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 2024-11-12.

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	12% 6% 2 6% 4 4 4 4 5% 7% 44%	100680
	Night	13% 6% 2 5% 4 3 4 3 5% 7% 49%	98540
Transparency	Day	21% 47% 6% 13% 11% 3	104326
	Night	19% 46% 5% 13% 13% 5%	103035
Seeing	Day	13% 8% 20% 25% 23% 11%	15285
	Night	14% 6% 23% 32% 21% 3	25040

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	17% 13% 3 7% 3 2 2 2 3 3 45%	2847
	11th to 20th	Day	21% 8% 3 6% 3 3 3 2 4 4 46%	2850
	21st to end	Day	23% 7% 3 5% 3 2 3 2 3 5% 44%	3135
February	1st to 10th	Day	20% 8% 3 5% 4 3 4 3 4 5% 42%	1783
	11th to 20th	Day	21% 10% 3 6% 3 3 3 2 3 5% 42%	1848
	21st to end	Day	22% 9% 3 7% 4 3 3 2 4 5% 38%	1570
March	1st to 10th	Day	20% 13% 3 9% 4 4 4 3 3 5% 33%	3339
	11th to 20th	Day	14% 7% 3 7% 5% 3 5% 4 5% 6% 42%	3480
	21st to end	Day	13% 8% 3 9% 5% 4 4 3 4 6% 42%	3936
April	1st to 10th	Day	13% 5% 3 7% 4 4 4 4 6% 7% 44%	2280
	11th to 20th	Day	15% 7% 2 6% 3 3 3 4 5% 7% 45%	2254
	21st to end	Day	11% 6% 3 7% 5% 5% 4 3 5% 6% 45%	2280
May	1st to 10th	Day	13% 7% 2 6% 5% 5% 4 4 5% 8% 42%	3765
	11th to 20th	Day	10% 5% 2 7% 5% 4 5% 4 7% 9% 41%	3764
	21st to end	Day	12% 6% 2 7% 6% 5% 5% 5% 7% 9% 36%	4682
June	1st to 10th	Day	8% 5% 2 6% 5% 6% 6% 4 6% 9% 43%	2660
	11th to 20th	Day	6% 3 2 5% 5% 5% 5% 4 6% 10% 49%	2660
	21st to end	Day	5% 4 2 5% 5% 4 5% 5% 7% 10% 50%	2660
July	1st to 10th	Day	6% 5% 2 7% 5% 6% 6% 6% 9% 11% 38%	4159
	11th to 20th	Day	8% 6% 2 6% 5% 5% 6% 4 8% 11% 38%	4120
	21st to end	Day	15% 8% 3 7% 5% 5% 6% 5% 7% 7% 32%	4465
August	1st to 10th	Day	3 2 1 4 3 3 4 3 6% 8% 64%	3894
	11th to 20th	Day	6% 3 2 6% 5% 5% 6% 5% 7% 10% 46%	3729
	21st to end	Day	7% 4 2 5% 5% 4 6% 4 6% 8% 50%	4180
September	1st to 10th	Day	8% 5% 2 6% 5% 6% 6% 4 5% 8% 46%	2280
	11th to 20th	Day	12% 5% 3 6% 4 4 4 5% 5% 7% 46%	2280
	21st to end	Day	10% 4 2 4 4 3 4 3 5% 7% 54%	2057
October	1st to 10th	Day	7% 3 1 4 3 3 3 4 5% 8% 58%	1900
	11th to 20th	Day	12% 4 2 5% 2 2 2 2 5% 6% 59%	1900
	21st to end	Day	17% 6% 2 4 2 3 3 3 4 4 53%	2090
November	1st to 10th	Day	14% 4 2 4 3 3 3 2 3 5% 57%	1958
	11th to 20th	Day	11% 6% 2 5% 4 4 3 3 3 6% 53%	1724
	21st to end	Day	19% 7% 2 6% 4 3 3 2 5% 6% 44%	1710
December	1st to 10th	Day	18% 9% 3 6% 4 4 4 3 4 5% 42%	1644
	11th to 20th	Day	15% 8% 3 6% 5% 4 4 3 4 6% 43%	1918
	21st to end	Day	13% 7% 3 7% 6% 5% 6% 4 5% 5% 38%	2879
January	1st to 10th	Night	17% 8% 2 7% 4 3 3 2 3 5% 45%	4108
	11th to 20th	Night	20% 6% 2 5% 3 3 3 2 4 4 50%	4120
	21st to end	Night	24% 8% 2 4 2 2 2 2 4 4 46%	4532
February	1st to 10th	Night	21% 7% 2 6% 3 4 3 2 3 4 43%	2394
	11th to 20th	Night	19% 8% 2 5% 3 3 4 3 4 4 44%	2218
	21st to end	Night	22% 7% 2 5% 4 3 4 2 4 5% 42%	1884
March	1st to 10th	Night	17% 9% 3 6% 4 4 3 3 5% 6% 40%	3541
	11th to 20th	Night	14% 6% 2 6% 4 3 4 3 5% 7% 46%	3480
	21st to end	Night	14% 7% 2 7% 5% 3 4 3 5% 6% 43%	3695
April	1st to 10th	Night	12% 4 3 6% 4 4 4 4 6% 7% 49%	1900
	11th to 20th	Night	14% 5% 2 5% 4 3 3 4 5% 7% 49%	1875
	21st to end	Night	11% 5% 3 5% 5% 3 3 3 5% 6% 50%	1900
May	1st to 10th	Night	17% 7% 2 6% 3 3 4 3 6% 8% 41%	3130
	11th to 20th	Night	15% 6% 2 5% 3 3 4 3 5% 7% 46%	3129
	21st to end	Night	10% 5% 3 7% 5% 4 6% 4 7% 9% 41%	2863
June	1st to 10th	Night	5% 4 2 5% 5% 4 5% 3 7% 11% 50%	1520
	11th to 20th	Night	4 4 2 4 3 3 4 4 7% 10% 56%	1520
	21st to end	Night	4 3 2 4 4 5% 4 4 6% 8% 57%	1520
July	1st to 10th	Night	5% 4 2 5% 4 4 5% 5% 9% 12% 46%	2805
	11th to 20th	Night	7% 4 2 4 4 4 5% 5% 8% 11% 47%	2850
	21st to end	Night	13% 8% 2 6% 4 5% 4 4 6% 8% 40%	3098
August	1st to 10th	Night	2 2 1 2 2 2 2 3 5% 7% 72%	3036
	11th to 20th	Night	4 4 1 4 3 4 4 4 6% 11% 54%	3100
	21st to end	Night	5% 4 2 5% 4 4 4 4 5% 8% 54%	3476
September	1st to 10th	Night	8% 5% 2 5% 5% 4 4 3 4 6% 53%	1900
	11th to 20th	Night	11% 5% 2 5% 4 3 5% 3 5% 6% 51%	1900
	21st to end	Night	9% 5% 2 4 3 2 3 3 4 7% 58%	2098
October	1st to 10th	Night	7% 2 1 4 2 3 2 3 4 6% 66%	2280
	11th to 20th	Night	10% 4 2 4 2 3 3 2 5% 5% 60%	2280
	21st to end	Night	15% 5% 1 5% 2 2 2 3 3 4 56%	2508
November	1st to 10th	Night	12% 5% 2 4 4 3 3 2 4 5% 56%	2340
	11th to 20th	Night	11% 4 2 4 4 3 3 2 4 6% 56%	2476
	21st to end	Night	14% 6% 3 5% 4 3 3 3 4 5% 51%	2470
December	1st to 10th	Night	17% 7% 2 5% 4 3 3 3 5% 5% 45%	2531
	11th to 20th	Night	16% 7% 2 5% 4 4 3 3 4 5% 49%	3279
	21st to end	Night	15% 7% 3 7% 5% 4 5% 3 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	32% 36% 2 12% 16% 2	2848
	11th to 20th	Day	28% 37% 7% 15% 11% 1	2850
	21st to end	Day	28% 40% 3 11% 14% 3	3135
February	1st to 10th	Day	18% 65% 2 8% 5% 2	1783
	11th to 20th	Day	19% 64% 2 9% 5% 2	1858
	21st to end	Day	20% 64% 3 5% 4 4	1570
March	1st to 10th	Day	39% 41% 3 5% 8% 5%	3339
	11th to 20th	Day	24% 40% 5% 16% 11% 4	3480
	21st to end	Day	27% 40% 3 13% 16% 1	3936
April	1st to 10th	Day	15% 66% 3 8% 6% 2	2280
	11th to 20th	Day	18% 66% 3 8% 5% 2	2254
	21st to end	Day	14% 65% 4 7% 9% 1	2280
May	1st to 10th	Day	22% 41% 7% 21% 8% 1	3800
	11th to 20th	Day	24% 42% 9% 16% 8% 1	3768
	21st to end	Day	29% 42% 7% 15% 6% 1	4695
June	1st to 10th	Day	13% 66% 4 8% 7% 1	2660
	11th to 20th	Day	12% 66% 6% 9% 5% 1	2660
	21st to end	Day	11% 65% 6% 13% 5%	2660
July	1st to 10th	Day	23% 40% 13% 18% 6%	4095
	11th to 20th	Day	23% 38% 10% 25% 5%	4051
	21st to end	Day	36% 36% 8% 15% 4	4325
August	1st to 10th	Day	7% 38% 10% 22% 21% 2	3880
	11th to 20th	Day	19% 39% 12% 23% 6%	3765
	21st to end	Day	20% 38% 6% 17% 18% 1	4179
September	1st to 10th	Day	12% 61% 6% 10% 8% 2	2280
	11th to 20th	Day	13% 61% 5% 10% 10% 1	2280
	21st to end	Day	14% 60% 6% 11% 7% 2	2057
October	1st to 10th	Day	7% 37% 3 6% 18% 30%	3160
	11th to 20th	Day	7% 36% 2 14% 26% 16%	3140
	21st to end	Day	16% 36% 2 13% 25% 8%	3428
November	1st to 10th	Day	21% 56% 3 6% 11% 3	1958
	11th to 20th	Day	15% 59% 2 8% 10% 5%	1724
	21st to end	Day	19% 59% 3 8% 10% 1	1710
December	1st to 10th	Day	20% 59% 2 9% 7% 3	1644
	11th to 20th	Day	20% 48% 2 11% 16% 3	1915
	21st to end	Day	31% 39% 4 13% 12% 2	2879
January	1st to 10th	Night	29% 37% 2 12% 17% 2	4108
	11th to 20th	Night	26% 36% 4 14% 15% 4	4120
	21st to end	Night	27% 38% 5% 13% 13% 3	4532
February	1st to 10th	Night	18% 65% 3 5% 8% 2	2394
	11th to 20th	Night	16% 64% 3 9% 6% 3	2219
	21st to end	Night	18% 65% 2 5% 6% 5%	1884
March	1st to 10th	Night	31% 42% 5% 6% 10% 6%	3541
	11th to 20th	Night	22% 40% 4 15% 11% 7%	3480
	21st to end	Night	24% 41% 5% 11% 18% 1	3695
April	1st to 10th	Night	13% 65% 4 8% 7% 3	1900
	11th to 20th	Night	15% 66% 3 8% 7% 2	1875
	21st to end	Night	12% 65% 4 8% 10% 2	1900
May	1st to 10th	Night	27% 40% 8% 14% 10% 1	3160
	11th to 20th	Night	23% 40% 7% 20% 8%	3130
	21st to end	Night	28% 42% 8% 14% 7% 1	2871
June	1st to 10th	Night	10% 65% 7% 10% 6% 2	1520
	11th to 20th	Night	8% 66% 7% 9% 8% 1	1520
	21st to end	Night	10% 65% 4 14% 7%	1520
July	1st to 10th	Night	19% 40% 16% 16% 9% 1	2760
	11th to 20th	Night	18% 38% 8% 28% 7% 1	2796
	21st to end	Night	33% 36% 6% 16% 9%	2999
August	1st to 10th	Night	5% 36% 6% 23% 27% 3	3026
	11th to 20th	Night	12% 39% 14% 23% 10%	3130
	21st to end	Night	18% 38% 4 15% 23% 3	3476
September	1st to 10th	Night	10% 60% 6% 14% 8% 2	1900
	11th to 20th	Night	11% 61% 4 10% 12% 2	1900
	21st to end	Night	10% 61% 5% 14% 9% 2	2098
October	1st to 10th	Night	5% 37% 4 10% 16% 28%	3800
	11th to 20th	Night	6% 36% 2 11% 23% 23%	3779
	21st to end	Night	13% 36% 3 13% 24% 12%	4120
November	1st to 10th	Night	20% 57% 3 7% 10% 4	2340
	11th to 20th	Night	14% 59% 3 10% 10% 4	2476
	21st to end	Night	13% 60% 3 10% 12% 2	2470
December	1st to 10th	Night	18% 59% 4 7% 8% 3	2531
	11th to 20th	Night	19% 49% 2 9% 18% 3	3281
	21st to end	Night	28% 39% 4 12% 14% 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	26% 14% 39% 16% 3 2	270
	21st to end	Day	19% 15% 42% 18% 5%	297
February	1st to 10th	Day	23% 14% 34% 22% 5% 2	270
	11th to 20th	Day	31% 17% 32% 15% 4	270
	21st to end	Day	33% 22% 29% 11% 4	225
March	1st to 10th	Day	20% 17% 36% 17% 9% 1	270
	11th to 20th	Day	17% 22% 33% 24% 4	270
	21st to end	Day	15% 18% 36% 20% 10%	368
April	1st to 10th	Day	17% 13% 36% 26% 8%	460
	11th to 20th	Day	20% 15% 27% 25% 11% 2	452
	21st to end	Day	14% 12% 31% 25% 16% 2	460
May	1st to 10th	Day	14% 12% 25% 31% 16% 2	463
	11th to 20th	Day	12% 5% 24% 25% 25% 7%	487
	21st to end	Day	10% 4 19% 32% 25% 10%	713
June	1st to 10th	Day	10% 3 13% 30% 29% 16%	680
	11th to 20th	Day	5% 3 11% 33% 36% 13%	680
	21st to end	Day	6% 2 10% 33% 31% 18%	680
July	1st to 10th	Day	7% 2 7% 24% 39% 21%	671
	11th to 20th	Day	6% 1 7% 27% 35% 24%	668
	21st to end	Day	7% 3 5% 23% 39% 24%	739
August	1st to 10th	Day	5% 2 8% 23% 42% 20%	557
	11th to 20th	Day	11% 1 7% 21% 41% 18%	479
	21st to end	Day	12% 1 6% 18% 36% 28%	539
September	1st to 10th	Day	7% 2 9% 25% 37% 19%	490
	11th to 20th	Day	12% 2 10% 23% 32% 21%	490
	21st to end	Day	14% 3 12% 24% 31% 15%	457
October	1st to 10th	Day	8% 2 21% 28% 30% 11%	300
	11th to 20th	Day	8% 6% 32% 34% 15% 5%	300
	21st to end	Day	19% 9% 25% 29% 14% 3	330
November	1st to 10th	Day	21% 5% 24% 29% 18% 2	300
	11th to 20th	Day	10% 13% 33% 32% 11% 1	273
	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% 11% 35% 26% 5% 1	950
	21st to end	Night	20% 9% 38% 29% 3	1045
February	1st to 10th	Night	25% 11% 34% 25% 5%	874
	11th to 20th	Night	22% 12% 34% 29% 3	743
	21st to end	Night	24% 15% 34% 24% 3	628
March	1st to 10th	Night	19% 10% 31% 33% 7%	646
	11th to 20th	Night	18% 10% 32% 31% 8% 1	570
	21st to end	Night	19% 8% 30% 32% 10%	627
April	1st to 10th	Night	14% 9% 35% 34% 8% 1	570
	11th to 20th	Night	15% 9% 30% 33% 12% 1	563
	21st to end	Night	14% 8% 31% 34% 13% 1	570
May	1st to 10th	Night	12% 6% 22% 44% 15% 1	570
	11th to 20th	Night	13% 4 24% 38% 20% 2	561
	21st to end	Night	6% 2 18% 39% 29% 6%	617
June	1st to 10th	Night	6% 2 11% 38% 36% 6%	570
	11th to 20th	Night	5% 1 9% 36% 43% 6%	570
	21st to end	Night	5% 1 6% 35% 44% 9%	570
July	1st to 10th	Night	4 1 4 33% 49% 9%	555
	11th to 20th	Night	5% 1 5% 25% 53% 10%	552
	21st to end	Night	6% 4 30% 49% 10%	624
August	1st to 10th	Night	4 1 4 26% 53% 11%	567
	11th to 20th	Night	6% 2 4 33% 46% 9%	564
	21st to end	Night	10% 1 5% 25% 48% 12%	627
September	1st to 10th	Night	9% 1 8% 34% 41% 7%	570
	11th to 20th	Night	11% 2 9% 29% 41% 7%	570
	21st to end	Night	11% 2 12% 33% 36% 5%	740
October	1st to 10th	Night	7% 2 14% 35% 35% 6%	760
	11th to 20th	Night	11% 5% 22% 43% 18% 1	760
	21st to end	Night	17% 6% 22% 35% 19% 1	836
November	1st to 10th	Night	14% 5% 24% 36% 20% 2	780
	11th to 20th	Night	13% 6% 32% 36% 13% 1	765
	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 2024-11-08 21:45:39. Version ac07

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