Delhi (ON)
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Delhi (ON) clear sky chart from 2005-11-06 to 2026-05-17.

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	15% 10% 4 9% 5% 5% 5% 4 6% 7% 31%	132379
	Night	14% 10% 4 9% 5% 5% 4 4 5% 6% 33%	130377
Transparency	Day	49% 7% 13% 19% 11% 1	135977
	Night	49% 7% 13% 19% 12% 1	134866
Seeing	Day	18% 12% 28% 24% 13% 5%	16622
	Night	19% 11% 29% 28% 12% 1	26007

By Month

Percentage Cloud Cover NE (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	15% 15% 7% 15% 5% 5% 4 3 4 6% 20%	4883
	11th to 20th	Day	9% 21% 10% 21% 9% 6% 4 2 4 3 9%	5246
	21st to end	Day	15% 15% 6% 17% 8% 6% 5% 3 4 4 17%	5780
February	1st to 10th	Day	15% 17% 5% 12% 7% 7% 5% 3 4 5% 20%	1890
	11th to 20th	Day	13% 15% 8% 15% 6% 5% 5% 4 4 5% 21%	1843
	21st to end	Day	17% 13% 6% 12% 6% 5% 5% 4 5% 6% 21%	1683
March	1st to 10th	Day	17% 12% 5% 12% 6% 4 4 3 4 5% 27%	4997
	11th to 20th	Day	11% 13% 4 10% 6% 4 4 3 5% 8% 31%	5090
	21st to end	Day	19% 11% 4 10% 5% 5% 4 3 4 5% 30%	5586
April	1st to 10th	Day	17% 14% 4 8% 5% 4 4 3 5% 6% 29%	2421
	11th to 20th	Day	16% 11% 4 9% 6% 4 4 3 5% 7% 33%	2625
	21st to end	Day	19% 9% 3 7% 4 4 4 4 4 6% 33%	2730
May	1st to 10th	Day	20% 9% 3 8% 5% 5% 5% 3 5% 7% 30%	6018
	11th to 20th	Day	16% 10% 4 8% 5% 5% 4 4 6% 7% 32%	6071
	21st to end	Day	16% 7% 3 7% 4 4 4 4 5% 7% 38%	6949
June	1st to 10th	Day	13% 6% 3 6% 5% 4 5% 4 6% 8% 40%	2800
	11th to 20th	Day	11% 6% 3 7% 5% 5% 5% 5% 8% 8% 37%	2800
	21st to end	Day	12% 6% 2 5% 4 4 5% 5% 6% 10% 40%	2991
July	1st to 10th	Day	9% 5% 2 7% 5% 5% 5% 5% 7% 10% 42%	6525
	11th to 20th	Day	9% 5% 2 6% 5% 5% 5% 4 7% 9% 43%	6050
	21st to end	Day	7% 5% 2 6% 5% 5% 5% 4 6% 9% 46%	6424
August	1st to 10th	Day	16% 6% 2 5% 4 4 5% 4 7% 9% 38%	4234
	11th to 20th	Day	11% 6% 3 6% 5% 5% 6% 5% 8% 10% 35%	4174
	21st to end	Day	9% 6% 3 7% 5% 4 5% 4 6% 9% 42%	4552
September	1st to 10th	Day	11% 6% 2 6% 5% 5% 5% 5% 6% 8% 41%	2398
	11th to 20th	Day	9% 5% 2 5% 4 4 5% 3 6% 8% 48%	2200
	21st to end	Day	15% 7% 3 8% 4 6% 5% 4 7% 7% 36%	2200
October	1st to 10th	Day	16% 7% 3 7% 5% 5% 4 4 6% 6% 38%	2009
	11th to 20th	Day	17% 10% 3 7% 4 4 5% 4 5% 6% 33%	2000
	21st to end	Day	22% 10% 4 9% 5% 5% 5% 4 6% 7% 25%	2200
November	1st to 10th	Day	15% 8% 3 8% 6% 4 5% 4 6% 7% 35%	1856
	11th to 20th	Day	15% 13% 4 9% 5% 4 5% 4 6% 8% 29%	1680
	21st to end	Day	19% 15% 4 9% 5% 5% 5% 5% 6% 6% 21%	1680
December	1st to 10th	Day	18% 18% 6% 10% 6% 5% 5% 4 6% 6% 15%	2680
	11th to 20th	Day	21% 18% 5% 9% 5% 4 5% 4 5% 5% 20%	3066
	21st to end	Day	26% 19% 5% 11% 5% 5% 4 3 5% 5% 12%	4048
January	1st to 10th	Night	14% 15% 5% 13% 7% 6% 5% 4 5% 6% 20%	7994
	11th to 20th	Night	11% 17% 7% 16% 8% 6% 5% 4 5% 5% 17%	7639
	21st to end	Night	16% 14% 6% 15% 7% 5% 5% 3 4 4 20%	8401
February	1st to 10th	Night	15% 16% 4 11% 7% 5% 5% 4 5% 5% 24%	2730
	11th to 20th	Night	15% 12% 6% 10% 7% 5% 5% 4 6% 6% 25%	2663
	21st to end	Night	17% 12% 5% 11% 7% 5% 5% 4 5% 6% 23%	2120
March	1st to 10th	Night	15% 9% 4 8% 6% 4 4 4 5% 6% 33%	5063
	11th to 20th	Night	11% 9% 4 8% 4 4 4 4 6% 8% 39%	5089
	21st to end	Night	17% 10% 4 7% 4 4 4 3 4 5% 37%	5588
April	1st to 10th	Night	18% 10% 4 7% 5% 5% 5% 4 5% 7% 31%	2197
	11th to 20th	Night	18% 8% 3 7% 4 4 6% 4 5% 5% 36%	1962
	21st to end	Night	14% 7% 2 8% 6% 5% 4 4 6% 7% 36%	1890
May	1st to 10th	Night	21% 9% 3 7% 5% 4 4 3 5% 6% 34%	4143
	11th to 20th	Night	13% 9% 3 8% 6% 4 5% 4 5% 6% 37%	3951
	21st to end	Night	18% 5% 2 5% 3 4 4 4 5% 8% 43%	3926
June	1st to 10th	Night	11% 6% 2 6% 5% 4 4 5% 6% 8% 43%	1600
	11th to 20th	Night	9% 5% 3 6% 5% 5% 5% 5% 8% 10% 42%	1594
	21st to end	Night	10% 6% 2 5% 4 4 4 4 6% 8% 46%	1400
July	1st to 10th	Night	7% 5% 2 6% 4 4 4 3 6% 9% 49%	3419
	11th to 20th	Night	8% 5% 2 6% 4 4 4 4 6% 8% 49%	3892
	21st to end	Night	7% 5% 2 6% 4 4 4 4 6% 7% 50%	4428
August	1st to 10th	Night	10% 5% 3 6% 5% 4 5% 4 5% 9% 45%	2915
	11th to 20th	Night	11% 6% 2 6% 3 3 4 4 6% 8% 48%	2875
	21st to end	Night	7% 5% 2 6% 3 4 5% 4 6% 9% 49%	3312
September	1st to 10th	Night	11% 6% 3 7% 4 3 4 3 5% 6% 46%	2000
	11th to 20th	Night	8% 4 2 5% 4 3 3 3 5% 6% 56%	2199
	21st to end	Night	16% 7% 2 7% 5% 4 4 4 6% 5% 40%	2200
October	1st to 10th	Night	14% 6% 2 7% 4 3 4 3 5% 7% 46%	2390
	11th to 20th	Night	17% 9% 3 7% 5% 5% 3 3 4 6% 37%	2400
	21st to end	Night	20% 9% 3 7% 5% 4 4 4 5% 7% 33%	2640
November	1st to 10th	Night	15% 8% 2 7% 4 4 4 4 6% 7% 40%	2659
	11th to 20th	Night	16% 10% 3 8% 6% 6% 4 4 6% 8% 30%	2940
	21st to end	Night	20% 13% 4 8% 5% 4 5% 4 5% 7% 25%	2940
December	1st to 10th	Night	14% 16% 5% 10% 6% 6% 6% 5% 7% 7% 19%	4720
	11th to 20th	Night	17% 18% 5% 10% 6% 4 4 3 4 5% 23%	5348
	21st to end	Night	25% 18% 5% 9% 5% 4 4 3 4 5% 18%	7150

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	65% 6% 12% 11% 7%	4884
	11th to 20th	Day	78% 6% 8% 4 4	5280
	21st to end	Day	70% 6% 10% 8% 6%	5780
February	1st to 10th	Day	66% 6% 10% 12% 5%	1890
	11th to 20th	Day	64% 6% 9% 15% 5%	1852
	21st to end	Day	62% 7% 12% 13% 5% 1	1683
March	1st to 10th	Day	58% 6% 14% 16% 6%	5000
	11th to 20th	Day	49% 7% 18% 18% 6% 2	5090
	21st to end	Day	54% 6% 11% 19% 9% 1	5586
April	1st to 10th	Day	55% 6% 10% 17% 11% 1	2421
	11th to 20th	Day	50% 6% 11% 20% 11% 1	2625
	21st to end	Day	49% 8% 11% 19% 11% 2	2730
May	1st to 10th	Day	51% 7% 12% 16% 9% 5%	6027
	11th to 20th	Day	48% 8% 13% 19% 10% 1	6075
	21st to end	Day	43% 7% 12% 19% 16% 3	6949
June	1st to 10th	Day	39% 8% 14% 24% 14% 2	2800
	11th to 20th	Day	39% 9% 16% 21% 14% 2	2800
	21st to end	Day	37% 8% 15% 24% 15%	2991
July	1st to 10th	Day	36% 7% 13% 25% 16% 2	6456
	11th to 20th	Day	35% 7% 15% 27% 15% 1	5977
	21st to end	Day	33% 7% 14% 24% 20% 1	6240
August	1st to 10th	Day	41% 8% 16% 21% 14% 1	4221
	11th to 20th	Day	40% 9% 17% 25% 9% 1	4213
	21st to end	Day	36% 7% 14% 30% 11% 1	4552
September	1st to 10th	Day	37% 9% 16% 25% 12% 1	2398
	11th to 20th	Day	31% 8% 16% 30% 15%	2200
	21st to end	Day	45% 7% 14% 22% 11% 1	2200
October	1st to 10th	Day	37% 6% 16% 23% 17% 1	3269
	11th to 20th	Day	38% 6% 15% 22% 18%	3240
	21st to end	Day	48% 6% 16% 22% 8%	3538
November	1st to 10th	Day	47% 7% 13% 23% 8% 2	1856
	11th to 20th	Day	51% 9% 15% 15% 9%	1680
	21st to end	Day	60% 9% 15% 13% 4	1680
December	1st to 10th	Day	67% 7% 15% 9% 2	2680
	11th to 20th	Day	63% 8% 13% 7% 8%	3066
	21st to end	Day	74% 6% 8% 7% 4	4048
January	1st to 10th	Night	61% 7% 12% 15% 5%	7994
	11th to 20th	Night	66% 7% 12% 9% 6% 1	7680
	21st to end	Night	66% 5% 8% 11% 9%	8401
February	1st to 10th	Night	61% 7% 11% 14% 5% 1	2730
	11th to 20th	Night	58% 6% 13% 16% 6%	2665
	21st to end	Night	58% 8% 12% 15% 7%	2120
March	1st to 10th	Night	50% 5% 15% 18% 10% 2	5073
	11th to 20th	Night	41% 7% 18% 21% 12% 1	5090
	21st to end	Night	48% 6% 11% 18% 16% 2	5588
April	1st to 10th	Night	53% 6% 12% 16% 12% 2	2197
	11th to 20th	Night	47% 7% 9% 20% 15% 2	1962
	21st to end	Night	43% 8% 11% 20% 14% 3	1890
May	1st to 10th	Night	50% 6% 11% 14% 12% 8%	4150
	11th to 20th	Night	46% 8% 13% 21% 10% 2	3952
	21st to end	Night	39% 7% 13% 22% 18% 2	3927
June	1st to 10th	Night	37% 7% 12% 25% 15% 4	1600
	11th to 20th	Night	35% 8% 14% 24% 16% 2	1594
	21st to end	Night	34% 8% 14% 22% 20% 1	1400
July	1st to 10th	Night	31% 5% 14% 26% 19% 4	3379
	11th to 20th	Night	33% 6% 13% 29% 18% 2	3842
	21st to end	Night	31% 7% 13% 21% 25% 3	4297
August	1st to 10th	Night	36% 6% 15% 24% 17% 2	2904
	11th to 20th	Night	33% 8% 18% 29% 11% 1	2902
	21st to end	Night	30% 7% 14% 32% 16% 1	3312
September	1st to 10th	Night	36% 7% 12% 27% 15% 2	2000
	11th to 20th	Night	27% 6% 15% 33% 19% 1	2199
	21st to end	Night	44% 7% 11% 24% 13% 1	2200
October	1st to 10th	Night	31% 5% 9% 29% 25% 2	3910
	11th to 20th	Night	41% 5% 14% 23% 16%	3899
	21st to end	Night	39% 6% 15% 25% 15% 1	4252
November	1st to 10th	Night	41% 7% 13% 24% 13% 1	2659
	11th to 20th	Night	50% 8% 14% 18% 9% 1	2940
	21st to end	Night	57% 8% 16% 14% 4 1	2940
December	1st to 10th	Night	61% 8% 16% 11% 3	4720
	11th to 20th	Night	62% 6% 11% 12% 9% 1	5348
	21st to end	Night	67% 7% 11% 10% 5%	7150

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	23% 22% 35% 13% 7% 2	261
	11th to 20th	Day	25% 21% 38% 11% 4 1	330
	21st to end	Day	25% 20% 33% 18% 4 1	363
February	1st to 10th	Day	22% 19% 38% 15% 5% 1	330
	11th to 20th	Day	24% 21% 36% 17% 2	330
	21st to end	Day	24% 28% 35% 11% 1	273
March	1st to 10th	Day	23% 15% 35% 20% 6% 1	519
	11th to 20th	Day	23% 18% 35% 18% 5% 1	540
	21st to end	Day	28% 15% 30% 21% 5%	594
April	1st to 10th	Day	21% 18% 31% 21% 7% 1	540
	11th to 20th	Day	23% 16% 29% 19% 10% 3	532
	21st to end	Day	22% 13% 33% 21% 8% 2	540
May	1st to 10th	Day	24% 11% 30% 23% 8% 4	543
	11th to 20th	Day	17% 9% 28% 25% 16% 4	551
	21st to end	Day	14% 9% 24% 29% 17% 7%	573
June	1st to 10th	Day	12% 9% 33% 31% 12% 3	530
	11th to 20th	Day	15% 8% 25% 32% 15% 5%	530
	21st to end	Day	12% 6% 32% 33% 14% 3	721
July	1st to 10th	Day	10% 4 22% 30% 25% 9%	600
	11th to 20th	Day	12% 6% 23% 29% 19% 10%	524
	21st to end	Day	8% 3 25% 34% 23% 7%	576
August	1st to 10th	Day	10% 3 20% 32% 22% 14%	526
	11th to 20th	Day	10% 6% 19% 29% 21% 15%	519
	21st to end	Day	11% 4 22% 29% 23% 11%	583
September	1st to 10th	Day	12% 6% 23% 25% 20% 13%	530
	11th to 20th	Day	8% 4 16% 27% 29% 17%	530
	21st to end	Day	18% 9% 23% 28% 16% 7%	530
October	1st to 10th	Day	17% 10% 25% 24% 18% 6%	530
	11th to 20th	Day	17% 16% 34% 23% 7% 3	530
	21st to end	Day	25% 14% 31% 21% 8%	583
November	1st to 10th	Day	18% 23% 32% 18% 7% 2	339
	11th to 20th	Day	24% 19% 30% 19% 6% 3	220
	21st to end	Day	30% 15% 34% 17% 4	220
December	1st to 10th	Day	27% 24% 27% 16% 5% 1	220
	11th to 20th	Day	26% 25% 33% 13% 3	220
	21st to end	Day	29% 19% 33% 15% 4	242
January	1st to 10th	Night	22% 19% 35% 19% 5%	840
	11th to 20th	Night	25% 22% 31% 20% 3	840
	21st to end	Night	20% 15% 38% 23% 5%	924
February	1st to 10th	Night	24% 15% 36% 23% 2	840
	11th to 20th	Night	22% 15% 36% 23% 4	823
	21st to end	Night	22% 16% 37% 22% 2	692
March	1st to 10th	Night	17% 14% 35% 27% 6%	840
	11th to 20th	Night	21% 12% 37% 23% 7%	840
	21st to end	Night	22% 12% 32% 26% 9%	924
April	1st to 10th	Night	23% 13% 31% 28% 4	840
	11th to 20th	Night	22% 12% 32% 25% 8% 1	718
	21st to end	Night	17% 7% 34% 33% 9%	630
May	1st to 10th	Night	19% 7% 28% 31% 13% 1	630
	11th to 20th	Night	16% 5% 27% 37% 14% 1	552
	21st to end	Night	13% 5% 27% 35% 19% 1	433
June	1st to 10th	Night	13% 4 29% 40% 14% 1	400
	11th to 20th	Night	11% 3 29% 42% 16%	400
	21st to end	Night	12% 5% 26% 43% 15% 1	400
July	1st to 10th	Night	6% 3 20% 46% 22% 3	390
	11th to 20th	Night	9% 4 20% 40% 24% 3	509
	21st to end	Night	9% 2 18% 47% 23% 2	657
August	1st to 10th	Night	7% 2 15% 43% 30% 3	597
	11th to 20th	Night	10% 3 17% 35% 33% 3	594
	21st to end	Night	9% 2 21% 38% 26% 3	710
September	1st to 10th	Night	13% 5% 19% 34% 24% 5%	800
	11th to 20th	Night	11% 4 14% 35% 31% 5%	800
	21st to end	Night	17% 7% 21% 31% 20% 5%	800
October	1st to 10th	Night	16% 8% 24% 30% 20% 3	800
	11th to 20th	Night	20% 12% 30% 27% 10% 2	800
	21st to end	Night	24% 10% 33% 27% 6%	880
November	1st to 10th	Night	19% 11% 31% 27% 10% 1	820
	11th to 20th	Night	21% 18% 33% 21% 7% 1	840
	21st to end	Night	27% 14% 33% 20% 6%	840
December	1st to 10th	Night	28% 17% 33% 17% 5% 1	840
	11th to 20th	Night	23% 19% 37% 18% 3	840
	21st to end	Night	30% 13% 32% 22% 2	924

Page generated at 2026-05-14 01:58:59. Version ac07

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