% 33% 8%	821
	11th to 20th	Night	23% 8% 28% 34% 7%	950
	21st to end	Night	22% 11% 31% 29% 6%	1045

Page generated at 2024-01-11 03:22:39. Version ac07

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