Indian Foothills Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Indian Foothills Park clear sky chart from 2005-11-06 to 2025-05-26.

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% 8% 3 6% 4 4 4 3 5% 7% 44%	114192
	Night	12% 8% 3 7% 4 4 4 3 5% 6% 45%	115264
Transparency	Day	38% 6% 12% 25% 16% 3	117839
	Night	38% 5% 11% 24% 18% 3	119760
Seeing	Day	14% 10% 27% 27% 17% 5%	16370
	Night	15% 9% 31% 32% 13% 1	26312

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	14% 12% 4 10% 5% 5% 4 4 5% 5% 33%	3911
	11th to 20th	Day	8% 9% 4 9% 6% 7% 6% 3 4 5% 39%	4080
	21st to end	Day	15% 14% 4 9% 5% 3 4 3 3 4 36%	4488
February	1st to 10th	Day	17% 10% 4 8% 6% 4 4 3 5% 6% 34%	1800
	11th to 20th	Day	14% 10% 3 8% 5% 3 3 3 4 6% 40%	1754
	21st to end	Day	12% 10% 4 6% 4 3 4 4 5% 5% 41%	1675
March	1st to 10th	Day	15% 10% 4 4 3 2 2 2 3 4 51%	4936
	11th to 20th	Day	10% 6% 2 5% 3 3 3 3 5% 6% 52%	4980
	21st to end	Day	14% 12% 3 7% 5% 5% 5% 4 5% 8% 32%	5462
April	1st to 10th	Day	15% 7% 3 7% 4 4 3 3 5% 6% 42%	2390
	11th to 20th	Day	15% 10% 3 6% 5% 3 3 3 5% 6% 40%	2374
	21st to end	Day	21% 7% 3 7% 5% 4 5% 3 6% 6% 33%	2420
May	1st to 10th	Day	13% 7% 3 7% 5% 4 5% 5% 7% 9% 35%	4212
	11th to 20th	Day	16% 8% 3 7% 5% 4 4 3 6% 6% 39%	4277
	21st to end	Day	12% 6% 2 6% 4 4 5% 3 5% 7% 45%	4895
June	1st to 10th	Day	7% 5% 2 5% 4 4 4 5% 7% 10% 47%	2660
	11th to 20th	Day	8% 4 2 7% 4 4 5% 4 6% 9% 47%	2660
	21st to end	Day	7% 4 2 6% 4 4 5% 4 7% 8% 48%	2660
July	1st to 10th	Day	12% 6% 2 6% 4 4 5% 4 6% 8% 42%	4440
	11th to 20th	Day	5% 5% 2 5% 4 4 5% 4 6% 9% 53%	4136
	21st to end	Day	7% 5% 2 6% 4 5% 5% 4 7% 10% 45%	4465
August	1st to 10th	Day	5% 3 2 4 4 4 5% 4 7% 11% 52%	4104
	11th to 20th	Day	11% 5% 2 6% 4 3 5% 4 6% 8% 46%	3991
	21st to end	Day	6% 4 2 4 4 4 4 4 5% 9% 53%	4180
September	1st to 10th	Day	11% 4 2 5% 4 3 3 3 5% 7% 54%	2280
	11th to 20th	Day	10% 5% 1 5% 3 4 3 3 5% 8% 52%	2237
	21st to end	Day	8% 6% 2 5% 4 3 4 3 4 6% 54%	2005
October	1st to 10th	Day	12% 4 2 5% 4 3 4 3 4 5% 54%	1900
	11th to 20th	Day	14% 7% 2 5% 3 2 3 3 4 4 54%	1900
	21st to end	Day	16% 8% 3 6% 3 3 3 3 4 5% 47%	2090
November	1st to 10th	Day	12% 6% 1 5% 3 3 3 3 4 6% 52%	1928
	11th to 20th	Day	15% 7% 2 6% 4 3 3 2 6% 5% 49%	1702
	21st to end	Day	16% 10% 3 7% 3 3 3 2 4 5% 43%	1600
December	1st to 10th	Day	6% 8% 3 7% 3 4 3 3 4 7% 52%	2610
	11th to 20th	Day	11% 8% 4 8% 4 4 4 3 4 5% 46%	3008
	21st to end	Day	18% 21% 7% 11% 5% 4 3 2 4 4 22%	3982
January	1st to 10th	Night	13% 10% 5% 15% 5% 4 3 2 4 4 34%	6052
	11th to 20th	Night	11% 9% 4 10% 5% 6% 4 4 5% 4 38%	5900
	21st to end	Night	15% 11% 4 9% 4 4 4 3 4 4 38%	6490
February	1st to 10th	Night	14% 11% 4 8% 5% 5% 4 3 5% 5% 36%	2600
	11th to 20th	Night	14% 10% 3 6% 5% 3 4 3 4 6% 41%	2533
	21st to end	Night	13% 8% 3 7% 4 3 4 3 5% 6% 44%	1969
March	1st to 10th	Night	17% 10% 3 6% 3 2 3 2 4 4 46%	4919
	11th to 20th	Night	10% 6% 2 5% 3 3 3 3 4 6% 54%	4980
	21st to end	Night	14% 10% 4 7% 5% 5% 5% 4 5% 7% 34%	5467
April	1st to 10th	Night	11% 7% 3 5% 4 3 3 3 5% 7% 48%	2010
	11th to 20th	Night	14% 6% 2 7% 4 4 3 2 5% 6% 46%	1975
	21st to end	Night	16% 7% 3 8% 4 3 4 3 5% 7% 40%	1975
May	1st to 10th	Night	14% 8% 2 7% 4 5% 5% 4 6% 8% 37%	2913
	11th to 20th	Night	12% 8% 3 6% 5% 3 4 3 6% 9% 41%	2830
	21st to end	Night	11% 5% 2 5% 4 3 4 3 5% 8% 50%	2788
June	1st to 10th	Night	7% 3 1 4 4 3 5% 4 6% 9% 53%	1520
	11th to 20th	Night	5% 3 2 5% 5% 4 5% 3 7% 10% 51%	1520
	21st to end	Night	4 4 1 4 4 4 4 3 7% 8% 57%	1520
July	1st to 10th	Night	13% 6% 3 5% 3 3 4 3 6% 8% 45%	2530
	11th to 20th	Night	3 2 2 4 4 4 4 4 6% 9% 58%	2815
	21st to end	Night	5% 3 2 5% 5% 4 5% 5% 8% 9% 48%	3098
August	1st to 10th	Night	3 2 1 3 3 3 4 3 6% 11% 61%	2836
	11th to 20th	Night	11% 7% 2 5% 3 3 4 3 5% 7% 51%	2846
	21st to end	Night	4 3 1 5% 3 4 5% 4 6% 8% 57%	3476
September	1st to 10th	Night	10% 4 2 4 3 3 3 4 4 6% 58%	1900
	11th to 20th	Night	9% 4 1 5% 3 4 4 3 6% 6% 54%	1940
	21st to end	Night	8% 4 2 5% 3 4 4 3 4 6% 56%	2156
October	1st to 10th	Night	10% 4 1 4 3 3 3 3 5% 6% 58%	2280
	11th to 20th	Night	14% 5% 2 5% 3 3 3 2 4 5% 55%	2280
	21st to end	Night	16% 7% 2 4 3 3 4 3 4 4 50%	2508
November	1st to 10th	Night	11% 5% 1 4 3 2 3 2 4 7% 57%	2368
	11th to 20th	Night	11% 7% 3 5% 3 3 4 3 4 6% 52%	2695
	21st to end	Night	17% 8% 2 5% 3 4 3 3 3 4 47%	2800
December	1st to 10th	Night	8% 7% 3 6% 4 3 4 3 4 7% 52%	4580
	11th to 20th	Night	14% 9% 3 6% 4 3 4 3 5% 6% 43%	5199
	21st to end	Night	21% 17% 5% 9% 4 4 3 3 3 5% 26%	6996

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	52% 4 11% 21% 9% 2	3912
	11th to 20th	Day	48% 4 10% 21% 13% 4	4080
	21st to end	Day	52% 4 11% 14% 16% 3	4488
February	1st to 10th	Day	51% 5% 12% 21% 11% 1	1800
	11th to 20th	Day	48% 4 11% 20% 14% 3	1763
	21st to end	Day	44% 5% 10% 23% 16% 3	1675
March	1st to 10th	Day	39% 3 7% 25% 23% 3	4936
	11th to 20th	Day	32% 5% 9% 23% 25% 6%	4980
	21st to end	Day	49% 7% 16% 23% 5%	5464
April	1st to 10th	Day	42% 5% 11% 26% 15% 1	2390
	11th to 20th	Day	44% 5% 12% 23% 13% 2	2374
	21st to end	Day	50% 6% 11% 21% 11% 1	2420
May	1st to 10th	Day	42% 10% 13% 23% 12% 1	4250
	11th to 20th	Day	44% 8% 12% 24% 11%	4281
	21st to end	Day	37% 8% 10% 29% 15% 1	4908
June	1st to 10th	Day	30% 8% 16% 30% 14% 1	2660
	11th to 20th	Day	32% 8% 15% 27% 16% 2	2660
	21st to end	Day	29% 7% 17% 28% 14% 4	2660
July	1st to 10th	Day	38% 7% 12% 24% 16% 3	4371
	11th to 20th	Day	27% 7% 13% 33% 17% 2	4066
	21st to end	Day	31% 8% 19% 30% 11% 1	4325
August	1st to 10th	Day	24% 8% 17% 32% 17% 1	4090
	11th to 20th	Day	36% 6% 14% 28% 15% 1	4030
	21st to end	Day	26% 7% 15% 34% 14% 4	4179
September	1st to 10th	Day	30% 5% 13% 26% 20% 6%	2280
	11th to 20th	Day	30% 5% 11% 26% 24% 3	2237
	21st to end	Day	31% 5% 10% 28% 23% 3	2005
October	1st to 10th	Day	20% 2 6% 20% 40% 12%	3160
	11th to 20th	Day	22% 2 5% 22% 40% 9%	3140
	21st to end	Day	36% 3 8% 24% 26% 2	3428
November	1st to 10th	Day	34% 4 13% 24% 20% 4	1928
	11th to 20th	Day	37% 4 10% 25% 21% 3	1702
	21st to end	Day	44% 3 10% 28% 15%	1600
December	1st to 10th	Day	32% 4 15% 31% 16% 1	2610
	11th to 20th	Day	42% 4 15% 28% 11% 1	3005
	21st to end	Day	67% 4 12% 11% 6% 1	3982
January	1st to 10th	Night	55% 4 10% 22% 10% 1	6052
	11th to 20th	Night	48% 5% 10% 21% 13% 3	5900
	21st to end	Night	50% 4 10% 17% 16% 3	6490
February	1st to 10th	Night	48% 5% 11% 20% 13% 3	2600
	11th to 20th	Night	45% 4 11% 20% 17% 2	2534
	21st to end	Night	40% 5% 10% 22% 19% 4	1969
March	1st to 10th	Night	43% 4 7% 21% 22% 4	4919
	11th to 20th	Night	31% 4 7% 25% 27% 6%	4980
	21st to end	Night	47% 6% 13% 24% 8% 2	5467
April	1st to 10th	Night	35% 6% 10% 26% 19% 4	2010
	11th to 20th	Night	38% 5% 9% 27% 17% 5%	1975
	21st to end	Night	44% 6% 10% 23% 16% 1	1975
May	1st to 10th	Night	41% 10% 13% 19% 15% 1	2940
	11th to 20th	Night	40% 8% 13% 28% 11% 1	2831
	21st to end	Night	31% 8% 11% 23% 24% 2	2796
June	1st to 10th	Night	25% 8% 16% 31% 18% 4	1520
	11th to 20th	Night	26% 8% 13% 28% 21% 4	1520
	21st to end	Night	23% 6% 16% 30% 20% 6%	1520
July	1st to 10th	Night	36% 6% 11% 26% 18% 3	2490
	11th to 20th	Night	21% 6% 15% 36% 20% 2	2763
	21st to end	Night	27% 7% 21% 32% 12% 1	2999
August	1st to 10th	Night	18% 6% 22% 29% 24% 2	2826
	11th to 20th	Night	33% 5% 11% 28% 21% 1	2873
	21st to end	Night	24% 6% 16% 34% 16% 4	3476
September	1st to 10th	Night	28% 4 12% 23% 26% 7%	1900
	11th to 20th	Night	29% 5% 10% 26% 24% 5%	1940
	21st to end	Night	29% 5% 9% 27% 27% 4	2156
October	1st to 10th	Night	16% 3 6% 21% 45% 9%	3800
	11th to 20th	Night	23% 3 5% 23% 31% 15%	3779
	21st to end	Night	34% 4 7% 28% 25% 2	4120
November	1st to 10th	Night	29% 5% 12% 27% 22% 5%	2368
	11th to 20th	Night	35% 4 8% 25% 24% 4	2695
	21st to end	Night	42% 4 9% 26% 17% 2	2800
December	1st to 10th	Night	33% 4 12% 35% 14% 1	4580
	11th to 20th	Night	42% 4 13% 26% 15% 1	5201
	21st to end	Night	63% 4 12% 14% 6% 1	6996

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	20% 14% 39% 21% 6%	300
	11th to 20th	Day	29% 17% 37% 16% 2	300
	21st to end	Day	16% 16% 43% 21% 4	330
February	1st to 10th	Day	23% 15% 43% 16% 2	300
	11th to 20th	Day	21% 21% 37% 14% 6%	300
	21st to end	Day	17% 22% 40% 17% 3	249
March	1st to 10th	Day	17% 15% 49% 17% 2	300
	11th to 20th	Day	26% 14% 32% 24% 5%	300
	21st to end	Day	31% 21% 31% 14% 3	330
April	1st to 10th	Day	20% 18% 32% 23% 7% 1	490
	11th to 20th	Day	20% 17% 34% 22% 6% 1	492
	21st to end	Day	22% 12% 33% 23% 8% 1	520
May	1st to 10th	Day	17% 13% 33% 27% 9% 1	703
	11th to 20th	Day	18% 10% 26% 27% 14% 3	725
	21st to end	Day	15% 9% 28% 27% 16% 5%	760
June	1st to 10th	Day	7% 3 20% 34% 26% 9%	680
	11th to 20th	Day	10% 2 23% 36% 24% 5%	680
	21st to end	Day	6% 5% 31% 36% 18% 4	680
July	1st to 10th	Day	10% 4 15% 25% 33% 13%	671
	11th to 20th	Day	6% 2 19% 33% 31% 9%	668
	21st to end	Day	8% 3 15% 32% 32% 10%	739
August	1st to 10th	Day	7% 1 16% 39% 30% 7%	676
	11th to 20th	Day	9% 3 18% 37% 26% 8%	641
	21st to end	Day	9% 2 12% 28% 37% 12%	539
September	1st to 10th	Day	11% 3 15% 34% 27% 10%	490
	11th to 20th	Day	8% 2 16% 34% 30% 10%	447
	21st to end	Day	9% 7% 25% 31% 20% 8%	300
October	1st to 10th	Day	15% 7% 27% 27% 17% 8%	300
	11th to 20th	Day	12% 17% 38% 22% 11% 1	300
	21st to end	Day	25% 16% 33% 19% 6%	330
November	1st to 10th	Day	16% 10% 37% 24% 10% 3	300
	11th to 20th	Day	17% 16% 33% 22% 10% 2	300
	21st to end	Day	23% 16% 29% 25% 6%	300
December	1st to 10th	Day	11% 18% 37% 25% 8% 2	300
	11th to 20th	Day	16% 18% 37% 23% 6%	300
	21st to end	Day	22% 22% 37% 17% 2	330
January	1st to 10th	Night	16% 13% 40% 25% 7%	1000
	11th to 20th	Night	17% 15% 40% 23% 5% 1	1000
	21st to end	Night	16% 13% 40% 28% 3	1100
February	1st to 10th	Night	18% 13% 40% 26% 3	1000
	11th to 20th	Night	18% 14% 38% 27% 3	979
	21st to end	Night	18% 14% 43% 21% 3	649
March	1st to 10th	Night	18% 14% 39% 27% 3	600
	11th to 20th	Night	20% 10% 36% 29% 5% 1	600
	21st to end	Night	26% 12% 37% 22% 4	660
April	1st to 10th	Night	15% 12% 37% 31% 5%	600
	11th to 20th	Night	17% 13% 33% 30% 8%	593
	21st to end	Night	19% 9% 37% 28% 7%	600
May	1st to 10th	Night	15% 7% 33% 35% 9% 1	600
	11th to 20th	Night	16% 5% 27% 36% 15% 1	591
	21st to end	Night	13% 5% 28% 32% 20% 2	634
June	1st to 10th	Night	7% 3 19% 46% 22% 3	570
	11th to 20th	Night	5% 2 24% 46% 22% 2	570
	21st to end	Night	3 3 27% 45% 21% 1	570
July	1st to 10th	Night	10% 3 10% 41% 32% 4	555
	11th to 20th	Night	5% 1 14% 43% 34% 2	552
	21st to end	Night	7% 2 12% 43% 35% 2	624
August	1st to 10th	Night	4 3 14% 46% 32% 2	567
	11th to 20th	Night	7% 3 13% 41% 33% 3	564
	21st to end	Night	6% 1 11% 40% 40% 3	627
September	1st to 10th	Night	11% 2 15% 39% 28% 4	570
	11th to 20th	Night	12% 2 17% 37% 28% 5%	570
	21st to end	Night	9% 5% 23% 38% 23% 3	636
October	1st to 10th	Night	11% 5% 27% 33% 21% 3	760
	11th to 20th	Night	16% 9% 34% 33% 8%	760
	21st to end	Night	20% 12% 32% 28% 8%	836
November	1st to 10th	Night	14% 8% 33% 35% 10%	780
	11th to 20th	Night	14% 13% 37% 28% 8%	895
	21st to end	Night	20% 10% 37% 28% 5%	1000
December	1st to 10th	Night	17% 11% 39% 27% 6% 1	1000
	11th to 20th	Night	20% 10% 34% 30% 5%	1000
	21st to end	Night	21% 14% 37% 25% 3	1100

Page generated at 2025-05-23 08:20:57. Version ac07

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