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 2025-01-22.

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 8% 5% 5% 5% 4 6% 7% 32%	105354
	Night	15% 10% 4 8% 5% 4 4 4 5% 7% 33%	103966
Transparency	Day	48% 8% 14% 19% 10% 1	108962
	Night	48% 7% 13% 19% 11% 1	108446
Seeing	Day	18% 12% 28% 24% 13% 5%	14905
	Night	19% 10% 29% 29% 12% 1	24313

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	16% 17% 7% 12% 5% 4 4 3 4 6% 21%	2711
	11th to 20th	Day	12% 20% 9% 17% 8% 4 4 3 5% 4 13%	2930
	21st to end	Day	23% 20% 7% 12% 6% 4 5% 3 4 3 13%	3133
February	1st to 10th	Day	15% 18% 5% 11% 7% 6% 5% 3 4 5% 19%	1710
	11th to 20th	Day	13% 15% 8% 15% 6% 5% 5% 3 4 5% 21%	1663
	21st to end	Day	18% 13% 5% 11% 7% 5% 5% 4 4 5% 23%	1527
March	1st to 10th	Day	20% 14% 4 9% 6% 4 4 2 4 5% 27%	3402
	11th to 20th	Day	11% 15% 5% 10% 6% 4 4 3 5% 8% 29%	3480
	21st to end	Day	18% 10% 3 9% 5% 5% 4 4 4 5% 32%	3815
April	1st to 10th	Day	16% 14% 4 8% 5% 4 4 3 6% 7% 29%	2190
	11th to 20th	Day	17% 10% 4 8% 6% 4 3 3 5% 7% 34%	2372
	21st to end	Day	20% 10% 3 7% 4 4 4 4 4 7% 32%	2470
May	1st to 10th	Day	19% 8% 2 8% 5% 5% 5% 4 6% 7% 31%	4108
	11th to 20th	Day	15% 10% 4 8% 5% 5% 4 4 7% 8% 31%	4171
	21st to end	Day	11% 5% 2 6% 4 4 4 4 5% 8% 46%	4837
June	1st to 10th	Day	13% 6% 3 7% 5% 4 5% 4 6% 8% 40%	2660
	11th to 20th	Day	11% 6% 3 7% 5% 5% 5% 4 8% 9% 38%	2660
	21st to end	Day	12% 6% 2 5% 4 4 5% 5% 7% 11% 39%	2841
July	1st to 10th	Day	9% 5% 2 6% 4 5% 5% 4 7% 10% 42%	4550
	11th to 20th	Day	11% 5% 2 5% 5% 4 5% 4 7% 10% 42%	4228
	21st to end	Day	7% 5% 2 7% 5% 5% 6% 5% 8% 10% 41%	4466
August	1st to 10th	Day	16% 6% 2 5% 4 4 5% 4 7% 9% 37%	4104
	11th to 20th	Day	11% 6% 3 6% 5% 5% 6% 5% 8% 10% 35%	4044
	21st to end	Day	9% 6% 3 7% 5% 4 5% 4 6% 9% 42%	4413
September	1st to 10th	Day	12% 6% 2 6% 5% 5% 5% 5% 6% 8% 40%	2278
	11th to 20th	Day	9% 5% 2 5% 4 5% 5% 3 6% 9% 47%	2090
	21st to end	Day	15% 7% 2 8% 4 6% 5% 4 7% 7% 36%	2090
October	1st to 10th	Day	16% 8% 3 7% 5% 5% 4 4 6% 6% 36%	1909
	11th to 20th	Day	18% 10% 3 8% 4 4 5% 4 5% 6% 32%	1900
	21st to end	Day	22% 10% 4 9% 5% 5% 5% 4 6% 7% 24%	2090
November	1st to 10th	Day	14% 8% 3 8% 6% 4 5% 4 6% 7% 36%	1766
	11th to 20th	Day	15% 12% 3 8% 5% 4 5% 4 6% 9% 29%	1600
	21st to end	Day	20% 15% 4 9% 5% 5% 5% 4 6% 6% 21%	1600
December	1st to 10th	Day	18% 17% 5% 10% 7% 5% 5% 4 6% 6% 15%	2600
	11th to 20th	Day	22% 18% 5% 9% 4 4 4 4 5% 5% 21%	2986
	21st to end	Day	27% 19% 5% 10% 5% 5% 4 3 5% 5% 12%	3960
January	1st to 10th	Night	16% 15% 5% 11% 6% 5% 5% 4 5% 5% 22%	4437
	11th to 20th	Night	15% 14% 6% 14% 7% 6% 5% 4 5% 5% 18%	4250
	21st to end	Night	24% 16% 8% 14% 6% 4 4 3 4 4 15%	4546
February	1st to 10th	Night	15% 16% 4 10% 7% 5% 5% 5% 5% 5% 23%	2470
	11th to 20th	Night	15% 12% 6% 9% 7% 5% 5% 4 6% 6% 25%	2403
	21st to end	Night	18% 12% 4 10% 7% 5% 5% 4 5% 7% 22%	1924
March	1st to 10th	Night	18% 9% 3 8% 6% 4 4 3 4 6% 34%	3438
	11th to 20th	Night	13% 10% 4 7% 4 4 4 3 6% 7% 38%	3479
	21st to end	Night	16% 10% 4 6% 4 4 4 3 4 5% 40%	3817
April	1st to 10th	Night	18% 10% 3 7% 4 5% 5% 4 5% 7% 32%	1988
	11th to 20th	Night	18% 8% 3 6% 4 4 5% 3 6% 5% 36%	1773
	21st to end	Night	14% 7% 3 8% 6% 5% 4 5% 6% 7% 35%	1710
May	1st to 10th	Night	19% 8% 3 6% 5% 3 4 3 5% 7% 38%	2833
	11th to 20th	Night	11% 8% 3 8% 6% 5% 6% 4 5% 8% 37%	2719
	21st to end	Night	10% 5% 2 6% 3 3 4 4 6% 8% 50%	2738
June	1st to 10th	Night	11% 6% 2 6% 5% 4 4 5% 6% 8% 42%	1520
	11th to 20th	Night	8% 5% 2 5% 5% 5% 5% 5% 8% 10% 42%	1515
	21st to end	Night	10% 6% 2 5% 4 4 4 4 7% 8% 45%	1330
July	1st to 10th	Night	7% 5% 2 5% 4 4 4 2 6% 9% 51%	2391
	11th to 20th	Night	9% 5% 2 5% 4 4 4 4 6% 9% 50%	2728
	21st to end	Night	6% 4 1 6% 4 5% 5% 5% 7% 8% 49%	3087
August	1st to 10th	Night	10% 5% 3 6% 5% 4 4 4 5% 8% 45%	2825
	11th to 20th	Night	11% 6% 2 6% 3 4 4 4 6% 8% 47%	2785
	21st to end	Night	7% 5% 2 6% 3 4 5% 4 6% 10% 48%	3210
September	1st to 10th	Night	12% 6% 3 7% 4 3 4 3 5% 6% 46%	1900
	11th to 20th	Night	9% 4 2 5% 4 3 3 3 5% 6% 55%	2089
	21st to end	Night	15% 7% 2 7% 5% 5% 4 4 6% 6% 40%	2090
October	1st to 10th	Night	14% 6% 2 7% 5% 3 4 3 5% 7% 44%	2270
	11th to 20th	Night	17% 9% 3 7% 5% 5% 3 3 4 6% 37%	2280
	21st to end	Night	20% 9% 3 7% 5% 4 4 4 5% 7% 32%	2508
November	1st to 10th	Night	15% 7% 2 6% 4 4 4 4 6% 7% 40%	2529
	11th to 20th	Night	16% 10% 3 8% 6% 6% 4 4 6% 7% 30%	2800
	21st to end	Night	20% 12% 4 8% 5% 4 4 4 5% 7% 25%	2800
December	1st to 10th	Night	14% 16% 5% 10% 6% 6% 6% 5% 7% 7% 19%	4580
	11th to 20th	Night	17% 19% 5% 10% 6% 4 4 3 4 5% 23%	5208
	21st to end	Night	25% 18% 5% 9% 5% 4 4 3 4 5% 18%	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	63% 8% 13% 9% 7%	2712
	11th to 20th	Day	71% 9% 11% 5% 3	2930
	21st to end	Day	74% 8% 9% 6% 3	3133
February	1st to 10th	Day	67% 6% 11% 11% 4 1	1710
	11th to 20th	Day	63% 7% 10% 15% 6%	1672
	21st to end	Day	62% 7% 12% 13% 6% 1	1527
March	1st to 10th	Day	58% 7% 11% 19% 4	3405
	11th to 20th	Day	51% 8% 17% 17% 6% 1	3480
	21st to end	Day	49% 8% 13% 19% 10% 1	3815
April	1st to 10th	Day	54% 7% 11% 16% 11% 1	2190
	11th to 20th	Day	49% 6% 12% 20% 12% 1	2372
	21st to end	Day	50% 8% 12% 17% 11% 2	2470
May	1st to 10th	Day	48% 8% 15% 17% 10% 2	4120
	11th to 20th	Day	46% 11% 17% 18% 7% 1	4175
	21st to end	Day	34% 9% 15% 20% 19% 4	4837
June	1st to 10th	Day	39% 8% 14% 24% 13% 2	2660
	11th to 20th	Day	39% 9% 15% 21% 14% 2	2660
	21st to end	Day	37% 8% 15% 24% 15%	2841
July	1st to 10th	Day	35% 7% 14% 26% 15% 3	4480
	11th to 20th	Day	35% 8% 16% 28% 13% 1	4155
	21st to end	Day	35% 9% 17% 20% 18% 1	4324
August	1st to 10th	Day	42% 8% 16% 21% 13% 1	4091
	11th to 20th	Day	40% 9% 17% 25% 8% 1	4083
	21st to end	Day	36% 7% 14% 30% 12% 1	4413
September	1st to 10th	Day	38% 9% 16% 24% 12% 1	2278
	11th to 20th	Day	32% 8% 16% 28% 15%	2090
	21st to end	Day	45% 7% 14% 22% 11% 1	2090
October	1st to 10th	Day	38% 6% 16% 22% 17% 1	3169
	11th to 20th	Day	38% 6% 15% 22% 18%	3140
	21st to end	Day	48% 6% 17% 23% 7%	3428
November	1st to 10th	Day	46% 7% 14% 23% 8% 2	1766
	11th to 20th	Day	50% 9% 16% 16% 9%	1600
	21st to end	Day	59% 9% 15% 13% 4	1600
December	1st to 10th	Day	67% 7% 15% 9% 2	2600
	11th to 20th	Day	63% 8% 13% 7% 8%	2986
	21st to end	Day	74% 6% 8% 7% 4	3960
January	1st to 10th	Night	59% 10% 14% 11% 5% 1	4437
	11th to 20th	Night	63% 11% 15% 7% 3	4250
	21st to end	Night	71% 8% 9% 8% 3 1	4546
February	1st to 10th	Night	61% 7% 12% 14% 5% 1	2470
	11th to 20th	Night	58% 7% 13% 16% 7%	2405
	21st to end	Night	58% 8% 12% 15% 7% 1	1924
March	1st to 10th	Night	50% 7% 15% 21% 6% 1	3448
	11th to 20th	Night	42% 8% 18% 19% 12% 1	3480
	21st to end	Night	43% 8% 11% 21% 16% 2	3817
April	1st to 10th	Night	51% 6% 12% 17% 12% 1	1988
	11th to 20th	Night	47% 6% 9% 20% 16% 2	1773
	21st to end	Night	43% 9% 11% 19% 14% 3	1710
May	1st to 10th	Night	44% 7% 12% 18% 14% 4	2840
	11th to 20th	Night	43% 10% 17% 21% 8% 2	2720
	21st to end	Night	30% 8% 14% 22% 23% 3	2739
June	1st to 10th	Night	37% 8% 12% 25% 16% 3	1520
	11th to 20th	Night	34% 8% 14% 24% 17% 2	1515
	21st to end	Night	34% 8% 14% 23% 19% 1	1330
July	1st to 10th	Night	31% 4 13% 26% 20% 5%	2351
	11th to 20th	Night	31% 6% 14% 31% 17% 1	2678
	21st to end	Night	30% 9% 16% 23% 19% 3	2988
August	1st to 10th	Night	36% 6% 15% 25% 17% 2	2814
	11th to 20th	Night	34% 8% 18% 29% 11% 1	2812
	21st to end	Night	30% 7% 14% 32% 16% 1	3210
September	1st to 10th	Night	37% 7% 12% 25% 16% 2	1900
	11th to 20th	Night	28% 6% 15% 31% 19% 1	2089
	21st to end	Night	44% 8% 11% 24% 13% 1	2090
October	1st to 10th	Night	31% 5% 10% 28% 24% 2	3790
	11th to 20th	Night	41% 5% 14% 24% 16%	3779
	21st to end	Night	39% 6% 15% 25% 14% 1	4120
November	1st to 10th	Night	41% 7% 14% 25% 13% 1	2529
	11th to 20th	Night	50% 8% 14% 18% 9% 1	2800
	21st to end	Night	56% 8% 16% 14% 4 1	2800
December	1st to 10th	Night	61% 8% 16% 11% 3	4580
	11th to 20th	Night	63% 6% 11% 11% 9% 1	5208
	21st to end	Night	67% 7% 11% 10% 5%	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	22% 22% 34% 14% 7% 2	237
	11th to 20th	Day	24% 20% 39% 13% 4 1	300
	21st to end	Day	24% 19% 35% 18% 3 1	300
February	1st to 10th	Day	25% 17% 41% 12% 4	270
	11th to 20th	Day	22% 22% 38% 16% 1	270
	21st to end	Day	25% 28% 34% 11% 2	225
March	1st to 10th	Day	23% 14% 35% 22% 6% 1	441
	11th to 20th	Day	22% 16% 37% 19% 5% 1	460
	21st to end	Day	28% 14% 29% 22% 6%	506
April	1st to 10th	Day	19% 18% 32% 22% 8% 1	460
	11th to 20th	Day	24% 15% 28% 19% 10% 4	452
	21st to end	Day	22% 13% 32% 22% 8% 2	460
May	1st to 10th	Day	23% 11% 28% 24% 10% 5%	463
	11th to 20th	Day	18% 9% 25% 26% 18% 4	487
	21st to end	Day	12% 9% 23% 31% 18% 7%	529
June	1st to 10th	Day	12% 8% 33% 31% 13% 3	490
	11th to 20th	Day	15% 8% 24% 32% 16% 5%	490
	21st to end	Day	13% 6% 31% 34% 13% 3	671
July	1st to 10th	Day	10% 3 22% 30% 26% 9%	556
	11th to 20th	Day	12% 6% 23% 29% 19% 11%	484
	21st to end	Day	8% 3 25% 34% 23% 7%	532
August	1st to 10th	Day	11% 3 21% 31% 21% 14%	486
	11th to 20th	Day	10% 6% 19% 29% 21% 15%	479
	21st to end	Day	10% 4 22% 29% 23% 11%	539
September	1st to 10th	Day	12% 6% 23% 27% 20% 12%	490
	11th to 20th	Day	8% 4 18% 27% 27% 17%	490
	21st to end	Day	17% 10% 24% 27% 15% 7%	490
October	1st to 10th	Day	17% 10% 26% 22% 18% 6%	490
	11th to 20th	Day	18% 17% 33% 22% 7% 3	490
	21st to end	Day	25% 15% 31% 21% 8%	539
November	1st to 10th	Day	17% 24% 30% 19% 8% 2	309
	11th to 20th	Day	23% 20% 31% 19% 5% 3	200
	21st to end	Day	31% 14% 35% 18% 4	200
December	1st to 10th	Day	27% 24% 28% 15% 6% 1	200
	11th to 20th	Day	27% 25% 32% 14% 3	200
	21st to end	Day	29% 18% 34% 15% 4	220
January	1st to 10th	Night	22% 19% 35% 19% 5% 1	800
	11th to 20th	Night	26% 20% 31% 20% 3	800
	21st to end	Night	20% 14% 36% 24% 5%	841
February	1st to 10th	Night	24% 15% 36% 22% 2	760
	11th to 20th	Night	22% 15% 35% 24% 4	743
	21st to end	Night	23% 15% 36% 22% 3	628
March	1st to 10th	Night	17% 13% 36% 28% 6%	760
	11th to 20th	Night	20% 12% 37% 24% 7%	760
	21st to end	Night	22% 10% 32% 27% 9%	836
April	1st to 10th	Night	22% 13% 31% 29% 4	760
	11th to 20th	Night	22% 12% 32% 25% 8% 1	649
	21st to end	Night	18% 7% 34% 32% 9%	570
May	1st to 10th	Night	19% 7% 28% 31% 15% 1	570
	11th to 20th	Night	15% 5% 26% 39% 14% 1	507
	21st to end	Night	13% 4 26% 36% 20% 1	411
June	1st to 10th	Night	14% 4 29% 39% 14% 1	380
	11th to 20th	Night	11% 3 29% 42% 16%	380
	21st to end	Night	12% 5% 25% 43% 14% 1	380
July	1st to 10th	Night	6% 3 21% 45% 22% 3	370
	11th to 20th	Night	9% 4 20% 40% 24% 4	483
	21st to end	Night	8% 2 18% 47% 22% 3	624
August	1st to 10th	Night	8% 2 16% 43% 29% 3	567
	11th to 20th	Night	10% 2 17% 34% 33% 3	564
	21st to end	Night	9% 3 21% 38% 26% 3	674
September	1st to 10th	Night	14% 5% 19% 34% 24% 5%	760
	11th to 20th	Night	11% 4 15% 35% 30% 5%	760
	21st to end	Night	17% 7% 21% 31% 20% 5%	760
October	1st to 10th	Night	17% 8% 24% 29% 19% 3	760
	11th to 20th	Night	20% 13% 29% 27% 10% 2	760
	21st to end	Night	25% 11% 32% 26% 6%	836
November	1st to 10th	Night	19% 11% 31% 27% 10% 1	780
	11th to 20th	Night	22% 17% 33% 20% 7% 2	800
	21st to end	Night	26% 14% 33% 20% 7%	800
December	1st to 10th	Night	28% 17% 33% 17% 5% 1	800
	11th to 20th	Night	23% 18% 37% 18% 3	800
	21st to end	Night	30% 13% 32% 23% 3	880

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